TY  - JOUR
AU  - Milenković, Mila
AU  - Ciasca, Gabriele
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera
AU  - Verbić, Tatjana
AU  - Todorović Marković, Biljana
AU  - Jovanović, Svetlana
PY  - 2024
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/7093
AB  - The widespread abuse of traditional antibiotics has led to a global rise in antibiotic-resistant bacteria, which give in return unprecedented health risks. Therefore, there is a large and urgent need for the development of new, smart antibacterial agents able to efficiently kill or inhibit bacterial growth. In this study, we investigated the antibacterial activity of S, N-doped Graphene Quantum Dots (GQDs) as a light-triggered antibacterial agent. Gamma irradiation was employed as a tool to achieve one-step modification of GQDs in the presence of L-cysteine amino acid as a source of heteroatoms. X-ray Photoelectron Spectroscopy (XPS), nuclear magnetic 
resonance (NMR), and zeta potential measurements provided the necessary data to clarify the structure of modified dots and verify the introduction of both S- and N-atoms in GQDs structure, but also severe changes in the aromatic, sp2 domains. Namely, γ-irradiation caused a bonding of S atoms in 1.14 at.% mainly as thiol groups, and N in 1.81 at.% as amino groups, but sp2 contribution in GQD structure was lowered from 63.00 to 4.86 at.%, as measured in dots irradiated at a dose of 200 kGy. Fluorescence quenching measurements showed that L-cysteine-modified dots are able to bind to human serum albumin. The antibacterial activity of GQDs 
combined with 1 and 6 h of blue light (470 nm) irradiation was tested against 8 bacterial strains. GQD-cys-25 sample provided the best results, with minimum inhibitory concentration (MIC) as low as 125 μg/mL against S. aureus, E. faecalis, and E. coli after only 1 h of blue light exposure.
PB  - Elsevier
T2  - Journal of Photochemistry and Photobiology, B: Biology
T1  - Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects
VL  - 250
SP  - 112818
DO  - 10.1016/j.jphotobiol.2023.112818
ER  - 

@article{
author = "Milenković, Mila and Ciasca, Gabriele and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera and Verbić, Tatjana and Todorović Marković, Biljana and Jovanović, Svetlana",
year = "2024",
abstract = "The widespread abuse of traditional antibiotics has led to a global rise in antibiotic-resistant bacteria, which give in return unprecedented health risks. Therefore, there is a large and urgent need for the development of new, smart antibacterial agents able to efficiently kill or inhibit bacterial growth. In this study, we investigated the antibacterial activity of S, N-doped Graphene Quantum Dots (GQDs) as a light-triggered antibacterial agent. Gamma irradiation was employed as a tool to achieve one-step modification of GQDs in the presence of L-cysteine amino acid as a source of heteroatoms. X-ray Photoelectron Spectroscopy (XPS), nuclear magnetic 
resonance (NMR), and zeta potential measurements provided the necessary data to clarify the structure of modified dots and verify the introduction of both S- and N-atoms in GQDs structure, but also severe changes in the aromatic, sp2 domains. Namely, γ-irradiation caused a bonding of S atoms in 1.14 at.% mainly as thiol groups, and N in 1.81 at.% as amino groups, but sp2 contribution in GQD structure was lowered from 63.00 to 4.86 at.%, as measured in dots irradiated at a dose of 200 kGy. Fluorescence quenching measurements showed that L-cysteine-modified dots are able to bind to human serum albumin. The antibacterial activity of GQDs 
combined with 1 and 6 h of blue light (470 nm) irradiation was tested against 8 bacterial strains. GQD-cys-25 sample provided the best results, with minimum inhibitory concentration (MIC) as low as 125 μg/mL against S. aureus, E. faecalis, and E. coli after only 1 h of blue light exposure.",
publisher = "Elsevier",
journal = "Journal of Photochemistry and Photobiology, B: Biology",
title = "Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects",
volume = "250",
pages = "112818",
doi = "10.1016/j.jphotobiol.2023.112818"
}

Milenković, M., Ciasca, G., Bonasera, A., Scopelliti, M., Marković, O., Verbić, T., Todorović Marković, B.,& Jovanović, S.. (2024). Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects. in Journal of Photochemistry and Photobiology, B: Biology
Elsevier., 250, 112818.
https://doi.org/10.1016/j.jphotobiol.2023.112818

Milenković M, Ciasca G, Bonasera A, Scopelliti M, Marković O, Verbić T, Todorović Marković B, Jovanović S. Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects. in Journal of Photochemistry and Photobiology, B: Biology. 2024;250:112818.
doi:10.1016/j.jphotobiol.2023.112818 .

Milenković, Mila, Ciasca, Gabriele, Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera, Verbić, Tatjana, Todorović Marković, Biljana, Jovanović, Svetlana, "Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects" in Journal of Photochemistry and Photobiology, B: Biology, 250 (2024):112818,
https://doi.org/10.1016/j.jphotobiol.2023.112818 . .

TY  - CONF
AU  - Verbić, Tatjana Ž.
AU  - Avdeef, Alex
AU  - Tam, Kin Y.
AU  - Marković, Olivera S.
AU  - Pešić, Miloš P.
AU  - Topalović, Igor A.
AU  - Veljković, Dušan Ž.
AU  - Kathawala, Mufaddal
AU  - Serajuddin, Abu T. M.
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6567
AB  - Since the introduction of combinatorial chemistry and high-throughput screening in drug 
discovery in the early 1990s, the solubility of new chemical entities (NCE) decreased drastically 
while their lipophilicities increased greatly. Characterizing physicochemical properties of low soluble molecules can be especially challenging, since such molecules can undergo 
complicated reactions in aqueous solution, such as forming precipitates or complexes with 
buffer species or undergoing self-aggregation (dimer, trimer, etc.) or micelle formations. 
Most drugs are ionizable. Foremost to the rational interpretation of solution behavior of 
ionizable drugs in a physiologically-relevant pH domain requires an accurate aqueous pKa, 
determined by a suitable method. In a pH-dependent measurement of a property (e.g. 
solubility-, lipophilicity-, permeability-pH), when the apparent pKa value is different from the 
true aqueous pKa value, it may be an early clue that nonideal solution behavior may be taking 
place. In pharmaceutical research, it may seem cost-effective to use calculated pKa instead of 
measured values, but paradoxically, such preference can lead to inaccurate rationalization of 
the pH-dependent behavior of the drug molecule. For simple molecules, calculated values can 
be useful, but for today’s new drugs or for molecules prone to complicated solution behavior, 
the use of calculated pKas can substantially wrench the interpretation of solution properties. 
Clofazimine (CFZ), although discovered about 66 years ago, and used therapeutically for nearly 
40 years, exhibits some of the properties of relatively recent drug molecules by being 
extremely water insoluble and having variable pKa values reported. We have recently 
combined potentiometric titrations and UV/Vis spectrophotometry in methanol-water 
cosolvent media, accompanied by DFT calculations, to assess the hypothesis of CFZ free base 
dimerization. We reasoned that a soluble dimer might form from drug-drug adhesion along 
the hydrophobic molecular surface. With lessened exposure of the hydrophobic surface to 
water, the dimer would be more water soluble than the monomeric free base. In saturated 
solutions, the apparent solubility in alkaline pH would be elevated due to the presence of the 
dimer. The effect of that would be a lower pKa and reverse pKa cosolvent dependence – the 
behaviour we have noticed in CFZ aqueous solutions. These findings are of paramount 
importance for understanding of CFZ speciation and the future progress in developing its 
improved formulations which is the subject of our ongoing studies.
PB  - International Association of Physical Chemists
C3  - Book of Abstracts - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK, September 4-6, 2023, Belgrade, Serbia
T1  - Revealing the story of an orphan drug: clofazimine speciation  and solubilization as a function of pH
SP  - 15
EP  - 15
UR  - https://hdl.handle.net/21.15107/rcub_cer_6567
ER  - 

@conference{
author = "Verbić, Tatjana Ž. and Avdeef, Alex and Tam, Kin Y. and Marković, Olivera S. and Pešić, Miloš P. and Topalović, Igor A. and Veljković, Dušan Ž. and Kathawala, Mufaddal and Serajuddin, Abu T. M.",
year = "2023",
abstract = "Since the introduction of combinatorial chemistry and high-throughput screening in drug 
discovery in the early 1990s, the solubility of new chemical entities (NCE) decreased drastically 
while their lipophilicities increased greatly. Characterizing physicochemical properties of low soluble molecules can be especially challenging, since such molecules can undergo 
complicated reactions in aqueous solution, such as forming precipitates or complexes with 
buffer species or undergoing self-aggregation (dimer, trimer, etc.) or micelle formations. 
Most drugs are ionizable. Foremost to the rational interpretation of solution behavior of 
ionizable drugs in a physiologically-relevant pH domain requires an accurate aqueous pKa, 
determined by a suitable method. In a pH-dependent measurement of a property (e.g. 
solubility-, lipophilicity-, permeability-pH), when the apparent pKa value is different from the 
true aqueous pKa value, it may be an early clue that nonideal solution behavior may be taking 
place. In pharmaceutical research, it may seem cost-effective to use calculated pKa instead of 
measured values, but paradoxically, such preference can lead to inaccurate rationalization of 
the pH-dependent behavior of the drug molecule. For simple molecules, calculated values can 
be useful, but for today’s new drugs or for molecules prone to complicated solution behavior, 
the use of calculated pKas can substantially wrench the interpretation of solution properties. 
Clofazimine (CFZ), although discovered about 66 years ago, and used therapeutically for nearly 
40 years, exhibits some of the properties of relatively recent drug molecules by being 
extremely water insoluble and having variable pKa values reported. We have recently 
combined potentiometric titrations and UV/Vis spectrophotometry in methanol-water 
cosolvent media, accompanied by DFT calculations, to assess the hypothesis of CFZ free base 
dimerization. We reasoned that a soluble dimer might form from drug-drug adhesion along 
the hydrophobic molecular surface. With lessened exposure of the hydrophobic surface to 
water, the dimer would be more water soluble than the monomeric free base. In saturated 
solutions, the apparent solubility in alkaline pH would be elevated due to the presence of the 
dimer. The effect of that would be a lower pKa and reverse pKa cosolvent dependence – the 
behaviour we have noticed in CFZ aqueous solutions. These findings are of paramount 
importance for understanding of CFZ speciation and the future progress in developing its 
improved formulations which is the subject of our ongoing studies.",
publisher = "International Association of Physical Chemists",
journal = "Book of Abstracts - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK, September 4-6, 2023, Belgrade, Serbia",
title = "Revealing the story of an orphan drug: clofazimine speciation  and solubilization as a function of pH",
pages = "15-15",
url = "https://hdl.handle.net/21.15107/rcub_cer_6567"
}

Verbić, T. Ž., Avdeef, A., Tam, K. Y., Marković, O. S., Pešić, M. P., Topalović, I. A., Veljković, D. Ž., Kathawala, M.,& Serajuddin, A. T. M.. (2023). Revealing the story of an orphan drug: clofazimine speciation  and solubilization as a function of pH. in Book of Abstracts - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK, September 4-6, 2023, Belgrade, Serbia
International Association of Physical Chemists., 15-15.
https://hdl.handle.net/21.15107/rcub_cer_6567

Verbić TŽ, Avdeef A, Tam KY, Marković OS, Pešić MP, Topalović IA, Veljković DŽ, Kathawala M, Serajuddin ATM. Revealing the story of an orphan drug: clofazimine speciation  and solubilization as a function of pH. in Book of Abstracts - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK, September 4-6, 2023, Belgrade, Serbia. 2023;:15-15.
https://hdl.handle.net/21.15107/rcub_cer_6567 .

Verbić, Tatjana Ž., Avdeef, Alex, Tam, Kin Y., Marković, Olivera S., Pešić, Miloš P., Topalović, Igor A., Veljković, Dušan Ž., Kathawala, Mufaddal, Serajuddin, Abu T. M., "Revealing the story of an orphan drug: clofazimine speciation  and solubilization as a function of pH" in Book of Abstracts - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK, September 4-6, 2023, Belgrade, Serbia (2023):15-15,
https://hdl.handle.net/21.15107/rcub_cer_6567 .

TY  - CONF
AU  - Topalović, Igor A.
AU  - Marković, Olivera S.
AU  - Pešić, Miloš P.
AU  - Kathawala, Mufaddal
AU  - Serajuddin, Abu T. M.
AU  - Avdeef, Alex
AU  - Verbić, Tatjana Ž.
PY  - 2023
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6566
AB  - Methods for drug solubilization have become important part of modern drug discovery and 
development due to increasing number of extremely insoluble drugs and drug candidates. 
One of such methods is acid-base supersolubilization (ABS) [1]. Clofazimine (CFZ) is weakly 
basic antibiotic and anti-inflammatory drug, most notably used in the treatment of leprosy
and tuberculosis, with recently proven inhibitory activity against several coronaviruses [2].
We have recently unraveled its aqueous pKa value and its unique cosolvent dependence [3]. 
The aim of the present study was to investigate CFZ solubilization using the ABS approach. 
Eight small organic acids were tested for the ABS effect (glutaric, malic, tartaric, citric, 
malonic, maleic, succinic, adipic) but only glutaric (GA), malic (MA), and tartaric (TA) acids 
showed some solubilization effect. The effect of their concentration (and the solution pH 
value) was further tested. The solubility of CFZ was determined in GA, MA, and TA solutions 
in wide concentration (1.0×10-2 – 5.0 M) and pH range (~0.2 – 4.8). Equilibration time was 
24 hours (6 h of stirring + 18 h of sedimentation). Phases were separated by filtration. The 
CFZ concentration in supernatant was determined by HPLC-UV/VIS. Results show that CFZ 
solubility increases as acid concentration increases: from 3.04×10-3 to 10.68 mg/mL (in GA), 
from 9.06×10-3 to 1.23 mg/mL (in MA) and from 4.76×10-3 to 0.32 mg/mL (in TA). The effect 
of CFZ solubilization is much more pronounced when the acid concentration is raised above 
2 M. These results can be used as the basis for further CFZ formulation optimization.
Furthermore, our ongoing research is focused on the type of interactions and other possible 
factors that can influence CFZ and other prectically insoluble drugs, embracing (super)solubilization as a general methodology in drug design and development.
PB  - International Association of Physical Chemists
C3  - Book of Abstracts - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK, September 4-6, 2023, Belgrade, Serbia
T1  - Clofazimine acid-base solubilization: influence  of small organic acids’ concentration
SP  - 66
EP  - 66
UR  - https://hdl.handle.net/21.15107/rcub_cer_6566
ER  - 

@conference{
author = "Topalović, Igor A. and Marković, Olivera S. and Pešić, Miloš P. and Kathawala, Mufaddal and Serajuddin, Abu T. M. and Avdeef, Alex and Verbić, Tatjana Ž.",
year = "2023",
abstract = "Methods for drug solubilization have become important part of modern drug discovery and 
development due to increasing number of extremely insoluble drugs and drug candidates. 
One of such methods is acid-base supersolubilization (ABS) [1]. Clofazimine (CFZ) is weakly 
basic antibiotic and anti-inflammatory drug, most notably used in the treatment of leprosy
and tuberculosis, with recently proven inhibitory activity against several coronaviruses [2].
We have recently unraveled its aqueous pKa value and its unique cosolvent dependence [3]. 
The aim of the present study was to investigate CFZ solubilization using the ABS approach. 
Eight small organic acids were tested for the ABS effect (glutaric, malic, tartaric, citric, 
malonic, maleic, succinic, adipic) but only glutaric (GA), malic (MA), and tartaric (TA) acids 
showed some solubilization effect. The effect of their concentration (and the solution pH 
value) was further tested. The solubility of CFZ was determined in GA, MA, and TA solutions 
in wide concentration (1.0×10-2 – 5.0 M) and pH range (~0.2 – 4.8). Equilibration time was 
24 hours (6 h of stirring + 18 h of sedimentation). Phases were separated by filtration. The 
CFZ concentration in supernatant was determined by HPLC-UV/VIS. Results show that CFZ 
solubility increases as acid concentration increases: from 3.04×10-3 to 10.68 mg/mL (in GA), 
from 9.06×10-3 to 1.23 mg/mL (in MA) and from 4.76×10-3 to 0.32 mg/mL (in TA). The effect 
of CFZ solubilization is much more pronounced when the acid concentration is raised above 
2 M. These results can be used as the basis for further CFZ formulation optimization.
Furthermore, our ongoing research is focused on the type of interactions and other possible 
factors that can influence CFZ and other prectically insoluble drugs, embracing (super)solubilization as a general methodology in drug design and development.",
publisher = "International Association of Physical Chemists",
journal = "Book of Abstracts - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK, September 4-6, 2023, Belgrade, Serbia",
title = "Clofazimine acid-base solubilization: influence  of small organic acids’ concentration",
pages = "66-66",
url = "https://hdl.handle.net/21.15107/rcub_cer_6566"
}

Topalović, I. A., Marković, O. S., Pešić, M. P., Kathawala, M., Serajuddin, A. T. M., Avdeef, A.,& Verbić, T. Ž.. (2023). Clofazimine acid-base solubilization: influence  of small organic acids’ concentration. in Book of Abstracts - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK, September 4-6, 2023, Belgrade, Serbia
International Association of Physical Chemists., 66-66.
https://hdl.handle.net/21.15107/rcub_cer_6566

Topalović IA, Marković OS, Pešić MP, Kathawala M, Serajuddin ATM, Avdeef A, Verbić TŽ. Clofazimine acid-base solubilization: influence  of small organic acids’ concentration. in Book of Abstracts - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK, September 4-6, 2023, Belgrade, Serbia. 2023;:66-66.
https://hdl.handle.net/21.15107/rcub_cer_6566 .

Topalović, Igor A., Marković, Olivera S., Pešić, Miloš P., Kathawala, Mufaddal, Serajuddin, Abu T. M., Avdeef, Alex, Verbić, Tatjana Ž., "Clofazimine acid-base solubilization: influence  of small organic acids’ concentration" in Book of Abstracts - 10th IAPC Meeting: Tenth World Conference on Physico-Chemical Methods in Drug Discovery & Sixth World Conference on ADMET and DMPK, September 4-6, 2023, Belgrade, Serbia (2023):66-66,
https://hdl.handle.net/21.15107/rcub_cer_6566 .

TY  - CONF
AU  - Mrđan, Gorana
AU  - Vaštag, Đenđi
AU  - Apostolov, Suzana
AU  - Rašeta, Milena
AU  - Verbić, Tatjana
AU  - Marković, Olivera
AU  - Matijević, Borko
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5151
AB  - Карбохидразони и њихови тио-аналози представљају
једињења добијена кондензацијом карбохидразида, односно тиокарбохи-
дразида са карбонилним једињењима. Захваљујући њиховој структури,
релативно једноставној синтези и великој реактивности, поменути дери-
вати имају широк спектар примене у свим сферама. У оквиру овог рада,
за четири новосинтетисана моно(тио)карбохидразона, одређене су кисе-
линске константе применом потенциметријске методе. Такође, методом
линеарне корелације енергија солватације и применом Catalan-овог моде-
ла испитан је утицај специфичних и неспецифичних међумолекулских
интеракција на померања у UV-Vis апсорпционим спектрима. У циљу
испитивавања потенцијалне биолошке активности 2 - пиридин-(тио) кар-
бохидразона, применом DPPH теста, одређен је њихов антиоксидативни
потенцијал и закључено је да су деривати тиокарбохидразона значајно
активнији у односу на карбохидразоне.
AB  - Carbohydrazones and their thio analogs represent compounds
obtained by condensation of carbohydrazide and thiocarbohydrazide with carbonyl
compounds. Due to their structure, relatively simple synthesis, and high
reactivity, mentioned derivatives have a wide range of applications in all fields.
In this study, ionization constants of four newly synthesized mono(thio)carbohydrazones were determined by applying the potentiometric method.
Also, the influence of specific and nonspecific intermolecular interactions
on maxima shifting in UV-Vis absorption spectra was investigated and quantified
using the linear solvation energy relationships method and Catalan’s model.
Finally, by applying the DPPH assay, the antioxidant potential of the newly
synthesized compounds was determined, and thiocarbohydrazone derivatives
proved to be significantly more active when compared to carbo-hydrazones.
PB  - Banja Luka : Akademija nauka i unjetnosti Republike Srpske
C3  - Савремени материјали -  зборник радова / Contemporary Materials - proceedings
T1  - Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives
T1  - Испитивање физичко-хемијских својстава и потенцијалне биолошке активности деривата 2-пиридин-(тио) карбохидразона
UR  - https://hdl.handle.net/21.15107/rcub_cer_5151
ER  - 

@conference{
author = "Mrđan, Gorana and Vaštag, Đenđi and Apostolov, Suzana and Rašeta, Milena and Verbić, Tatjana and Marković, Olivera and Matijević, Borko",
year = "2022",
abstract = "Карбохидразони и њихови тио-аналози представљају
једињења добијена кондензацијом карбохидразида, односно тиокарбохи-
дразида са карбонилним једињењима. Захваљујући њиховој структури,
релативно једноставној синтези и великој реактивности, поменути дери-
вати имају широк спектар примене у свим сферама. У оквиру овог рада,
за четири новосинтетисана моно(тио)карбохидразона, одређене су кисе-
линске константе применом потенциметријске методе. Такође, методом
линеарне корелације енергија солватације и применом Catalan-овог моде-
ла испитан је утицај специфичних и неспецифичних међумолекулских
интеракција на померања у UV-Vis апсорпционим спектрима. У циљу
испитивавања потенцијалне биолошке активности 2 - пиридин-(тио) кар-
бохидразона, применом DPPH теста, одређен је њихов антиоксидативни
потенцијал и закључено је да су деривати тиокарбохидразона значајно
активнији у односу на карбохидразоне., Carbohydrazones and their thio analogs represent compounds
obtained by condensation of carbohydrazide and thiocarbohydrazide with carbonyl
compounds. Due to their structure, relatively simple synthesis, and high
reactivity, mentioned derivatives have a wide range of applications in all fields.
In this study, ionization constants of four newly synthesized mono(thio)carbohydrazones were determined by applying the potentiometric method.
Also, the influence of specific and nonspecific intermolecular interactions
on maxima shifting in UV-Vis absorption spectra was investigated and quantified
using the linear solvation energy relationships method and Catalan’s model.
Finally, by applying the DPPH assay, the antioxidant potential of the newly
synthesized compounds was determined, and thiocarbohydrazone derivatives
proved to be significantly more active when compared to carbo-hydrazones.",
publisher = "Banja Luka : Akademija nauka i unjetnosti Republike Srpske",
journal = "Савремени материјали -  зборник радова / Contemporary Materials - proceedings",
title = "Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives, Испитивање физичко-хемијских својстава и потенцијалне биолошке активности деривата 2-пиридин-(тио) карбохидразона",
url = "https://hdl.handle.net/21.15107/rcub_cer_5151"
}

Mrđan, G., Vaštag, Đ., Apostolov, S., Rašeta, M., Verbić, T., Marković, O.,& Matijević, B.. (2022). Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives. in Савремени материјали -  зборник радова / Contemporary Materials - proceedings
Banja Luka : Akademija nauka i unjetnosti Republike Srpske..
https://hdl.handle.net/21.15107/rcub_cer_5151

Mrđan G, Vaštag Đ, Apostolov S, Rašeta M, Verbić T, Marković O, Matijević B. Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives. in Савремени материјали -  зборник радова / Contemporary Materials - proceedings. 2022;.
https://hdl.handle.net/21.15107/rcub_cer_5151 .

Mrđan, Gorana, Vaštag, Đenđi, Apostolov, Suzana, Rašeta, Milena, Verbić, Tatjana, Marković, Olivera, Matijević, Borko, "Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives" in Савремени материјали -  зборник радова / Contemporary Materials - proceedings (2022),
https://hdl.handle.net/21.15107/rcub_cer_5151 .

TY  - JOUR
AU  - Dorontić, Slađana
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera
AU  - Bajuk-Bogdanović, Danica
AU  - Ciasca, Gabriele
AU  - Romanò, Sabrina
AU  - Dimkić, Ivica
AU  - Budimir, Milica
AU  - Marinković, Dragana
AU  - Jovanović, Svetlana
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5222
AB  - Structural modification of different carbon-based nanomaterials is often necessary to improve their morphology and optical properties, particularly the incorporation of N-atoms in graphene quantum dots (GQDs). Here, a clean, simple, one-step, and eco-friendly method for N-doping of GQDs using gamma irradiation is reported. GQDs were irradiated in the presence of the different ethylenediamine (EDA) amounts (1 g, 5 g, and 10 g) and the highest % of N was detected in the presence of 10 g. N-doped GQDs emitted strong, blue photoluminescence (PL). Photoluminescence quantum yield was increased from 1.45, as obtained for non-irradiated dots, to 7.24% for those irradiated in the presence of 1 g of EDA. Modified GQDs were investigated as a PL probe for the detection of insecticide Carbofuran (2,2-Dimethyl-2,3-dihydro-1-benzofuran-7-yl methylcarbamate) and herbicide Amitrole (3-amino-1,2,4-triazole). The limit of detection was 5.4 μmol L−1 for Carbofuran. For the first time, Amitrole was detected by GQDs in a turn-off/turn-on mechanism using Pd(II) ions as a quenching agent. First, Pd(II) ions were quenched (turn-off) PL of GQDs, while after Amitrole addition, PL was recovered linearly with Amitrole concentration (turn-on). LOD was 2.03 μmol L−1. These results suggest that modified GQDs can be used as an efficient new material for Carbofuran and Amitrole detection. Furthermore, the phototoxicity of dots was investigated on both Gram-positive and Gram-negative bacterial strains. When bacterial cells were exposed to different GQD concentrations and illuminated with light of 470 nm wavelength, the toxic effects were not observed.
PB  - MDPI
T2  - Nanomaterials
T1  - Gamma-Ray-Induced Structural Transformation of GQDs towards the Improvement of Their Optical Properties, Monitoring of Selected Toxic Compounds, and Photo-Induced Effects on Bacterial Strains
VL  - 12
IS  - 15
SP  - 2714
DO  - 10.3390/nano12152714
ER  - 

@article{
author = "Dorontić, Slađana and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera and Bajuk-Bogdanović, Danica and Ciasca, Gabriele and Romanò, Sabrina and Dimkić, Ivica and Budimir, Milica and Marinković, Dragana and Jovanović, Svetlana",
year = "2022",
abstract = "Structural modification of different carbon-based nanomaterials is often necessary to improve their morphology and optical properties, particularly the incorporation of N-atoms in graphene quantum dots (GQDs). Here, a clean, simple, one-step, and eco-friendly method for N-doping of GQDs using gamma irradiation is reported. GQDs were irradiated in the presence of the different ethylenediamine (EDA) amounts (1 g, 5 g, and 10 g) and the highest % of N was detected in the presence of 10 g. N-doped GQDs emitted strong, blue photoluminescence (PL). Photoluminescence quantum yield was increased from 1.45, as obtained for non-irradiated dots, to 7.24% for those irradiated in the presence of 1 g of EDA. Modified GQDs were investigated as a PL probe for the detection of insecticide Carbofuran (2,2-Dimethyl-2,3-dihydro-1-benzofuran-7-yl methylcarbamate) and herbicide Amitrole (3-amino-1,2,4-triazole). The limit of detection was 5.4 μmol L−1 for Carbofuran. For the first time, Amitrole was detected by GQDs in a turn-off/turn-on mechanism using Pd(II) ions as a quenching agent. First, Pd(II) ions were quenched (turn-off) PL of GQDs, while after Amitrole addition, PL was recovered linearly with Amitrole concentration (turn-on). LOD was 2.03 μmol L−1. These results suggest that modified GQDs can be used as an efficient new material for Carbofuran and Amitrole detection. Furthermore, the phototoxicity of dots was investigated on both Gram-positive and Gram-negative bacterial strains. When bacterial cells were exposed to different GQD concentrations and illuminated with light of 470 nm wavelength, the toxic effects were not observed.",
publisher = "MDPI",
journal = "Nanomaterials",
title = "Gamma-Ray-Induced Structural Transformation of GQDs towards the Improvement of Their Optical Properties, Monitoring of Selected Toxic Compounds, and Photo-Induced Effects on Bacterial Strains",
volume = "12",
number = "15",
pages = "2714",
doi = "10.3390/nano12152714"
}

Dorontić, S., Bonasera, A., Scopelliti, M., Marković, O., Bajuk-Bogdanović, D., Ciasca, G., Romanò, S., Dimkić, I., Budimir, M., Marinković, D.,& Jovanović, S.. (2022). Gamma-Ray-Induced Structural Transformation of GQDs towards the Improvement of Their Optical Properties, Monitoring of Selected Toxic Compounds, and Photo-Induced Effects on Bacterial Strains. in Nanomaterials
MDPI., 12(15), 2714.
https://doi.org/10.3390/nano12152714

Dorontić S, Bonasera A, Scopelliti M, Marković O, Bajuk-Bogdanović D, Ciasca G, Romanò S, Dimkić I, Budimir M, Marinković D, Jovanović S. Gamma-Ray-Induced Structural Transformation of GQDs towards the Improvement of Their Optical Properties, Monitoring of Selected Toxic Compounds, and Photo-Induced Effects on Bacterial Strains. in Nanomaterials. 2022;12(15):2714.
doi:10.3390/nano12152714 .

Dorontić, Slađana, Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera, Bajuk-Bogdanović, Danica, Ciasca, Gabriele, Romanò, Sabrina, Dimkić, Ivica, Budimir, Milica, Marinković, Dragana, Jovanović, Svetlana, "Gamma-Ray-Induced Structural Transformation of GQDs towards the Improvement of Their Optical Properties, Monitoring of Selected Toxic Compounds, and Photo-Induced Effects on Bacterial Strains" in Nanomaterials, 12, no. 15 (2022):2714,
https://doi.org/10.3390/nano12152714 . .

TY  - JOUR
AU  - Marković, Olivera
AU  - Patel, Nirali G.
AU  - Serajuddin, Abu T. M.
AU  - Avdeef, Alex
AU  - Verbić, Tatjana
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4936
AB  - The solubility of a model basic drug, nortriptyline (Nor), was investigated as a function of pH in phosphate and/or a chloride-containing aqueous suspension using experimental practices recommended in the previously published “white paper” (Avdeef et al., 2016). The pH-Ramp Shake-Flask (pHRSF) method, introduced in our earlier work (Marković et al.,2019), was applied. An improved and more detailed experimentaldesign of the Nor solubility measurement allowed us to exploit thefull capacity of the pH-RSF method. Complex equilibria in theaqueous phase (cationic and anionic complex formation betweenNor and the phosphate) and solid-phase transformations (Nor freebase, 1:1 Nor hydrochloride salt, 1:1 and 1:2 Nor phosphate salts)were characterized by a detailed analysis of the solubilitymeasurements using the computer program pDISOL-X. The solid phases were characterized by thermogravimetric analysis,differential scanning calorimetry, powder X-ray diffraction, and elemental analyses. The results of the present investigation illustratethe influence of competing counterions, such as buffering agents, complexing agents, salt coformers, tonicity adjusters, and so forth,on the aqueous solubility of drugs and interconversion of salts. Careful attention given to these factors can be helpful in theformulation of drug products.
PB  - American Chemical Society (ACS)
T2  - Molecular Pharmaceutics
T1  - Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints
VL  - 19
IS  - 2
SP  - 710
EP  - 719
DO  - 10.1021/acs.molpharmaceut.1c00919
ER  - 

@article{
author = "Marković, Olivera and Patel, Nirali G. and Serajuddin, Abu T. M. and Avdeef, Alex and Verbić, Tatjana",
year = "2022",
abstract = "The solubility of a model basic drug, nortriptyline (Nor), was investigated as a function of pH in phosphate and/or a chloride-containing aqueous suspension using experimental practices recommended in the previously published “white paper” (Avdeef et al., 2016). The pH-Ramp Shake-Flask (pHRSF) method, introduced in our earlier work (Marković et al.,2019), was applied. An improved and more detailed experimentaldesign of the Nor solubility measurement allowed us to exploit thefull capacity of the pH-RSF method. Complex equilibria in theaqueous phase (cationic and anionic complex formation betweenNor and the phosphate) and solid-phase transformations (Nor freebase, 1:1 Nor hydrochloride salt, 1:1 and 1:2 Nor phosphate salts)were characterized by a detailed analysis of the solubilitymeasurements using the computer program pDISOL-X. The solid phases were characterized by thermogravimetric analysis,differential scanning calorimetry, powder X-ray diffraction, and elemental analyses. The results of the present investigation illustratethe influence of competing counterions, such as buffering agents, complexing agents, salt coformers, tonicity adjusters, and so forth,on the aqueous solubility of drugs and interconversion of salts. Careful attention given to these factors can be helpful in theformulation of drug products.",
publisher = "American Chemical Society (ACS)",
journal = "Molecular Pharmaceutics",
title = "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints",
volume = "19",
number = "2",
pages = "710-719",
doi = "10.1021/acs.molpharmaceut.1c00919"
}

Marković, O., Patel, N. G., Serajuddin, A. T. M., Avdeef, A.,& Verbić, T.. (2022). Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints. in Molecular Pharmaceutics
American Chemical Society (ACS)., 19(2), 710-719.
https://doi.org/10.1021/acs.molpharmaceut.1c00919

Marković O, Patel NG, Serajuddin ATM, Avdeef A, Verbić T. Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints. in Molecular Pharmaceutics. 2022;19(2):710-719.
doi:10.1021/acs.molpharmaceut.1c00919 .

Marković, Olivera, Patel, Nirali G., Serajuddin, Abu T. M., Avdeef, Alex, Verbić, Tatjana, "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints" in Molecular Pharmaceutics, 19, no. 2 (2022):710-719,
https://doi.org/10.1021/acs.molpharmaceut.1c00919 . .

TY  - CONF
AU  - Marković, Olivera S.
AU  - Gajić, Brankica P.
AU  - Pešić, Miloš P.
AU  - Verbić, Tatjana Ž.
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5396
AB  - Experimental studies of solubility are important in all phases of drug design and development. Solubility data are used to screen out drug-like candidates, biopharmaceutical classification and formulation optimization. The development of oral and parenteral dosage forms can be challenging, especially when drugs are poorly soluble, ionizable, exhibiting pH-dependent solubility and when multiple counterions are present in drug suspension. The influence of different counterions on the existing equilibria and on pH-dependent drug solubility must be defined in such systems. To investigate the effect of multiple ions on the solubility of a model basic drug – tricyclic antidepressant imipramine (Im), we conducted a systematic study of the Im solubility as a function of pH in the presence of both chloride and phosphate ions as well as in chloride-free and phosphate-free suspensions. The pH–Ramp shake–flask method1,2 was used for solubility determination. The computer program pDISOL–X was used for data analysis. It is shown that distinct pH-dependent solubility profiles were obtained in studied systems. Depending on the pH and the total concentration of chloride and/or phosphate ions, Im can precipitate as chloride and phosphate salt or free base. Furthermore, pH values of solid phase transitions (pHmax) varied as well. For instance, pHmax of solid phase transition of (ImH)H2PO4(s) to (ImH)2HPO4(s) change from 5.15 (chloride and phosphate-containing suspensions) to 5.73 (chloride-free suspensions). The intensive self-aggregation of Im in acidic region was suppressed by raising chloride or phosphate ions concentration (Iavg 1.42–1.64 M). In that way, solubility of Im was decreased due to the common-ion effect. This study illustrates the influence of competing counterions on Im solubility and on interconversions in solid phase. Hence, such factors must be taken into account during formulation optimization in drug research.
PB  - Belgrade : Serbian Chemical Society
PB  - Belgrade : Serbian Young Chemists’ Club
C3  - Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022
T1  - The influence of competing counterions on the solubility of imipramine
SP  - 27
UR  - https://hdl.handle.net/21.15107/rcub_cer_5396
ER  - 

@conference{
author = "Marković, Olivera S. and Gajić, Brankica P. and Pešić, Miloš P. and Verbić, Tatjana Ž.",
year = "2022",
abstract = "Experimental studies of solubility are important in all phases of drug design and development. Solubility data are used to screen out drug-like candidates, biopharmaceutical classification and formulation optimization. The development of oral and parenteral dosage forms can be challenging, especially when drugs are poorly soluble, ionizable, exhibiting pH-dependent solubility and when multiple counterions are present in drug suspension. The influence of different counterions on the existing equilibria and on pH-dependent drug solubility must be defined in such systems. To investigate the effect of multiple ions on the solubility of a model basic drug – tricyclic antidepressant imipramine (Im), we conducted a systematic study of the Im solubility as a function of pH in the presence of both chloride and phosphate ions as well as in chloride-free and phosphate-free suspensions. The pH–Ramp shake–flask method1,2 was used for solubility determination. The computer program pDISOL–X was used for data analysis. It is shown that distinct pH-dependent solubility profiles were obtained in studied systems. Depending on the pH and the total concentration of chloride and/or phosphate ions, Im can precipitate as chloride and phosphate salt or free base. Furthermore, pH values of solid phase transitions (pHmax) varied as well. For instance, pHmax of solid phase transition of (ImH)H2PO4(s) to (ImH)2HPO4(s) change from 5.15 (chloride and phosphate-containing suspensions) to 5.73 (chloride-free suspensions). The intensive self-aggregation of Im in acidic region was suppressed by raising chloride or phosphate ions concentration (Iavg 1.42–1.64 M). In that way, solubility of Im was decreased due to the common-ion effect. This study illustrates the influence of competing counterions on Im solubility and on interconversions in solid phase. Hence, such factors must be taken into account during formulation optimization in drug research.",
publisher = "Belgrade : Serbian Chemical Society, Belgrade : Serbian Young Chemists’ Club",
journal = "Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022",
title = "The influence of competing counterions on the solubility of imipramine",
pages = "27",
url = "https://hdl.handle.net/21.15107/rcub_cer_5396"
}

Marković, O. S., Gajić, B. P., Pešić, M. P.,& Verbić, T. Ž.. (2022). The influence of competing counterions on the solubility of imipramine. in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022
Belgrade : Serbian Chemical Society., 27.
https://hdl.handle.net/21.15107/rcub_cer_5396

Marković OS, Gajić BP, Pešić MP, Verbić TŽ. The influence of competing counterions on the solubility of imipramine. in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. 2022;:27.
https://hdl.handle.net/21.15107/rcub_cer_5396 .

Marković, Olivera S., Gajić, Brankica P., Pešić, Miloš P., Verbić, Tatjana Ž., "The influence of competing counterions on the solubility of imipramine" in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022 (2022):27,
https://hdl.handle.net/21.15107/rcub_cer_5396 .

TY  - CONF
AU  - Topalović, Igor A.
AU  - Marković, Olivera S.
AU  - Pešić, Miloš P.
AU  - Verbić, Tatjana Ž.
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5397
AB  - Nowadays, more than two-thirds of potential drugs currently being discovered are practically insoluble in water with solubility <100 μg/mL. Despite that, compounds with even lower solubility (<0.1 μg/mL) are commonly selected for further development which is very challenging, especially in the pharmaceutical formulation process1. Clofazimine (CFZ), an anti-leprosy drug with inhibitory activity against several coronaviruses, has a favourable safety profile2, but it is poorly soluble in aqueous media. Hence, it is important to develop a method for increasing its solubility. In this work, a relatively novel approach of enhancing solubility of weakly basic drugs by using weak acids that would not form salts with the drug (acid-base supersolubilization (ABS)) has been applied. CFZ aqueous solubility was determined in solutions of tartaric, citric, malic, malonic or maleic acid: in set I acid solutions had the same concentration (2.5 mol/L), and in the set II they were scaled to the same pH (1.0). The drug was added in stirred acid solution until a precipitate was noticed and, after filtration, CFZ concentration in samples was determined by HPLC. Based on set I, it was found that the solubility of CFZ had the highest value in the case of tartaric acid (0.46 mg/mL) compared to other acid solutions of the same concentration. In set II the highest CFZ concentration was determined in the malic acid solution which had the highest concentration (2.8 mol/L) among other acids. On contrary, maleic acid solution at pH=1.0 had the lowest molar concentration (0.5 mol/L) and therefore CFZ was minimally dissolved. Further research will be directed toward the examination of acid structure effect on CFZ solubility.
PB  - Belgrade : Serbian Chemical Society
PB  - Belgrade : Serbian Young Chemists’ Club
C3  - Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022
T1  - Investigation of clofazimine acid-base supersolubilization using various weak organic acids
SP  - 37
UR  - https://hdl.handle.net/21.15107/rcub_cer_5397
ER  - 

@conference{
author = "Topalović, Igor A. and Marković, Olivera S. and Pešić, Miloš P. and Verbić, Tatjana Ž.",
year = "2022",
abstract = "Nowadays, more than two-thirds of potential drugs currently being discovered are practically insoluble in water with solubility <100 μg/mL. Despite that, compounds with even lower solubility (<0.1 μg/mL) are commonly selected for further development which is very challenging, especially in the pharmaceutical formulation process1. Clofazimine (CFZ), an anti-leprosy drug with inhibitory activity against several coronaviruses, has a favourable safety profile2, but it is poorly soluble in aqueous media. Hence, it is important to develop a method for increasing its solubility. In this work, a relatively novel approach of enhancing solubility of weakly basic drugs by using weak acids that would not form salts with the drug (acid-base supersolubilization (ABS)) has been applied. CFZ aqueous solubility was determined in solutions of tartaric, citric, malic, malonic or maleic acid: in set I acid solutions had the same concentration (2.5 mol/L), and in the set II they were scaled to the same pH (1.0). The drug was added in stirred acid solution until a precipitate was noticed and, after filtration, CFZ concentration in samples was determined by HPLC. Based on set I, it was found that the solubility of CFZ had the highest value in the case of tartaric acid (0.46 mg/mL) compared to other acid solutions of the same concentration. In set II the highest CFZ concentration was determined in the malic acid solution which had the highest concentration (2.8 mol/L) among other acids. On contrary, maleic acid solution at pH=1.0 had the lowest molar concentration (0.5 mol/L) and therefore CFZ was minimally dissolved. Further research will be directed toward the examination of acid structure effect on CFZ solubility.",
publisher = "Belgrade : Serbian Chemical Society, Belgrade : Serbian Young Chemists’ Club",
journal = "Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022",
title = "Investigation of clofazimine acid-base supersolubilization using various weak organic acids",
pages = "37",
url = "https://hdl.handle.net/21.15107/rcub_cer_5397"
}

Topalović, I. A., Marković, O. S., Pešić, M. P.,& Verbić, T. Ž.. (2022). Investigation of clofazimine acid-base supersolubilization using various weak organic acids. in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022
Belgrade : Serbian Chemical Society., 37.
https://hdl.handle.net/21.15107/rcub_cer_5397

Topalović IA, Marković OS, Pešić MP, Verbić TŽ. Investigation of clofazimine acid-base supersolubilization using various weak organic acids. in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. 2022;:37.
https://hdl.handle.net/21.15107/rcub_cer_5397 .

Topalović, Igor A., Marković, Olivera S., Pešić, Miloš P., Verbić, Tatjana Ž., "Investigation of clofazimine acid-base supersolubilization using various weak organic acids" in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022 (2022):37,
https://hdl.handle.net/21.15107/rcub_cer_5397 .

TY  - CONF
AU  - Marjanović, Nemanja Ž.
AU  - Marković, Olivera S.
AU  - Pešić, Miloš P.
AU  - Verbić, Tatjana Ž.
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5401
AB  - In the modern drug research the number of practically insoluble potential drugs is increasing. Poor aqueous solubility can cause poor oral absorption and low bioavailability of drugs. Hence, solubility enhancement is considered as one of the most important challenges in the formulation and development of the dosage forms of drugs. Clofazimine (CFZ) is an antibiotic drug which is used in the treatment of tuberculosis and leprosy. It is recently shown that CFZ has inhibitory activity against certain coronaviruses and can antagonize the replication of SARS-CoV-2.1 Since CFZ is highly lipophilic molecule with extremely low solubility, it is quite a challenge to find appropriate method for CFZ solubilization. The aim of this work was to investigate the effect of methanesulfonic (MSA) and glutaric (GA) acids on the solubility of CFZ. The effect of MSA on the solubility of CFZ was studied by the pH-Ramp shake-flask method (pH-RSF).2 The solubility of CFZ was determined in the presence of GA in two ways: 1) by melting a mixture of CFZ and GA in different molar ratios, and then dissolving in water; 2) using the pH-RSF method. Interactions between CZ and GA were investigated by IR spectroscopy. It is shown that both MSA and GA increase the solubility of CFZ in acidic suspensions prepared by pH-RSF method. Also, solubility enhancement was observed in the molten CFZ-GA mixtures (molar ratio 1:1 and 1:4) compared to mixtures prepared without melting. Besides that, the IR spectra of these mixtures revealed that characteristic CFZ band was shifted in molted CFZ-GA mixture (molar ratio 1:1) probably due to CFZ-GA interactions. Preliminary results presented in this study illustrate that MSA and GA can be used for solubility improvement of CFZ.
PB  - Belgrade : Serbian Chemical Society
PB  - Belgrade : Serbian Young Chemists’ Club
C3  - Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022
T1  - The effect of methanesulfonic and glutaric acids on the solubility of clofazimine
SP  - 40
UR  - https://hdl.handle.net/21.15107/rcub_cer_5401
ER  - 

@conference{
author = "Marjanović, Nemanja Ž. and Marković, Olivera S. and Pešić, Miloš P. and Verbić, Tatjana Ž.",
year = "2022",
abstract = "In the modern drug research the number of practically insoluble potential drugs is increasing. Poor aqueous solubility can cause poor oral absorption and low bioavailability of drugs. Hence, solubility enhancement is considered as one of the most important challenges in the formulation and development of the dosage forms of drugs. Clofazimine (CFZ) is an antibiotic drug which is used in the treatment of tuberculosis and leprosy. It is recently shown that CFZ has inhibitory activity against certain coronaviruses and can antagonize the replication of SARS-CoV-2.1 Since CFZ is highly lipophilic molecule with extremely low solubility, it is quite a challenge to find appropriate method for CFZ solubilization. The aim of this work was to investigate the effect of methanesulfonic (MSA) and glutaric (GA) acids on the solubility of CFZ. The effect of MSA on the solubility of CFZ was studied by the pH-Ramp shake-flask method (pH-RSF).2 The solubility of CFZ was determined in the presence of GA in two ways: 1) by melting a mixture of CFZ and GA in different molar ratios, and then dissolving in water; 2) using the pH-RSF method. Interactions between CZ and GA were investigated by IR spectroscopy. It is shown that both MSA and GA increase the solubility of CFZ in acidic suspensions prepared by pH-RSF method. Also, solubility enhancement was observed in the molten CFZ-GA mixtures (molar ratio 1:1 and 1:4) compared to mixtures prepared without melting. Besides that, the IR spectra of these mixtures revealed that characteristic CFZ band was shifted in molted CFZ-GA mixture (molar ratio 1:1) probably due to CFZ-GA interactions. Preliminary results presented in this study illustrate that MSA and GA can be used for solubility improvement of CFZ.",
publisher = "Belgrade : Serbian Chemical Society, Belgrade : Serbian Young Chemists’ Club",
journal = "Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022",
title = "The effect of methanesulfonic and glutaric acids on the solubility of clofazimine",
pages = "40",
url = "https://hdl.handle.net/21.15107/rcub_cer_5401"
}

Marjanović, N. Ž., Marković, O. S., Pešić, M. P.,& Verbić, T. Ž.. (2022). The effect of methanesulfonic and glutaric acids on the solubility of clofazimine. in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022
Belgrade : Serbian Chemical Society., 40.
https://hdl.handle.net/21.15107/rcub_cer_5401

Marjanović NŽ, Marković OS, Pešić MP, Verbić TŽ. The effect of methanesulfonic and glutaric acids on the solubility of clofazimine. in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. 2022;:40.
https://hdl.handle.net/21.15107/rcub_cer_5401 .

Marjanović, Nemanja Ž., Marković, Olivera S., Pešić, Miloš P., Verbić, Tatjana Ž., "The effect of methanesulfonic and glutaric acids on the solubility of clofazimine" in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022 (2022):40,
https://hdl.handle.net/21.15107/rcub_cer_5401 .

TY  - CONF
AU  - Mrđinac, Jelena Ž.
AU  - Marković, Olivera S.
AU  - Pešić, Miloš P.
AU  - Verbić, Tatjana Ž.
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5398
AB  - The ionization constant (usually expressed in logarithmic form, pKa) is important physicochemical parameter which is used to characterize the acid-base chemistry of a compound. Since most drugs contain one or more ionizable functional groups, knowledge of pKa values is necessary in drug research. The most common techniques used for pKa determination are potentiometry and spectrophotometry. Potentiometry is a method of choice when ionization processes are overlapping, as in such case it is not possible to obtain the absorption spectrum of each species present in solution. The aim of this work was the comparative analysis of pKa determination using potentiometry and spectrophotometry for model compounds with overlapping ionization processes: 3-aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine. The potentiometric titrations were performed with pSOL Model 3 instrument (pION) equipped with pS software package for titration data analysis.1 Avdeef–Bucher four–parameter equation was used for electrode standardization.2 To overcome the above-mentioned limitation of spectrophotometry, the alternative approach was applied in this study. The new aminocaproate phosphate buffer (containing phosphoric and ε-aminocaproic acids) was used for the solutions preparation of the model compounds in pH range 1 – 12. This buffer has numerous advantages like UV-transparency, resistance to pH changes upon standing for several days, useful buffer capacity and constant ionic strength in the wide range of pH values. Absorption spectra were recorded according to specific procedure which was carefully designed to avoid systematic errors. Collected absorption spectra will be used for the development of the algorithm for the spectral deconvolution (using MATLAB). Such software can be very useful tool in the drug research, especially for the analysis of the compounds which pKa values cannot be determined by potentiometry.
PB  - Belgrade : Serbian Chemical Society
PB  - Belgrade : Serbian Young Chemists’ Club
C3  - Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022
T1  - Comparative analysis of ionization constants determination using spectrophotometry and potentiometry: 3-aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine
SP  - 42
UR  - https://hdl.handle.net/21.15107/rcub_cer_5398
ER  - 

@conference{
author = "Mrđinac, Jelena Ž. and Marković, Olivera S. and Pešić, Miloš P. and Verbić, Tatjana Ž.",
year = "2022",
abstract = "The ionization constant (usually expressed in logarithmic form, pKa) is important physicochemical parameter which is used to characterize the acid-base chemistry of a compound. Since most drugs contain one or more ionizable functional groups, knowledge of pKa values is necessary in drug research. The most common techniques used for pKa determination are potentiometry and spectrophotometry. Potentiometry is a method of choice when ionization processes are overlapping, as in such case it is not possible to obtain the absorption spectrum of each species present in solution. The aim of this work was the comparative analysis of pKa determination using potentiometry and spectrophotometry for model compounds with overlapping ionization processes: 3-aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine. The potentiometric titrations were performed with pSOL Model 3 instrument (pION) equipped with pS software package for titration data analysis.1 Avdeef–Bucher four–parameter equation was used for electrode standardization.2 To overcome the above-mentioned limitation of spectrophotometry, the alternative approach was applied in this study. The new aminocaproate phosphate buffer (containing phosphoric and ε-aminocaproic acids) was used for the solutions preparation of the model compounds in pH range 1 – 12. This buffer has numerous advantages like UV-transparency, resistance to pH changes upon standing for several days, useful buffer capacity and constant ionic strength in the wide range of pH values. Absorption spectra were recorded according to specific procedure which was carefully designed to avoid systematic errors. Collected absorption spectra will be used for the development of the algorithm for the spectral deconvolution (using MATLAB). Such software can be very useful tool in the drug research, especially for the analysis of the compounds which pKa values cannot be determined by potentiometry.",
publisher = "Belgrade : Serbian Chemical Society, Belgrade : Serbian Young Chemists’ Club",
journal = "Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022",
title = "Comparative analysis of ionization constants determination using spectrophotometry and potentiometry: 3-aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine",
pages = "42",
url = "https://hdl.handle.net/21.15107/rcub_cer_5398"
}

Mrđinac, J. Ž., Marković, O. S., Pešić, M. P.,& Verbić, T. Ž.. (2022). Comparative analysis of ionization constants determination using spectrophotometry and potentiometry: 3-aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine. in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022
Belgrade : Serbian Chemical Society., 42.
https://hdl.handle.net/21.15107/rcub_cer_5398

Mrđinac JŽ, Marković OS, Pešić MP, Verbić TŽ. Comparative analysis of ionization constants determination using spectrophotometry and potentiometry: 3-aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine. in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022. 2022;:42.
https://hdl.handle.net/21.15107/rcub_cer_5398 .

Mrđinac, Jelena Ž., Marković, Olivera S., Pešić, Miloš P., Verbić, Tatjana Ž., "Comparative analysis of ionization constants determination using spectrophotometry and potentiometry: 3-aminobenzoic acid, 1,3,5-benzenetricarboxylic acid and tyrosine" in Book of Abstracts - 8th Conference of Young Chemists of Serbia, Belgrade, Serbia, 29th October, 2022 (2022):42,
https://hdl.handle.net/21.15107/rcub_cer_5398 .

TY  - CONF
AU  - Marković, Olivera
AU  - Gajić, Brankica P.
AU  - Pešić, Miloš P.
AU  - Verbić, Tatjana Ž.
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5087
AB  - Cilj ovog rada bio je proučavanje ravnoteža u heterogenim sistemima tricikličnog 
antidepresiva amitriptilina (Am) koji sadrže hloride i/ili fosfate. Rastvorljivost Am u 
uslovima povećane jonske sile određena je pH–Ramp shake–flask metodom. Veća 
rastvorljivost Am u kiseloj sredini od očekivane, posledica je agregacije – analiza 
eksperimentalnih podataka pomoću programa pDISOL–XTM ukazuje na verovatno 
građenje pentamera Am5H5 5+. Kritična micelarna koncentracija i stepen disocijacije 
agregata određeni su primenom konduktometrijskih titracija. U baznoj sredini primećena je 
delimična degradacija Am. Eksperimentalno dobijeni podaci o rastvorljivosti biološki 
aktivnih supstanci i postojećim ravnotežama u heterogenim sistemima važni su u svim 
fazama dizajna i razvoja lekova.
AB  - The aim of this work was to study the equilibria in tricyclic antidepressant amitriptyline 
(Am) heterogeneous systems containing chloride and/or phosphate ions. Solubility of Am 
in high ionic strength conditions was determined using pH–Ramp shake–flask method.1, 2
Higher solubility of Am than expected in an acidic media is a consequence of self-aggregation – pentamer formation (Am5H5 5+) according to pDISOL–XTM analysis. Critical 
micelle concentration and the degree of the aggregate dissociation were determined by 
conductometric titrations. Partial degradation of Am in alkaline suspensions was observed. 
Experimental studies of solubility as well as the existing equilibria in heterogeneous 
systems of biologically active compounds are important at all stages of drug design and 
development.
PB  - Belgrade : Serbian Chemical Society
C3  - Book of Abstracts, Proceedings - 58th Meeting of the Serbian Chemical Society, Belgrade, Serbia, June 9-10, 2022 / Kratki izvodi radova, kjniga radova - 58. Savetovanje Srpskog hemijskog društva, Beograd 9. i 10. jun 2022. godine
T1  - Proučavanje ravnoteža u heterogenim sistemima tricikličnog  antidepresiva amitriptilina
T1  - Study of equilibria in heterogeneous systems of tricyclic  antidepressant amitriptyline
SP  - 53
EP  - 53
UR  - https://hdl.handle.net/21.15107/rcub_cer_5087
ER  - 

@conference{
author = "Marković, Olivera and Gajić, Brankica P. and Pešić, Miloš P. and Verbić, Tatjana Ž.",
year = "2022",
abstract = "Cilj ovog rada bio je proučavanje ravnoteža u heterogenim sistemima tricikličnog 
antidepresiva amitriptilina (Am) koji sadrže hloride i/ili fosfate. Rastvorljivost Am u 
uslovima povećane jonske sile određena je pH–Ramp shake–flask metodom. Veća 
rastvorljivost Am u kiseloj sredini od očekivane, posledica je agregacije – analiza 
eksperimentalnih podataka pomoću programa pDISOL–XTM ukazuje na verovatno 
građenje pentamera Am5H5 5+. Kritična micelarna koncentracija i stepen disocijacije 
agregata određeni su primenom konduktometrijskih titracija. U baznoj sredini primećena je 
delimična degradacija Am. Eksperimentalno dobijeni podaci o rastvorljivosti biološki 
aktivnih supstanci i postojećim ravnotežama u heterogenim sistemima važni su u svim 
fazama dizajna i razvoja lekova., The aim of this work was to study the equilibria in tricyclic antidepressant amitriptyline 
(Am) heterogeneous systems containing chloride and/or phosphate ions. Solubility of Am 
in high ionic strength conditions was determined using pH–Ramp shake–flask method.1, 2
Higher solubility of Am than expected in an acidic media is a consequence of self-aggregation – pentamer formation (Am5H5 5+) according to pDISOL–XTM analysis. Critical 
micelle concentration and the degree of the aggregate dissociation were determined by 
conductometric titrations. Partial degradation of Am in alkaline suspensions was observed. 
Experimental studies of solubility as well as the existing equilibria in heterogeneous 
systems of biologically active compounds are important at all stages of drug design and 
development.",
publisher = "Belgrade : Serbian Chemical Society",
journal = "Book of Abstracts, Proceedings - 58th Meeting of the Serbian Chemical Society, Belgrade, Serbia, June 9-10, 2022 / Kratki izvodi radova, kjniga radova - 58. Savetovanje Srpskog hemijskog društva, Beograd 9. i 10. jun 2022. godine",
title = "Proučavanje ravnoteža u heterogenim sistemima tricikličnog  antidepresiva amitriptilina, Study of equilibria in heterogeneous systems of tricyclic  antidepressant amitriptyline",
pages = "53-53",
url = "https://hdl.handle.net/21.15107/rcub_cer_5087"
}

Marković, O., Gajić, B. P., Pešić, M. P.,& Verbić, T. Ž.. (2022). Proučavanje ravnoteža u heterogenim sistemima tricikličnog  antidepresiva amitriptilina. in Book of Abstracts, Proceedings - 58th Meeting of the Serbian Chemical Society, Belgrade, Serbia, June 9-10, 2022 / Kratki izvodi radova, kjniga radova - 58. Savetovanje Srpskog hemijskog društva, Beograd 9. i 10. jun 2022. godine
Belgrade : Serbian Chemical Society., 53-53.
https://hdl.handle.net/21.15107/rcub_cer_5087

Marković O, Gajić BP, Pešić MP, Verbić TŽ. Proučavanje ravnoteža u heterogenim sistemima tricikličnog  antidepresiva amitriptilina. in Book of Abstracts, Proceedings - 58th Meeting of the Serbian Chemical Society, Belgrade, Serbia, June 9-10, 2022 / Kratki izvodi radova, kjniga radova - 58. Savetovanje Srpskog hemijskog društva, Beograd 9. i 10. jun 2022. godine. 2022;:53-53.
https://hdl.handle.net/21.15107/rcub_cer_5087 .

Marković, Olivera, Gajić, Brankica P., Pešić, Miloš P., Verbić, Tatjana Ž., "Proučavanje ravnoteža u heterogenim sistemima tricikličnog  antidepresiva amitriptilina" in Book of Abstracts, Proceedings - 58th Meeting of the Serbian Chemical Society, Belgrade, Serbia, June 9-10, 2022 / Kratki izvodi radova, kjniga radova - 58. Savetovanje Srpskog hemijskog društva, Beograd 9. i 10. jun 2022. godine (2022):53-53,
https://hdl.handle.net/21.15107/rcub_cer_5087 .

TY  - THES
AU  - Marković, Olivera
PY  - 2022
UR  - https://eteze.bg.ac.rs/application/showtheses?thesesId=8974
UR  - https://fedorabg.bg.ac.rs/fedora/get/o:28047/bdef:Content/download
UR  - https://plus.cobiss.net/cobiss/sr/sr/bib/108547593
UR  - https://nardus.mpn.gov.rs/handle/123456789/21245
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5852
AB  - Cilj ove doktorske disertacije bio je razvoj metode koja će omogućiti tačno i preciznoodređivanje termodinamičke rastvorljivosti i definisanje ravnoteža u heterogenim sistemima nekihtricikličnih antidepresiva (desipramin, nortriptilin, imipramin i amitriptilin) u prisustvu fosfata i/ilihlorida. Rastvorljivost tricikličnih antidepresiva u zavisnosti od pH vrednosti na 25±1 ⁰ C određenaje primenom pH–Ramp shake–flask metode, razvijene tokom izrade ove teze. Koncentracijejedinjenja u rastvoru određene su pomoću HPLC–UV/VIS metode. Čvrsta faza analizirana jeprimenom elementalne analize, termogravimetrijske analize, diferencijalne skenirajuće kalorimetrijei difrakcije X-zraka praha. Kritične micelarne koncentracije imipramina i amitriptilina određene suprimenom konduktometrijskih titracija. Degradacija imipramina i amitriptilina u baznoj sredinianalizirana je pomoću UV/VIS spektrofotometrije i HPLC–UV/VIS metode. Koncentracioneravnotežne konstante (Iref 0,15 M, 25 ⁰ C) – sopstvene rastvorljivosti, proizvodi rastvorljivosti soli,konstante građenja kompleksa i konstante agregacije, izračunate su pomoću programa pDISOL–XTM. Primećeno je da desipramin i nortriptilin grade katjonske i anjonske komplekse sakomponentama fosfatnog pufera, dok imipramin i amitriptilin formiraju agregate, što dovodi dopovećanja rastvorljivosti tricikličnih antidepresiva. U zavisnosti od sastava suspenzije i dizajnaeksperimenta triciklični antidepresivi talože se u obliku hloridnih ili fosfatnih soli ili umolekulskom obliku. Rezultati pokazuju da pH–Ramp shake–flask metoda ima veliki potencijal uproučavanju pH-zavisne rastvorljivosti i da u kombinaciji sa metodama za karakterizaciju čvrstefaze može biti veoma korisna u različitim fazama dizajna i razvoja lekova.
AB  - The aim of this doctoral dissetation was development of the new method for thermodynamicsolubility determination which can provide accurate and precise data and description of equilibria intricyclic antidepressant (desipramine, nortriptyline, imipramine and amitriptyline) heterogeneoussystems containing phosphate and/or chloride ions. The solubility of tricyclic antidepressant at 25±1°C as a function of pH was determined using pH–Ramp shake–flask method, developed as a resultsof this dissertation. Concentration was measured by HPLC–UV/VIS method. The solid phases werecharacterized using elemental, thermogravimetric, differential scanning calorimetric, and powder X-ray diffraction analyses. Conductivity measurements were used for critical micelle concentrationdetermination. Degradation of imipramine and amitriptyline in alkaline media was investigated byUV/VIS spectrophotometry and HPLC–UV/VIS method. Concentration thermodynamic constants(Iref 0,15 M, 25 ⁰ C) – intrinsic solubilities, solubility products, complexation and aggregationconstants, were refined using the computer program pDISOL–XTM. Cationic and anionic phosphatecomplex formation was observed in heterogeneous systems of desipramine and nortriptyline, butself–aggregation was observed in heterogeneous systems of imipramine and amitriptyline, leadingto increased solubility of tricyclic antidepressant. Depending on suspension composition andexperimental design, tricyclic antidepressant can precipite as chloride and phosphate salts or freebase. pH–Ramp shake–flask method in combination with solid state characterization methods canbe powerful technique in pH-dependent solubility investigation and can provide high-quality datathat can be useful in drug research.
PB  - Универзитет у Београду, Хемијски факултет
T2  - Универзитет у Београду
T1  - Proučavanje ravnoteža u heterogenim sistemima tricikličnih antidepresiva: uticaj agregacije i sastava čvrste faze na rastvorljivost
UR  - https://hdl.handle.net/21.15107/rcub_nardus_21245
ER  - 

@phdthesis{
author = "Marković, Olivera",
year = "2022",
abstract = "Cilj ove doktorske disertacije bio je razvoj metode koja će omogućiti tačno i preciznoodređivanje termodinamičke rastvorljivosti i definisanje ravnoteža u heterogenim sistemima nekihtricikličnih antidepresiva (desipramin, nortriptilin, imipramin i amitriptilin) u prisustvu fosfata i/ilihlorida. Rastvorljivost tricikličnih antidepresiva u zavisnosti od pH vrednosti na 25±1 ⁰ C određenaje primenom pH–Ramp shake–flask metode, razvijene tokom izrade ove teze. Koncentracijejedinjenja u rastvoru određene su pomoću HPLC–UV/VIS metode. Čvrsta faza analizirana jeprimenom elementalne analize, termogravimetrijske analize, diferencijalne skenirajuće kalorimetrijei difrakcije X-zraka praha. Kritične micelarne koncentracije imipramina i amitriptilina određene suprimenom konduktometrijskih titracija. Degradacija imipramina i amitriptilina u baznoj sredinianalizirana je pomoću UV/VIS spektrofotometrije i HPLC–UV/VIS metode. Koncentracioneravnotežne konstante (Iref 0,15 M, 25 ⁰ C) – sopstvene rastvorljivosti, proizvodi rastvorljivosti soli,konstante građenja kompleksa i konstante agregacije, izračunate su pomoću programa pDISOL–XTM. Primećeno je da desipramin i nortriptilin grade katjonske i anjonske komplekse sakomponentama fosfatnog pufera, dok imipramin i amitriptilin formiraju agregate, što dovodi dopovećanja rastvorljivosti tricikličnih antidepresiva. U zavisnosti od sastava suspenzije i dizajnaeksperimenta triciklični antidepresivi talože se u obliku hloridnih ili fosfatnih soli ili umolekulskom obliku. Rezultati pokazuju da pH–Ramp shake–flask metoda ima veliki potencijal uproučavanju pH-zavisne rastvorljivosti i da u kombinaciji sa metodama za karakterizaciju čvrstefaze može biti veoma korisna u različitim fazama dizajna i razvoja lekova., The aim of this doctoral dissetation was development of the new method for thermodynamicsolubility determination which can provide accurate and precise data and description of equilibria intricyclic antidepressant (desipramine, nortriptyline, imipramine and amitriptyline) heterogeneoussystems containing phosphate and/or chloride ions. The solubility of tricyclic antidepressant at 25±1°C as a function of pH was determined using pH–Ramp shake–flask method, developed as a resultsof this dissertation. Concentration was measured by HPLC–UV/VIS method. The solid phases werecharacterized using elemental, thermogravimetric, differential scanning calorimetric, and powder X-ray diffraction analyses. Conductivity measurements were used for critical micelle concentrationdetermination. Degradation of imipramine and amitriptyline in alkaline media was investigated byUV/VIS spectrophotometry and HPLC–UV/VIS method. Concentration thermodynamic constants(Iref 0,15 M, 25 ⁰ C) – intrinsic solubilities, solubility products, complexation and aggregationconstants, were refined using the computer program pDISOL–XTM. Cationic and anionic phosphatecomplex formation was observed in heterogeneous systems of desipramine and nortriptyline, butself–aggregation was observed in heterogeneous systems of imipramine and amitriptyline, leadingto increased solubility of tricyclic antidepressant. Depending on suspension composition andexperimental design, tricyclic antidepressant can precipite as chloride and phosphate salts or freebase. pH–Ramp shake–flask method in combination with solid state characterization methods canbe powerful technique in pH-dependent solubility investigation and can provide high-quality datathat can be useful in drug research.",
publisher = "Универзитет у Београду, Хемијски факултет",
journal = "Универзитет у Београду",
title = "Proučavanje ravnoteža u heterogenim sistemima tricikličnih antidepresiva: uticaj agregacije i sastava čvrste faze na rastvorljivost",
url = "https://hdl.handle.net/21.15107/rcub_nardus_21245"
}

Marković, O.. (2022). Proučavanje ravnoteža u heterogenim sistemima tricikličnih antidepresiva: uticaj agregacije i sastava čvrste faze na rastvorljivost. in Универзитет у Београду
Универзитет у Београду, Хемијски факултет..
https://hdl.handle.net/21.15107/rcub_nardus_21245

Marković O. Proučavanje ravnoteža u heterogenim sistemima tricikličnih antidepresiva: uticaj agregacije i sastava čvrste faze na rastvorljivost. in Универзитет у Београду. 2022;.
https://hdl.handle.net/21.15107/rcub_nardus_21245 .

Marković, Olivera, "Proučavanje ravnoteža u heterogenim sistemima tricikličnih antidepresiva: uticaj agregacije i sastava čvrste faze na rastvorljivost" in Универзитет у Београду (2022),
https://hdl.handle.net/21.15107/rcub_nardus_21245 .

TY  - JOUR
AU  - Marković, Olivera
AU  - Patel, Nirali G.
AU  - Serajuddin, Abu T. M.
AU  - Avdeef, Alex
AU  - Verbić, Tatjana
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4934
AB  - The solubility of a model basic drug, nortriptyline (Nor), was investigated as a function of pH in phosphate and/or a chloride-containing aqueous suspension using experimental practices recommended in the previously published “white paper” (Avdeef et al., 2016). The pH-Ramp Shake-Flask (pHRSF) method, introduced in our earlier work (Marković et al.,
2019), was applied. An improved and more detailed experimental
design of the Nor solubility measurement allowed us to exploit the
full capacity of the pH-RSF method. Complex equilibria in the
aqueous phase (cationic and anionic complex formation between
Nor and the phosphate) and solid-phase transformations (Nor free
base, 1:1 Nor hydrochloride salt, 1:1 and 1:2 Nor phosphate salts)
were characterized by a detailed analysis of the solubility
measurements using the computer program pDISOL-X. The solid phases were characterized by thermogravimetric analysis,
differential scanning calorimetry, powder X-ray diffraction, and elemental analyses. The results of the present investigation illustrate
the influence of competing counterions, such as buffering agents, complexing agents, salt coformers, tonicity adjusters, and so forth,
on the aqueous solubility of drugs and interconversion of salts. Careful attention given to these factors can be helpful in the
formulation of drug products.
PB  - American Chemical Society (ACS)
T2  - Molecular Pharmaceutics
T1  - Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints
VL  - 19
IS  - 2
SP  - 710
EP  - 719
DO  - 10.1021/acs.molpharmaceut.1c00919
ER  - 

@article{
author = "Marković, Olivera and Patel, Nirali G. and Serajuddin, Abu T. M. and Avdeef, Alex and Verbić, Tatjana",
year = "2022",
abstract = "The solubility of a model basic drug, nortriptyline (Nor), was investigated as a function of pH in phosphate and/or a chloride-containing aqueous suspension using experimental practices recommended in the previously published “white paper” (Avdeef et al., 2016). The pH-Ramp Shake-Flask (pHRSF) method, introduced in our earlier work (Marković et al.,
2019), was applied. An improved and more detailed experimental
design of the Nor solubility measurement allowed us to exploit the
full capacity of the pH-RSF method. Complex equilibria in the
aqueous phase (cationic and anionic complex formation between
Nor and the phosphate) and solid-phase transformations (Nor free
base, 1:1 Nor hydrochloride salt, 1:1 and 1:2 Nor phosphate salts)
were characterized by a detailed analysis of the solubility
measurements using the computer program pDISOL-X. The solid phases were characterized by thermogravimetric analysis,
differential scanning calorimetry, powder X-ray diffraction, and elemental analyses. The results of the present investigation illustrate
the influence of competing counterions, such as buffering agents, complexing agents, salt coformers, tonicity adjusters, and so forth,
on the aqueous solubility of drugs and interconversion of salts. Careful attention given to these factors can be helpful in the
formulation of drug products.",
publisher = "American Chemical Society (ACS)",
journal = "Molecular Pharmaceutics",
title = "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints",
volume = "19",
number = "2",
pages = "710-719",
doi = "10.1021/acs.molpharmaceut.1c00919"
}

Marković, O., Patel, N. G., Serajuddin, A. T. M., Avdeef, A.,& Verbić, T.. (2022). Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints. in Molecular Pharmaceutics
American Chemical Society (ACS)., 19(2), 710-719.
https://doi.org/10.1021/acs.molpharmaceut.1c00919

Marković O, Patel NG, Serajuddin ATM, Avdeef A, Verbić T. Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints. in Molecular Pharmaceutics. 2022;19(2):710-719.
doi:10.1021/acs.molpharmaceut.1c00919 .

Marković, Olivera, Patel, Nirali G., Serajuddin, Abu T. M., Avdeef, Alex, Verbić, Tatjana, "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints" in Molecular Pharmaceutics, 19, no. 2 (2022):710-719,
https://doi.org/10.1021/acs.molpharmaceut.1c00919 . .

TY  - DATA
AU  - Marković, Olivera
AU  - Patel, Nirali G.
AU  - Serajuddin, Abu T. M.
AU  - Avdeef, Alex
AU  - Verbić, Tatjana
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4935
AB  - Additional experimental details; preparation of stock suspensions for low-to-high pH and high-to-low pH titrations; titration and solubility data for titration sets 1–11; elemental analysis data from titration sets 9, 3, 6, and 7; and HPLC UV/VIS analysis─sample chromatograms and calibration diagram
PB  - American Chemical Society (ACS)
T2  - Molecular Pharmaceutics
T1  - Supporting information for: "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints"
DO  - 10.1021/acs.molpharmaceut.1c00919.s001
ER  - 

@misc{
author = "Marković, Olivera and Patel, Nirali G. and Serajuddin, Abu T. M. and Avdeef, Alex and Verbić, Tatjana",
year = "2022",
abstract = "Additional experimental details; preparation of stock suspensions for low-to-high pH and high-to-low pH titrations; titration and solubility data for titration sets 1–11; elemental analysis data from titration sets 9, 3, 6, and 7; and HPLC UV/VIS analysis─sample chromatograms and calibration diagram",
publisher = "American Chemical Society (ACS)",
journal = "Molecular Pharmaceutics",
title = "Supporting information for: "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints"",
doi = "10.1021/acs.molpharmaceut.1c00919.s001"
}

Marković, O., Patel, N. G., Serajuddin, A. T. M., Avdeef, A.,& Verbić, T.. (2022). Supporting information for: "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints". in Molecular Pharmaceutics
American Chemical Society (ACS)..
https://doi.org/10.1021/acs.molpharmaceut.1c00919.s001

Marković O, Patel NG, Serajuddin ATM, Avdeef A, Verbić T. Supporting information for: "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints". in Molecular Pharmaceutics. 2022;.
doi:10.1021/acs.molpharmaceut.1c00919.s001 .

Marković, Olivera, Patel, Nirali G., Serajuddin, Abu T. M., Avdeef, Alex, Verbić, Tatjana, "Supporting information for: "Nortriptyline Hydrochloride Solubility-pH Profiles in a Saline Phosphate Buffer: Drug-Phosphate Complexes and Multiple pHmax Domains with a Gibbs Phase Rule “Soft” Constraints"" in Molecular Pharmaceutics (2022),
https://doi.org/10.1021/acs.molpharmaceut.1c00919.s001 . .

TY  - JOUR
AU  - Dorontić, Slađana
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Mojsin, Marija
AU  - Stevanović, Milena J.
AU  - Marković, Olivera
AU  - Jovanović, Svetlana
PY  - 2022
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/5388
AB  - Large amounts of hazardous and toxic substances in the environment require non-toxic, cheap, easy, rapid, and sensitive methods for their detection. Blue luminescent graphene quantum dots (GQDs) were produced by electrochemical cleavage of graphite electrodes followed by gamma irradiation in the presence of ethylenediamine (EDA). Modified dots were able to detect metal ions (Co2+, Pd2+, Fe3+) due to photoluminescence quenching. The highest sensitivity was detected for the sample irradiated at a dose of 25 kGy. The limits of detection (LODs) were 1.79, 2.55, and 0.66 μmol L−1 for Co2+, Fe3+, and Pd2+, respectively. It was observed that GQDs irradiated at 200 kGy act as an ultra-sensitive turn-on probe for Malathion detection with LOD of 94 nmol L−1. Atomic force microscopy images proved the aggregation of GQDs in the presence of the investigated metal ions. Results obtained by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and LIVE/DEAD cytotoxicity test indicated that GQDs irradiated with EDA are not toxic towards MRC-5 cells, which makes them a promising, eco-friendly and safe material for sensing application.
PB  - Elsevier
T2  - Journal of Luminescence
T1  - Blue luminescent amino-functionalized graphene quantum dots as a responsive material for potential detection of metal ions and malathion
VL  - 252
SP  - 119311
DO  - 10.1016/j.jlumin.2022.119311
ER  - 

@article{
author = "Dorontić, Slađana and Bonasera, Aurelio and Scopelliti, Michelangelo and Mojsin, Marija and Stevanović, Milena J. and Marković, Olivera and Jovanović, Svetlana",
year = "2022",
abstract = "Large amounts of hazardous and toxic substances in the environment require non-toxic, cheap, easy, rapid, and sensitive methods for their detection. Blue luminescent graphene quantum dots (GQDs) were produced by electrochemical cleavage of graphite electrodes followed by gamma irradiation in the presence of ethylenediamine (EDA). Modified dots were able to detect metal ions (Co2+, Pd2+, Fe3+) due to photoluminescence quenching. The highest sensitivity was detected for the sample irradiated at a dose of 25 kGy. The limits of detection (LODs) were 1.79, 2.55, and 0.66 μmol L−1 for Co2+, Fe3+, and Pd2+, respectively. It was observed that GQDs irradiated at 200 kGy act as an ultra-sensitive turn-on probe for Malathion detection with LOD of 94 nmol L−1. Atomic force microscopy images proved the aggregation of GQDs in the presence of the investigated metal ions. Results obtained by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and LIVE/DEAD cytotoxicity test indicated that GQDs irradiated with EDA are not toxic towards MRC-5 cells, which makes them a promising, eco-friendly and safe material for sensing application.",
publisher = "Elsevier",
journal = "Journal of Luminescence",
title = "Blue luminescent amino-functionalized graphene quantum dots as a responsive material for potential detection of metal ions and malathion",
volume = "252",
pages = "119311",
doi = "10.1016/j.jlumin.2022.119311"
}

Dorontić, S., Bonasera, A., Scopelliti, M., Mojsin, M., Stevanović, M. J., Marković, O.,& Jovanović, S.. (2022). Blue luminescent amino-functionalized graphene quantum dots as a responsive material for potential detection of metal ions and malathion. in Journal of Luminescence
Elsevier., 252, 119311.
https://doi.org/10.1016/j.jlumin.2022.119311

Dorontić S, Bonasera A, Scopelliti M, Mojsin M, Stevanović MJ, Marković O, Jovanović S. Blue luminescent amino-functionalized graphene quantum dots as a responsive material for potential detection of metal ions and malathion. in Journal of Luminescence. 2022;252:119311.
doi:10.1016/j.jlumin.2022.119311 .

Dorontić, Slađana, Bonasera, Aurelio, Scopelliti, Michelangelo, Mojsin, Marija, Stevanović, Milena J., Marković, Olivera, Jovanović, Svetlana, "Blue luminescent amino-functionalized graphene quantum dots as a responsive material for potential detection of metal ions and malathion" in Journal of Luminescence, 252 (2022):119311,
https://doi.org/10.1016/j.jlumin.2022.119311 . .

TY  - CONF
AU  - Mrđan, Gorana
AU  - Verbić, Tatjana
AU  - Marković, Olivera
AU  - Vaštag, Đenđi
AU  - Apostolov, Suzana
AU  - Matijević, Borko
PY  - 2021
UR  - http://savremenimaterijali.info/
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4361
AB  - Carbohydrazone derivatives represent a very significant
class of compounds due to their wide biological activity. Ionization states of
functional groups present in the molecule are of vital importance for understanding
of the pharmacokinetic and pharmacodynamic properties of the
newly synthesized compounds. One of the physicochemical parameters, the
ionization constant (pKa), can be used as a molecular descriptor in order to relate
structure and activity of a compound, which may indicate further potential
application of newly synthesized derivatives. In this work, ionization
constants of thirteen monocarbohydrazone derivatives were determined using
potentiometric method, in order to obtain information about their ionization
states under certain conditions.
AB  - Деривати карбохидразона представљају веома значај-
на једињења за проучавање с обзиром да многа од њих показују веома
изражену биолошку активност. Познавање јонизационог стања функци-
оналних група присутних у молекулу је од виталног значаја за разумева-
ње фармакокинетичких и фармакодинамичких особина новосинтетиса-
них једињења. Један од важнијих физичко-хемијских параметара, кисе-
линска константа (pKa), може да послужи као молекулски дескриптор за
повезивање односа стуктуре и активности једињења, што може укази-
вати на даљу потенцијалну примену новосинтетисаних деривата. У
овом раду, применом потенциометријске методе, одређене су киселин-
ске константе за тринаест синтетисаних једињења из серије монокарбо-
хидразона у циљу добијања информација о њиховим јонизационим ста-
њима при одређеним условима.
PB  - Academy of Sciences and Arts of the Republic of Srpska / Академија наука и умјетности Републике Српске
C3  - 13th International Scientific Conference Contemporary Materials 2020, Proccedings,  Banja Luka, 11.09.2020.
T1  - Determination of ionization constants of selected monocarbohydrazone derivatives
T1  - Одређивање јонизационих константи одабраних деривата монокарбохидразона
SP  - 415
EP  - 422
UR  - https://hdl.handle.net/21.15107/rcub_cer_4361
ER  - 

@conference{
author = "Mrđan, Gorana and Verbić, Tatjana and Marković, Olivera and Vaštag, Đenđi and Apostolov, Suzana and Matijević, Borko",
year = "2021",
abstract = "Carbohydrazone derivatives represent a very significant
class of compounds due to their wide biological activity. Ionization states of
functional groups present in the molecule are of vital importance for understanding
of the pharmacokinetic and pharmacodynamic properties of the
newly synthesized compounds. One of the physicochemical parameters, the
ionization constant (pKa), can be used as a molecular descriptor in order to relate
structure and activity of a compound, which may indicate further potential
application of newly synthesized derivatives. In this work, ionization
constants of thirteen monocarbohydrazone derivatives were determined using
potentiometric method, in order to obtain information about their ionization
states under certain conditions., Деривати карбохидразона представљају веома значај-
на једињења за проучавање с обзиром да многа од њих показују веома
изражену биолошку активност. Познавање јонизационог стања функци-
оналних група присутних у молекулу је од виталног значаја за разумева-
ње фармакокинетичких и фармакодинамичких особина новосинтетиса-
них једињења. Један од важнијих физичко-хемијских параметара, кисе-
линска константа (pKa), може да послужи као молекулски дескриптор за
повезивање односа стуктуре и активности једињења, што може укази-
вати на даљу потенцијалну примену новосинтетисаних деривата. У
овом раду, применом потенциометријске методе, одређене су киселин-
ске константе за тринаест синтетисаних једињења из серије монокарбо-
хидразона у циљу добијања информација о њиховим јонизационим ста-
њима при одређеним условима.",
publisher = "Academy of Sciences and Arts of the Republic of Srpska / Академија наука и умјетности Републике Српске",
journal = "13th International Scientific Conference Contemporary Materials 2020, Proccedings,  Banja Luka, 11.09.2020.",
title = "Determination of ionization constants of selected monocarbohydrazone derivatives, Одређивање јонизационих константи одабраних деривата монокарбохидразона",
pages = "415-422",
url = "https://hdl.handle.net/21.15107/rcub_cer_4361"
}

Mrđan, G., Verbić, T., Marković, O., Vaštag, Đ., Apostolov, S.,& Matijević, B.. (2021). Determination of ionization constants of selected monocarbohydrazone derivatives. in 13th International Scientific Conference Contemporary Materials 2020, Proccedings,  Banja Luka, 11.09.2020.
Academy of Sciences and Arts of the Republic of Srpska / Академија наука и умјетности Републике Српске., 415-422.
https://hdl.handle.net/21.15107/rcub_cer_4361

Mrđan G, Verbić T, Marković O, Vaštag Đ, Apostolov S, Matijević B. Determination of ionization constants of selected monocarbohydrazone derivatives. in 13th International Scientific Conference Contemporary Materials 2020, Proccedings,  Banja Luka, 11.09.2020.. 2021;:415-422.
https://hdl.handle.net/21.15107/rcub_cer_4361 .

Mrđan, Gorana, Verbić, Tatjana, Marković, Olivera, Vaštag, Đenđi, Apostolov, Suzana, Matijević, Borko, "Determination of ionization constants of selected monocarbohydrazone derivatives" in 13th International Scientific Conference Contemporary Materials 2020, Proccedings,  Banja Luka, 11.09.2020. (2021):415-422,
https://hdl.handle.net/21.15107/rcub_cer_4361 .

TY  - CONF
AU  - Mrđan, Gorana
AU  - Vaštag, Đenđi
AU  - Apostolov, Suzana
AU  - Rašeta, Milena
AU  - Verbić, Tatjana
AU  - Marković, Olivera
AU  - Matijević, Borko
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4760
AB  - Carbohydrazones and their thio analogs represent compounds obtained by condensation of carbohydrazide and thiocarbohydrazide with carbonyl compounds. Due to their structure, relatively simple synthesis, and high reactivity, mentioned derivatives have a wide range of applications in all fields. In this study, ionization constants of four newly synthesized mono(thio)carbohydrazones were determined by applying the potentiometric method. Also, the influence of specific 
and nonspecific intermolecular interactions on maxima shifting in UV-Vis absorption spectra was investigated and quantified using the linear solvation energy relationships method and Catalan’s model. Finally, by applying the DPPH assay, the antioxidant potential of the newly synthesized compounds was determined, and thiocarbohydrazone derivatives proved to be significantly more active when compared to carbohydrazones.
C3  - Programme and the book of abstracts, 14th International Scientific Conference Contemporary Materials 2021
T1  - Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives
SP  - 40
EP  - 40
UR  - https://hdl.handle.net/21.15107/rcub_cer_4760
ER  - 

@conference{
author = "Mrđan, Gorana and Vaštag, Đenđi and Apostolov, Suzana and Rašeta, Milena and Verbić, Tatjana and Marković, Olivera and Matijević, Borko",
year = "2021",
abstract = "Carbohydrazones and their thio analogs represent compounds obtained by condensation of carbohydrazide and thiocarbohydrazide with carbonyl compounds. Due to their structure, relatively simple synthesis, and high reactivity, mentioned derivatives have a wide range of applications in all fields. In this study, ionization constants of four newly synthesized mono(thio)carbohydrazones were determined by applying the potentiometric method. Also, the influence of specific 
and nonspecific intermolecular interactions on maxima shifting in UV-Vis absorption spectra was investigated and quantified using the linear solvation energy relationships method and Catalan’s model. Finally, by applying the DPPH assay, the antioxidant potential of the newly synthesized compounds was determined, and thiocarbohydrazone derivatives proved to be significantly more active when compared to carbohydrazones.",
journal = "Programme and the book of abstracts, 14th International Scientific Conference Contemporary Materials 2021",
title = "Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives",
pages = "40-40",
url = "https://hdl.handle.net/21.15107/rcub_cer_4760"
}

Mrđan, G., Vaštag, Đ., Apostolov, S., Rašeta, M., Verbić, T., Marković, O.,& Matijević, B.. (2021). Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives. in Programme and the book of abstracts, 14th International Scientific Conference Contemporary Materials 2021, 40-40.
https://hdl.handle.net/21.15107/rcub_cer_4760

Mrđan G, Vaštag Đ, Apostolov S, Rašeta M, Verbić T, Marković O, Matijević B. Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives. in Programme and the book of abstracts, 14th International Scientific Conference Contemporary Materials 2021. 2021;:40-40.
https://hdl.handle.net/21.15107/rcub_cer_4760 .

Mrđan, Gorana, Vaštag, Đenđi, Apostolov, Suzana, Rašeta, Milena, Verbić, Tatjana, Marković, Olivera, Matijević, Borko, "Investigation of physicochemical properties and potential biological activity of 2-pyridine-(thio)carbohydrazone derivatives" in Programme and the book of abstracts, 14th International Scientific Conference Contemporary Materials 2021 (2021):40-40,
https://hdl.handle.net/21.15107/rcub_cer_4760 .

TY  - JOUR
AU  - Krunić, Matija
AU  - Ristić, Biljana
AU  - Bošnjak, Mihajlo
AU  - Paunović, Verica
AU  - Tovilović-Kovačević, Gordana
AU  - Zogović, Nevena
AU  - Mirčić, Aleksandar
AU  - Marković, Zoran
AU  - Todorović-Marković, Biljana
AU  - Jovanović, Svetlana
AU  - Kleut, Duška
AU  - Mojović, Miloš
AU  - Nakarada, Đura
AU  - Marković, Olivera
AU  - Vuković, Irena
AU  - Harhaji-Trajković, Ljubica
AU  - Trajković, Vladimir
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4812
AB  - We investigated the ability of graphene quantum dot (GQD) nanoparticles to protect SH-SY5Y human neuroblastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP).
GQD reduced SNP cytotoxicity by preventing mitochondrial depolarization, caspase-2 activation, and subsequent apoptotic death. Although GQD diminished the levels of nitric oxide (NO) in SNP-exposed cells, NO scavengers displayed only a slight protective effect, suggesting that NO quenching was not the main protective mechanism of GQD. GQD also reduced SNP-triggered increase in the intracellular levels of hydroxyl radical (•OH), superoxide anion (O2•- ), and lipid peroxidation. Nonselective antioxidants, •OH scavenging, and iron chelators, but not superoxide dismutase, mimicked GQD cytoprotective activity, indicating that GQD protect cells by neutralizing •OH generated in the presence of SNP-released iron. Cellular internalization of GQD was required for optimal protection, since a removal of extracellular GQD by extensive washing only partly diminished their protective effect. Moreover, GQD cooperated with SNP to induce autophagy, as confirmed by the inhibition of autophagylimiting Akt/PRAS40/mTOR signaling and increase in autophagy gene transcription, protein levels of proautophagic beclin-1 and LC3-II, formation of autophagic vesicles, and degradation of autophagic target p62. The antioxidant activity of GQD was not involved in autophagy induction, as antioxidants N-acetylcysteine and dimethyl sulfoxide failed to stimulate autophagy in SNP-exposed cells. Pharmacological inhibitors of early (wortmannin, 3-methyladenine) or late stages of autophagy (NH4Cl) efficiently reduced the protective effect of GQD. Therefore, the ability of GQD to prevent the in vitro neurotoxicity of SNP depends on both •OH/NO scavenging and induction of cytoprotective autophagy.
PB  - Elsevier
T2  - Free Radical Biology and Medicine
T1  - Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death
VL  - 177
SP  - 167
EP  - 180
DO  - 10.1016/j.freeradbiomed.2021.10.025
ER  - 

@article{
author = "Krunić, Matija and Ristić, Biljana and Bošnjak, Mihajlo and Paunović, Verica and Tovilović-Kovačević, Gordana and Zogović, Nevena and Mirčić, Aleksandar and Marković, Zoran and Todorović-Marković, Biljana and Jovanović, Svetlana and Kleut, Duška and Mojović, Miloš and Nakarada, Đura and Marković, Olivera and Vuković, Irena and Harhaji-Trajković, Ljubica and Trajković, Vladimir",
year = "2021",
abstract = "We investigated the ability of graphene quantum dot (GQD) nanoparticles to protect SH-SY5Y human neuroblastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP).
GQD reduced SNP cytotoxicity by preventing mitochondrial depolarization, caspase-2 activation, and subsequent apoptotic death. Although GQD diminished the levels of nitric oxide (NO) in SNP-exposed cells, NO scavengers displayed only a slight protective effect, suggesting that NO quenching was not the main protective mechanism of GQD. GQD also reduced SNP-triggered increase in the intracellular levels of hydroxyl radical (•OH), superoxide anion (O2•- ), and lipid peroxidation. Nonselective antioxidants, •OH scavenging, and iron chelators, but not superoxide dismutase, mimicked GQD cytoprotective activity, indicating that GQD protect cells by neutralizing •OH generated in the presence of SNP-released iron. Cellular internalization of GQD was required for optimal protection, since a removal of extracellular GQD by extensive washing only partly diminished their protective effect. Moreover, GQD cooperated with SNP to induce autophagy, as confirmed by the inhibition of autophagylimiting Akt/PRAS40/mTOR signaling and increase in autophagy gene transcription, protein levels of proautophagic beclin-1 and LC3-II, formation of autophagic vesicles, and degradation of autophagic target p62. The antioxidant activity of GQD was not involved in autophagy induction, as antioxidants N-acetylcysteine and dimethyl sulfoxide failed to stimulate autophagy in SNP-exposed cells. Pharmacological inhibitors of early (wortmannin, 3-methyladenine) or late stages of autophagy (NH4Cl) efficiently reduced the protective effect of GQD. Therefore, the ability of GQD to prevent the in vitro neurotoxicity of SNP depends on both •OH/NO scavenging and induction of cytoprotective autophagy.",
publisher = "Elsevier",
journal = "Free Radical Biology and Medicine",
title = "Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death",
volume = "177",
pages = "167-180",
doi = "10.1016/j.freeradbiomed.2021.10.025"
}

Krunić, M., Ristić, B., Bošnjak, M., Paunović, V., Tovilović-Kovačević, G., Zogović, N., Mirčić, A., Marković, Z., Todorović-Marković, B., Jovanović, S., Kleut, D., Mojović, M., Nakarada, Đ., Marković, O., Vuković, I., Harhaji-Trajković, L.,& Trajković, V.. (2021). Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death. in Free Radical Biology and Medicine
Elsevier., 177, 167-180.
https://doi.org/10.1016/j.freeradbiomed.2021.10.025

Krunić M, Ristić B, Bošnjak M, Paunović V, Tovilović-Kovačević G, Zogović N, Mirčić A, Marković Z, Todorović-Marković B, Jovanović S, Kleut D, Mojović M, Nakarada Đ, Marković O, Vuković I, Harhaji-Trajković L, Trajković V. Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death. in Free Radical Biology and Medicine. 2021;177:167-180.
doi:10.1016/j.freeradbiomed.2021.10.025 .

Krunić, Matija, Ristić, Biljana, Bošnjak, Mihajlo, Paunović, Verica, Tovilović-Kovačević, Gordana, Zogović, Nevena, Mirčić, Aleksandar, Marković, Zoran, Todorović-Marković, Biljana, Jovanović, Svetlana, Kleut, Duška, Mojović, Miloš, Nakarada, Đura, Marković, Olivera, Vuković, Irena, Harhaji-Trajković, Ljubica, Trajković, Vladimir, "Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death" in Free Radical Biology and Medicine, 177 (2021):167-180,
https://doi.org/10.1016/j.freeradbiomed.2021.10.025 . .

TY  - JOUR
AU  - Krunić, Matija
AU  - Ristić, Biljana
AU  - Bošnjak, Mihajlo
AU  - Paunović, Verica
AU  - Tovilović-Kovačević, Gordana
AU  - Zogović, Nevena
AU  - Mirčić, Aleksandar
AU  - Marković, Zoran
AU  - Todorović-Marković, Biljana
AU  - Jovanović, Svetlana
AU  - Kleut, Duška
AU  - Mojović, Miloš
AU  - Nakarada, Đura
AU  - Marković, Olivera
AU  - Vuković, Irena
AU  - Harhaji-Trajković, Ljubica
AU  - Trajković, Vladimir
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4818
AB  - We investigated the ability of graphene quantum dot (GQD) nanoparticles to protect SH-SY5Y human neuroblastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP).GQD reduced SNP cytotoxicity by preventing mitochondrial depolarization, caspase-2 activation, and subsequent apoptotic death. Although GQD diminished the levels of nitric oxide (NO) in SNP-exposed cells, NO scavengers displayed only a slight protective effect, suggesting that NO quenching was not the main protective mechanism of GQD. GQD also reduced SNP-triggered increase in the intracellular levels of hydroxyl radical (•OH), superoxide anion (O2•- ), and lipid peroxidation. Nonselective antioxidants, •OH scavenging, and iron chelators, but not superoxide dismutase, mimicked GQD cytoprotective activity, indicating that GQD protect cells by neutralizing •OH generated in the presence of SNP-released iron. Cellular internalization of GQD was required for optimal protection, since a removal of extracellular GQD by extensive washing only partly diminished their protective effect. Moreover, GQD cooperated with SNP to induce autophagy, as confirmed by the inhibition of autophagylimiting Akt/PRAS40/mTOR signaling and increase in autophagy gene transcription, protein levels of proautophagic beclin-1 and LC3-II, formation of autophagic vesicles, and degradation of autophagic target p62. The antioxidant activity of GQD was not involved in autophagy induction, as antioxidants N-acetylcysteine and dimethyl sulfoxide failed to stimulate autophagy in SNP-exposed cells. Pharmacological inhibitors of early (wortmannin, 3-methyladenine) or late stages of autophagy (NH4Cl) efficiently reduced the protective effect of GQD. Therefore, the ability of GQD to prevent the in vitro neurotoxicity of SNP depends on both •OH/NO scavenging and induction of cytoprotective autophagy.
PB  - Elsevier
T2  - Free Radical Biology and Medicine
T1  - Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death
VL  - 177
SP  - 167
EP  - 180
DO  - 10.1016/j.freeradbiomed.2021.10.025
ER  - 

@article{
author = "Krunić, Matija and Ristić, Biljana and Bošnjak, Mihajlo and Paunović, Verica and Tovilović-Kovačević, Gordana and Zogović, Nevena and Mirčić, Aleksandar and Marković, Zoran and Todorović-Marković, Biljana and Jovanović, Svetlana and Kleut, Duška and Mojović, Miloš and Nakarada, Đura and Marković, Olivera and Vuković, Irena and Harhaji-Trajković, Ljubica and Trajković, Vladimir",
year = "2021",
abstract = "We investigated the ability of graphene quantum dot (GQD) nanoparticles to protect SH-SY5Y human neuroblastoma cells from oxidative/nitrosative stress induced by iron-nitrosyl complex sodium nitroprusside (SNP).GQD reduced SNP cytotoxicity by preventing mitochondrial depolarization, caspase-2 activation, and subsequent apoptotic death. Although GQD diminished the levels of nitric oxide (NO) in SNP-exposed cells, NO scavengers displayed only a slight protective effect, suggesting that NO quenching was not the main protective mechanism of GQD. GQD also reduced SNP-triggered increase in the intracellular levels of hydroxyl radical (•OH), superoxide anion (O2•- ), and lipid peroxidation. Nonselective antioxidants, •OH scavenging, and iron chelators, but not superoxide dismutase, mimicked GQD cytoprotective activity, indicating that GQD protect cells by neutralizing •OH generated in the presence of SNP-released iron. Cellular internalization of GQD was required for optimal protection, since a removal of extracellular GQD by extensive washing only partly diminished their protective effect. Moreover, GQD cooperated with SNP to induce autophagy, as confirmed by the inhibition of autophagylimiting Akt/PRAS40/mTOR signaling and increase in autophagy gene transcription, protein levels of proautophagic beclin-1 and LC3-II, formation of autophagic vesicles, and degradation of autophagic target p62. The antioxidant activity of GQD was not involved in autophagy induction, as antioxidants N-acetylcysteine and dimethyl sulfoxide failed to stimulate autophagy in SNP-exposed cells. Pharmacological inhibitors of early (wortmannin, 3-methyladenine) or late stages of autophagy (NH4Cl) efficiently reduced the protective effect of GQD. Therefore, the ability of GQD to prevent the in vitro neurotoxicity of SNP depends on both •OH/NO scavenging and induction of cytoprotective autophagy.",
publisher = "Elsevier",
journal = "Free Radical Biology and Medicine",
title = "Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death",
volume = "177",
pages = "167-180",
doi = "10.1016/j.freeradbiomed.2021.10.025"
}

Krunić, M., Ristić, B., Bošnjak, M., Paunović, V., Tovilović-Kovačević, G., Zogović, N., Mirčić, A., Marković, Z., Todorović-Marković, B., Jovanović, S., Kleut, D., Mojović, M., Nakarada, Đ., Marković, O., Vuković, I., Harhaji-Trajković, L.,& Trajković, V.. (2021). Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death. in Free Radical Biology and Medicine
Elsevier., 177, 167-180.
https://doi.org/10.1016/j.freeradbiomed.2021.10.025

Krunić M, Ristić B, Bošnjak M, Paunović V, Tovilović-Kovačević G, Zogović N, Mirčić A, Marković Z, Todorović-Marković B, Jovanović S, Kleut D, Mojović M, Nakarada Đ, Marković O, Vuković I, Harhaji-Trajković L, Trajković V. Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death. in Free Radical Biology and Medicine. 2021;177:167-180.
doi:10.1016/j.freeradbiomed.2021.10.025 .

Krunić, Matija, Ristić, Biljana, Bošnjak, Mihajlo, Paunović, Verica, Tovilović-Kovačević, Gordana, Zogović, Nevena, Mirčić, Aleksandar, Marković, Zoran, Todorović-Marković, Biljana, Jovanović, Svetlana, Kleut, Duška, Mojović, Miloš, Nakarada, Đura, Marković, Olivera, Vuković, Irena, Harhaji-Trajković, Ljubica, Trajković, Vladimir, "Graphene quantum dot antioxidant and proautophagic actions protect SH-SY5Y neuroblastoma cells from oxidative stress-mediated apoptotic death" in Free Radical Biology and Medicine, 177 (2021):167-180,
https://doi.org/10.1016/j.freeradbiomed.2021.10.025 . .

TY  - JOUR
AU  - Mrđan, Gorana S.
AU  - Vastag, Gyöngyi Gy.
AU  - Škorić, Dušan
AU  - Radanović, Mirjana M.
AU  - Verbić, Tatjana
AU  - Milčić, Miloš
AU  - Stojiljković, Ivana N.
AU  - Marković, Olivera
AU  - Matijević, Borko
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4055
AB  - Derivatives of thiocarbohydrazone studied so far have shown great biological activity such as antioxidant, antimicrobial, and
anticancer.Most of these compounds are bis-substituted derivatives,while monothiocarbohydrazones are much less investigated.
Еighteen monothiocarbohydrazones were synthesized and subjected to physicochemical characterization in order to facilitate the
examination of their potential biological activity and application in future studies. The structure of synthesized derivatives was
confirmed with NMR and FT–IR spectroscopy, and with elemental analysis. For one of the compounds, single-crystal X-ray
diffraction analysis was performed. Specific and non-specific molecular interactions were interpreted by LSER principles, using
Catalan’s model. For additional information about the dominance and influence of the interactions presented, correlations with
Hansen’s solubility parameters were calculated. Influence of the type and position of the substituent on absorption maxima was
determined with LFER (linear free-energy relationship) principles, using Hammett’s equation. Acidity constants of the synthesized
compounds were theoretically calculated and experimentally determined. Moreover, the excitation of a molecule by a
photon of UV–Vis light was interpreted by time-dependent density functional theory (TD–DFT) calculations of UV absorption
bands, and intramolecular charge transfer (ICT) was quantified by calculations of the charge transfer distances (DCT).
PB  - Springer
T2  - Structural Chemistry
T1  - Synthesis, physicochemical characterization, and TD–DFT calculations of monothiocarbohydrazone derivatives
DO  - 10.1007/s11224-020-01700-y
ER  - 

@article{
author = "Mrđan, Gorana S. and Vastag, Gyöngyi Gy. and Škorić, Dušan and Radanović, Mirjana M. and Verbić, Tatjana and Milčić, Miloš and Stojiljković, Ivana N. and Marković, Olivera and Matijević, Borko",
year = "2021",
abstract = "Derivatives of thiocarbohydrazone studied so far have shown great biological activity such as antioxidant, antimicrobial, and
anticancer.Most of these compounds are bis-substituted derivatives,while monothiocarbohydrazones are much less investigated.
Еighteen monothiocarbohydrazones were synthesized and subjected to physicochemical characterization in order to facilitate the
examination of their potential biological activity and application in future studies. The structure of synthesized derivatives was
confirmed with NMR and FT–IR spectroscopy, and with elemental analysis. For one of the compounds, single-crystal X-ray
diffraction analysis was performed. Specific and non-specific molecular interactions were interpreted by LSER principles, using
Catalan’s model. For additional information about the dominance and influence of the interactions presented, correlations with
Hansen’s solubility parameters were calculated. Influence of the type and position of the substituent on absorption maxima was
determined with LFER (linear free-energy relationship) principles, using Hammett’s equation. Acidity constants of the synthesized
compounds were theoretically calculated and experimentally determined. Moreover, the excitation of a molecule by a
photon of UV–Vis light was interpreted by time-dependent density functional theory (TD–DFT) calculations of UV absorption
bands, and intramolecular charge transfer (ICT) was quantified by calculations of the charge transfer distances (DCT).",
publisher = "Springer",
journal = "Structural Chemistry",
title = "Synthesis, physicochemical characterization, and TD–DFT calculations of monothiocarbohydrazone derivatives",
doi = "10.1007/s11224-020-01700-y"
}

Mrđan, G. S., Vastag, G. Gy., Škorić, D., Radanović, M. M., Verbić, T., Milčić, M., Stojiljković, I. N., Marković, O.,& Matijević, B.. (2021). Synthesis, physicochemical characterization, and TD–DFT calculations of monothiocarbohydrazone derivatives. in Structural Chemistry
Springer..
https://doi.org/10.1007/s11224-020-01700-y

Mrđan GS, Vastag GG, Škorić D, Radanović MM, Verbić T, Milčić M, Stojiljković IN, Marković O, Matijević B. Synthesis, physicochemical characterization, and TD–DFT calculations of monothiocarbohydrazone derivatives. in Structural Chemistry. 2021;.
doi:10.1007/s11224-020-01700-y .

Mrđan, Gorana S., Vastag, Gyöngyi Gy., Škorić, Dušan, Radanović, Mirjana M., Verbić, Tatjana, Milčić, Miloš, Stojiljković, Ivana N., Marković, Olivera, Matijević, Borko, "Synthesis, physicochemical characterization, and TD–DFT calculations of monothiocarbohydrazone derivatives" in Structural Chemistry (2021),
https://doi.org/10.1007/s11224-020-01700-y . .

TY  - CONF
AU  - Marković, Olivera
AU  - Marjanović, Nemanja Ž.
AU  - Patel, Nirali
AU  - Serajuddin, Abu T. M.
AU  - Avdeef, Alex
AU  - Verbić, Tatjana
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4730
AB  - Solubility is important physicochemical parameter and determines drug stability, bioavailability and 
therapeutic action. The aim of this study was to examine solubility of nortriptyline hydrochloride in 
a wide pH range, using pH-Ramp Shake-Flask method, already applied to desipramine 
hydrochloride [1] and based of recently published recommendations [2]. Solubility was measured in phosphate buffer, in chloride-free media and phoshate-free media, using both nortriptyline base and nortriptyline hydrochloride as starting material. Elemental analysis, termogravimetric analysis, 
differential scaning calorimetric analysis and powder X-ray diffraction analysis were used for solid 
precipitate analysis.
AB  - Rastvorljivost je značajno fizičko-hemijsko svojstvo biološki aktivnih i potencijalno biološki 
aktivnih supstancija, koje određuje stabilnost, biodostupnost i terapeutsko dejstvo leka. Cilj ovog 
rada je ispitivanje rastvorljivosti nortriptilin-hidrohlorida, pomoću pH-Ramp Shake-Flask metode, 
prethodno primenjene na desipramin-hidrohlorid [1]. Eksperimenti su izvedeni prema novim 
preporukama iz literature [2]. Rastvorljivost je određena u fosfatnom puferu, u sistemu bez hlorida i 
sistemu bez fosfata, koristeći nortriptilin bazu i nortriptilin-hidrohlorid. Urađena je i katakterizacija
čvrste faze pomoću elementalne analize, termogravimetrije, diferencijalne skenirajuće kalorimetrije 
i difrakcije X-zraka.
PB  - Belgrade : Serbian Chemical Society
C3  - Book of abstracts / Proceedings 57th Meeting of the Serbian Chemical Society // Kratki izvodi radova / Knjiga radova 57. Savetovanje Srpskog hemijskog društva
T1  - pH-Dependent solubility profile of nortriptyline hydrochloride
SP  - 32
EP  - 32
UR  - https://hdl.handle.net/21.15107/rcub_cer_4730
ER  - 

@conference{
author = "Marković, Olivera and Marjanović, Nemanja Ž. and Patel, Nirali and Serajuddin, Abu T. M. and Avdeef, Alex and Verbić, Tatjana",
year = "2021",
abstract = "Solubility is important physicochemical parameter and determines drug stability, bioavailability and 
therapeutic action. The aim of this study was to examine solubility of nortriptyline hydrochloride in 
a wide pH range, using pH-Ramp Shake-Flask method, already applied to desipramine 
hydrochloride [1] and based of recently published recommendations [2]. Solubility was measured in phosphate buffer, in chloride-free media and phoshate-free media, using both nortriptyline base and nortriptyline hydrochloride as starting material. Elemental analysis, termogravimetric analysis, 
differential scaning calorimetric analysis and powder X-ray diffraction analysis were used for solid 
precipitate analysis., Rastvorljivost je značajno fizičko-hemijsko svojstvo biološki aktivnih i potencijalno biološki 
aktivnih supstancija, koje određuje stabilnost, biodostupnost i terapeutsko dejstvo leka. Cilj ovog 
rada je ispitivanje rastvorljivosti nortriptilin-hidrohlorida, pomoću pH-Ramp Shake-Flask metode, 
prethodno primenjene na desipramin-hidrohlorid [1]. Eksperimenti su izvedeni prema novim 
preporukama iz literature [2]. Rastvorljivost je određena u fosfatnom puferu, u sistemu bez hlorida i 
sistemu bez fosfata, koristeći nortriptilin bazu i nortriptilin-hidrohlorid. Urađena je i katakterizacija
čvrste faze pomoću elementalne analize, termogravimetrije, diferencijalne skenirajuće kalorimetrije 
i difrakcije X-zraka.",
publisher = "Belgrade : Serbian Chemical Society",
journal = "Book of abstracts / Proceedings 57th Meeting of the Serbian Chemical Society // Kratki izvodi radova / Knjiga radova 57. Savetovanje Srpskog hemijskog društva",
title = "pH-Dependent solubility profile of nortriptyline hydrochloride",
pages = "32-32",
url = "https://hdl.handle.net/21.15107/rcub_cer_4730"
}

Marković, O., Marjanović, N. Ž., Patel, N., Serajuddin, A. T. M., Avdeef, A.,& Verbić, T.. (2021). pH-Dependent solubility profile of nortriptyline hydrochloride. in Book of abstracts / Proceedings 57th Meeting of the Serbian Chemical Society // Kratki izvodi radova / Knjiga radova 57. Savetovanje Srpskog hemijskog društva
Belgrade : Serbian Chemical Society., 32-32.
https://hdl.handle.net/21.15107/rcub_cer_4730

Marković O, Marjanović NŽ, Patel N, Serajuddin ATM, Avdeef A, Verbić T. pH-Dependent solubility profile of nortriptyline hydrochloride. in Book of abstracts / Proceedings 57th Meeting of the Serbian Chemical Society // Kratki izvodi radova / Knjiga radova 57. Savetovanje Srpskog hemijskog društva. 2021;:32-32.
https://hdl.handle.net/21.15107/rcub_cer_4730 .

Marković, Olivera, Marjanović, Nemanja Ž., Patel, Nirali, Serajuddin, Abu T. M., Avdeef, Alex, Verbić, Tatjana, "pH-Dependent solubility profile of nortriptyline hydrochloride" in Book of abstracts / Proceedings 57th Meeting of the Serbian Chemical Society // Kratki izvodi radova / Knjiga radova 57. Savetovanje Srpskog hemijskog društva (2021):32-32,
https://hdl.handle.net/21.15107/rcub_cer_4730 .

TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera
AU  - Kleut, Duška
AU  - Jovanović, Svetlana
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4882
AB  - Graphene quantum dots (GQDs) were fabricated by simple electrochemical oxidation of 
graphite electrodes. Modified GQDs were obtained by gamma irradiation of GQDs, EDA, and 
IPA mixture at a dose of 25 kGy. In this approach, GQDs with the amino groups were produced 
(25γ-GQDs). These GQDs have shown a high uniformity, good dispersibility in water, and 
strong photoluminescence in the blue part of the electromagnetic spectrum. Modified GQDs 
were studied in the optical detection of Co2+ ions. The PL intensities of GQDs were measured 
in the presence of Co2+ ions in the concentration range 0-7.5 µmol L-1. It was demonstrated that PL intensities decreased linearly in the concentration range 0-2.5 µmol L-1. The value of the coefficient of determination (R2= 0.95949) indicates the potential of 25γ-GQDs for application 
in optical sensing of Co2+ ions.
PB  - Szeged, Hungary : University of Szeged
C3  - Proceedings - The 27th International Symposium on Analytical and  Environmental Problems
T1  - Amino functionalized graphene quantum dots - new fluorescent sensor for Co2+ ions
SP  - 107
EP  - 111
UR  - https://hdl.handle.net/21.15107/rcub_cer_4882
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera and Kleut, Duška and Jovanović, Svetlana",
year = "2021",
abstract = "Graphene quantum dots (GQDs) were fabricated by simple electrochemical oxidation of 
graphite electrodes. Modified GQDs were obtained by gamma irradiation of GQDs, EDA, and 
IPA mixture at a dose of 25 kGy. In this approach, GQDs with the amino groups were produced 
(25γ-GQDs). These GQDs have shown a high uniformity, good dispersibility in water, and 
strong photoluminescence in the blue part of the electromagnetic spectrum. Modified GQDs 
were studied in the optical detection of Co2+ ions. The PL intensities of GQDs were measured 
in the presence of Co2+ ions in the concentration range 0-7.5 µmol L-1. It was demonstrated that PL intensities decreased linearly in the concentration range 0-2.5 µmol L-1. The value of the coefficient of determination (R2= 0.95949) indicates the potential of 25γ-GQDs for application 
in optical sensing of Co2+ ions.",
publisher = "Szeged, Hungary : University of Szeged",
journal = "Proceedings - The 27th International Symposium on Analytical and  Environmental Problems",
title = "Amino functionalized graphene quantum dots - new fluorescent sensor for Co2+ ions",
pages = "107-111",
url = "https://hdl.handle.net/21.15107/rcub_cer_4882"
}

Dorontić, S., Marković, O., Kleut, D.,& Jovanović, S.. (2021). Amino functionalized graphene quantum dots - new fluorescent sensor for Co2+ ions. in Proceedings - The 27th International Symposium on Analytical and  Environmental Problems
Szeged, Hungary : University of Szeged., 107-111.
https://hdl.handle.net/21.15107/rcub_cer_4882

Dorontić S, Marković O, Kleut D, Jovanović S. Amino functionalized graphene quantum dots - new fluorescent sensor for Co2+ ions. in Proceedings - The 27th International Symposium on Analytical and  Environmental Problems. 2021;:107-111.
https://hdl.handle.net/21.15107/rcub_cer_4882 .

Dorontić, Slađana, Marković, Olivera, Kleut, Duška, Jovanović, Svetlana, "Amino functionalized graphene quantum dots - new fluorescent sensor for Co2+ ions" in Proceedings - The 27th International Symposium on Analytical and  Environmental Problems (2021):107-111,
https://hdl.handle.net/21.15107/rcub_cer_4882 .

TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera
AU  - Kleut, Duška
AU  - Jovanović, Svetlana
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4879
AB  - We produced Graphene Quantum Dots (GQDs) by electrochemical oxidation of graphite rods 
and exposed them to gamma irradiation at a dose of 200 kGy, in the presence of ethylene-diamine. Before irradiation, oxygen was removed from the GQDs dispersion by purging with Ar. These conditions induced both chemical reduction as well as the incorporation of N atoms 
in the structure of GQDs. Thus, N-doped GQDs were produced. The morphology of dots was 
investigated using atomic force microscopy. UV-Vis and photoluminescence spectroscopy 
were used to investigate the optical properties of modified GQDs. The changes in the intensities
of PL emission spectra were studied in the presence of different concentrations of Pd2+ and 
pesticide carbofuran. We observed promising results for the application of N-doped GQDs for 
non-enzymatic PL detection of selected metal ions and molecules of pesticide.
PB  - Szeged, Hungary : University of Szeged
C3  - The 27th International Symposium on Analytical and Environmental Problems
T1  - N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran
SP  - 143
EP  - 147
UR  - https://hdl.handle.net/21.15107/rcub_cer_4879
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera and Kleut, Duška and Jovanović, Svetlana",
year = "2021",
abstract = "We produced Graphene Quantum Dots (GQDs) by electrochemical oxidation of graphite rods 
and exposed them to gamma irradiation at a dose of 200 kGy, in the presence of ethylene-diamine. Before irradiation, oxygen was removed from the GQDs dispersion by purging with Ar. These conditions induced both chemical reduction as well as the incorporation of N atoms 
in the structure of GQDs. Thus, N-doped GQDs were produced. The morphology of dots was 
investigated using atomic force microscopy. UV-Vis and photoluminescence spectroscopy 
were used to investigate the optical properties of modified GQDs. The changes in the intensities
of PL emission spectra were studied in the presence of different concentrations of Pd2+ and 
pesticide carbofuran. We observed promising results for the application of N-doped GQDs for 
non-enzymatic PL detection of selected metal ions and molecules of pesticide.",
publisher = "Szeged, Hungary : University of Szeged",
journal = "The 27th International Symposium on Analytical and Environmental Problems",
title = "N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran",
pages = "143-147",
url = "https://hdl.handle.net/21.15107/rcub_cer_4879"
}

Dorontić, S., Marković, O., Kleut, D.,& Jovanović, S.. (2021). N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran. in The 27th International Symposium on Analytical and Environmental Problems
Szeged, Hungary : University of Szeged., 143-147.
https://hdl.handle.net/21.15107/rcub_cer_4879

Dorontić S, Marković O, Kleut D, Jovanović S. N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran. in The 27th International Symposium on Analytical and Environmental Problems. 2021;:143-147.
https://hdl.handle.net/21.15107/rcub_cer_4879 .

Dorontić, Slađana, Marković, Olivera, Kleut, Duška, Jovanović, Svetlana, "N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran" in The 27th International Symposium on Analytical and Environmental Problems (2021):143-147,
https://hdl.handle.net/21.15107/rcub_cer_4879 .

TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera
AU  - Kleut, Duška
AU  - Jovanović, Svetlana
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/4890
AB  - In the era of pollution and hazardous materials, new methods for the detection of pollutants
in the environment are urgently needed. Due to their specific features such as
photoluminescence (PL) in the visible part of the spectrum, dispersibility in water, and
organic solvents, nontoxicity, and biocompatibility, graphene quantum dots (GQDs) attract
attention in optical sensing of various ions and molecules. In this study, pristine graphene
quantum dots (p-GQDs) were produced in a simple single-step electrochemical top-down
approach using graphite electrodes as a starting material, and dispersion of sodium-hydroxide in 96% ethanol as a medium for electrochemical reaction. These p-GQDs were
gamma-irradiated in a dose of 25 kGy in presence of ethylenediamine in Ar medium to
introduce amino groups in their crystal lattice. Results obtained from AFM microscopy
indicate the height-uniformity of irradiated GQDs. The presence of amino groups in GQDs
was confirmed by FTIR, XPS, and UV-Vis spectroscopies. According to results obtained
from PL spectroscopy, a significant narrowing of emission band in irradiated GQDs was
observed. In further research, these GQDs were investigated as a potential PL sensor for iron
which is one of the most abundant heavy metal in the environment. In the preliminary
investigation, a water dispersion of irradiated GQDs was mixed with Fe(III) solution in
concentrations of 50 and 100 µM. Using a PL spectroscopy the PL intensity of irradiated
GQDs in presence of Fe (III) was measured. From the obtained results, it can be seen that
Fe(III) ions lead to quenching of GQDs PL intensity. Then, PL intensities were measured in
presence of Fe(III) ions in concentration range 0-100 µM. With an increase of Fe(III)
concentration, the PL intensity of GQDs decreased. It can be concluded that gamma-irradiated amino-doped GQDs have significant potential in the so-called ,,turn of“ detection
of Fe(III) ions in the aqueous medium
PB  - Belgrade, Serbia : Institute of Technical Sciences of SASA
C3  - Program and the Book of Abstracts - Nineteenth Young Researchers Conference – Materials Science and Engineering
T1  - Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions
SP  - 35
EP  - 35
UR  - https://hdl.handle.net/21.15107/rcub_cer_4890
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera and Kleut, Duška and Jovanović, Svetlana",
year = "2021",
abstract = "In the era of pollution and hazardous materials, new methods for the detection of pollutants
in the environment are urgently needed. Due to their specific features such as
photoluminescence (PL) in the visible part of the spectrum, dispersibility in water, and
organic solvents, nontoxicity, and biocompatibility, graphene quantum dots (GQDs) attract
attention in optical sensing of various ions and molecules. In this study, pristine graphene
quantum dots (p-GQDs) were produced in a simple single-step electrochemical top-down
approach using graphite electrodes as a starting material, and dispersion of sodium-hydroxide in 96% ethanol as a medium for electrochemical reaction. These p-GQDs were
gamma-irradiated in a dose of 25 kGy in presence of ethylenediamine in Ar medium to
introduce amino groups in their crystal lattice. Results obtained from AFM microscopy
indicate the height-uniformity of irradiated GQDs. The presence of amino groups in GQDs
was confirmed by FTIR, XPS, and UV-Vis spectroscopies. According to results obtained
from PL spectroscopy, a significant narrowing of emission band in irradiated GQDs was
observed. In further research, these GQDs were investigated as a potential PL sensor for iron
which is one of the most abundant heavy metal in the environment. In the preliminary
investigation, a water dispersion of irradiated GQDs was mixed with Fe(III) solution in
concentrations of 50 and 100 µM. Using a PL spectroscopy the PL intensity of irradiated
GQDs in presence of Fe (III) was measured. From the obtained results, it can be seen that
Fe(III) ions lead to quenching of GQDs PL intensity. Then, PL intensities were measured in
presence of Fe(III) ions in concentration range 0-100 µM. With an increase of Fe(III)
concentration, the PL intensity of GQDs decreased. It can be concluded that gamma-irradiated amino-doped GQDs have significant potential in the so-called ,,turn of“ detection
of Fe(III) ions in the aqueous medium",
publisher = "Belgrade, Serbia : Institute of Technical Sciences of SASA",
journal = "Program and the Book of Abstracts - Nineteenth Young Researchers Conference – Materials Science and Engineering",
title = "Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions",
pages = "35-35",
url = "https://hdl.handle.net/21.15107/rcub_cer_4890"
}

Dorontić, S., Marković, O., Kleut, D.,& Jovanović, S.. (2021). Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions. in Program and the Book of Abstracts - Nineteenth Young Researchers Conference – Materials Science and Engineering
Belgrade, Serbia : Institute of Technical Sciences of SASA., 35-35.
https://hdl.handle.net/21.15107/rcub_cer_4890

Dorontić S, Marković O, Kleut D, Jovanović S. Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions. in Program and the Book of Abstracts - Nineteenth Young Researchers Conference – Materials Science and Engineering. 2021;:35-35.
https://hdl.handle.net/21.15107/rcub_cer_4890 .

Dorontić, Slađana, Marković, Olivera, Kleut, Duška, Jovanović, Svetlana, "Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions" in Program and the Book of Abstracts - Nineteenth Young Researchers Conference – Materials Science and Engineering (2021):35-35,
https://hdl.handle.net/21.15107/rcub_cer_4890 .

TY  - CONF
AU  - Mrđan, Gorana
AU  - Verbić, Tatjana
AU  - Marković, Olivera
AU  - Matijević, Borko
AU  - Vaštag, Đenđi
AU  - Apostolov, Suzana
PY  - 2020
UR  - http://savremenimaterijali.info/
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/3688
AB  - Carbohydrazone derivatives represent a very significant class of compounds due to their wide biological activity. Ionization states of functional groups present in the molecule are of vital importance for understanding of the pharmacokinetic and pharmacodynamic properties of the newly synthesized compounds. One of the physicochemical parameters, the ionization constant (pKa), can be used as a molecular descriptor in order to relate structure and activity of a compound, which may indicate further potential application of newly synthesized derivatives. In this work, ionization constants of twenty monocarbohydrazone derivatives were determined using potentiometric method, in order to obtain information about their ionization states under certain conditions.
PB  - Academy of Sciences and Arts of the Republic of Srpska
C3  - 13th International Scientific Conference Contemporary Materials 2020, Programme and the Book of Abstracts, 11.09.2020.
T1  - Determination of ionization constants of selected monocarbohydrazone derivatives
SP  - 50
EP  - 50
UR  - https://hdl.handle.net/21.15107/rcub_cer_3688
ER  - 

@conference{
author = "Mrđan, Gorana and Verbić, Tatjana and Marković, Olivera and Matijević, Borko and Vaštag, Đenđi and Apostolov, Suzana",
year = "2020",
abstract = "Carbohydrazone derivatives represent a very significant class of compounds due to their wide biological activity. Ionization states of functional groups present in the molecule are of vital importance for understanding of the pharmacokinetic and pharmacodynamic properties of the newly synthesized compounds. One of the physicochemical parameters, the ionization constant (pKa), can be used as a molecular descriptor in order to relate structure and activity of a compound, which may indicate further potential application of newly synthesized derivatives. In this work, ionization constants of twenty monocarbohydrazone derivatives were determined using potentiometric method, in order to obtain information about their ionization states under certain conditions.",
publisher = "Academy of Sciences and Arts of the Republic of Srpska",
journal = "13th International Scientific Conference Contemporary Materials 2020, Programme and the Book of Abstracts, 11.09.2020.",
title = "Determination of ionization constants of selected monocarbohydrazone derivatives",
pages = "50-50",
url = "https://hdl.handle.net/21.15107/rcub_cer_3688"
}

Mrđan, G., Verbić, T., Marković, O., Matijević, B., Vaštag, Đ.,& Apostolov, S.. (2020). Determination of ionization constants of selected monocarbohydrazone derivatives. in 13th International Scientific Conference Contemporary Materials 2020, Programme and the Book of Abstracts, 11.09.2020.
Academy of Sciences and Arts of the Republic of Srpska., 50-50.
https://hdl.handle.net/21.15107/rcub_cer_3688

Mrđan G, Verbić T, Marković O, Matijević B, Vaštag Đ, Apostolov S. Determination of ionization constants of selected monocarbohydrazone derivatives. in 13th International Scientific Conference Contemporary Materials 2020, Programme and the Book of Abstracts, 11.09.2020.. 2020;:50-50.
https://hdl.handle.net/21.15107/rcub_cer_3688 .

Mrđan, Gorana, Verbić, Tatjana, Marković, Olivera, Matijević, Borko, Vaštag, Đenđi, Apostolov, Suzana, "Determination of ionization constants of selected monocarbohydrazone derivatives" in 13th International Scientific Conference Contemporary Materials 2020, Programme and the Book of Abstracts, 11.09.2020. (2020):50-50,
https://hdl.handle.net/21.15107/rcub_cer_3688 .