TY  - JOUR
AU  - Radulović, Valentina
AU  - Ivković, Branka
AU  - Bogavac-Stanojević, Nataša
AU  - Karljiković-Rajić, Katarina
PY  - 2020
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3708
AB  - The background of this study was transfer assessment for H3BO3 assays according to different pharmacopoeias’ monographs and verification of the crucial parameters—the polyols’ excess (mannitol, glycerine, sorbitol), the initial H3BO3 concentrations and the indicator’s concentrations. The purpose of the work was the comparative study according to different pharmacopoeias: the European (EP 9), the American (USP 35-NF 30), the Japanese (JP XVII), important for quality control of H3BO3, as an active component or an excipient. pH analyses were set up to establish the effects of selected polyols and the initial H3BO3 concentrations. For evaluation of assay results and methods’ equivalence, standard t test and two one-sided t test (TOST) were applied. Pharmacopoeias’ procedures propose volumetric analyses by 1 M NaOH standard solution with visual end-point detection (phenolphthalein) using sufficiently high H3BO3 concentrations and less excess of polyols, as the good alternative to potentiometric method. The influence of phenolphthalein’s concentration (0.1%, 1%), evidenced as relevant factor, caused the difference shown by standard t test: 99.82% (EP 9) and 99.66% (JP XVII). Equivalences between three methods were confirmed by TOST procedures with defined acceptance criterion ± 2% derived from the mean value (99.83%). The comparative study results pointed out that the initial phenolphthalein’s concentration was the crucial influencing factor on harmonization of assay mean values, which was confirmed by TOST application for the methods’ equivalency in method transfer evaluation. The best possible correlation between the lowest excess of polyol-sorbitol and the highest initial boric acid concentration was proved by JP XVII, which was indicated by pH-metric analyses. Graphic abstract: [Figure not available: see fulltext.]
PB  - Springer  Nature
T2  - Chemical Papers
T1  - Method transfer assessment for boric acid assays according to different pharmacopoeias' monographs
DO  - 10.1007/s11696-020-01377-x
ER  - 

@article{
author = "Radulović, Valentina and Ivković, Branka and Bogavac-Stanojević, Nataša and Karljiković-Rajić, Katarina",
year = "2020",
abstract = "The background of this study was transfer assessment for H3BO3 assays according to different pharmacopoeias’ monographs and verification of the crucial parameters—the polyols’ excess (mannitol, glycerine, sorbitol), the initial H3BO3 concentrations and the indicator’s concentrations. The purpose of the work was the comparative study according to different pharmacopoeias: the European (EP 9), the American (USP 35-NF 30), the Japanese (JP XVII), important for quality control of H3BO3, as an active component or an excipient. pH analyses were set up to establish the effects of selected polyols and the initial H3BO3 concentrations. For evaluation of assay results and methods’ equivalence, standard t test and two one-sided t test (TOST) were applied. Pharmacopoeias’ procedures propose volumetric analyses by 1 M NaOH standard solution with visual end-point detection (phenolphthalein) using sufficiently high H3BO3 concentrations and less excess of polyols, as the good alternative to potentiometric method. The influence of phenolphthalein’s concentration (0.1%, 1%), evidenced as relevant factor, caused the difference shown by standard t test: 99.82% (EP 9) and 99.66% (JP XVII). Equivalences between three methods were confirmed by TOST procedures with defined acceptance criterion ± 2% derived from the mean value (99.83%). The comparative study results pointed out that the initial phenolphthalein’s concentration was the crucial influencing factor on harmonization of assay mean values, which was confirmed by TOST application for the methods’ equivalency in method transfer evaluation. The best possible correlation between the lowest excess of polyol-sorbitol and the highest initial boric acid concentration was proved by JP XVII, which was indicated by pH-metric analyses. Graphic abstract: [Figure not available: see fulltext.]",
publisher = "Springer  Nature",
journal = "Chemical Papers",
title = "Method transfer assessment for boric acid assays according to different pharmacopoeias' monographs",
doi = "10.1007/s11696-020-01377-x"
}

Radulović, V., Ivković, B., Bogavac-Stanojević, N.,& Karljiković-Rajić, K.. (2020). Method transfer assessment for boric acid assays according to different pharmacopoeias' monographs. in Chemical Papers
Springer  Nature..
https://doi.org/10.1007/s11696-020-01377-x

Radulović V, Ivković B, Bogavac-Stanojević N, Karljiković-Rajić K. Method transfer assessment for boric acid assays according to different pharmacopoeias' monographs. in Chemical Papers. 2020;.
doi:10.1007/s11696-020-01377-x .

Radulović, Valentina, Ivković, Branka, Bogavac-Stanojević, Nataša, Karljiković-Rajić, Katarina, "Method transfer assessment for boric acid assays according to different pharmacopoeias' monographs" in Chemical Papers (2020),
https://doi.org/10.1007/s11696-020-01377-x . .

TY  - JOUR
AU  - Radulović, Valentina
AU  - Aleksić, Mara
AU  - Kapetanović, Vera
AU  - Rajić, K.K
AU  - Jovanović, M
AU  - Marjanović, I
AU  - Stojković, M
AU  - Agbaba, Danica
PY  - 2019
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3286
AB  - A novel voltammetric method was developed for brimonidine (BRIM) determination in deproteinized aqueous humor, simplifying preparation of biological samples for analysis for stability studies. The differential pulse voltammetric (DPV) method using boron doped diamond electrode (BDDE), based on characteristic oxidation peaks, was proposed and successfully applied. The linearity range was within 5.0 × 10−6 to 5.0 × 10−5 M of brimonidine, and limit of detection and limit of quantitation were 1.94 × 10−6 M and 6.46 × 10−6 M, respectively. Intra-day and inter-day precision and accuracy were evaluated and all results were in accordance with validation ICH guidelines. The best short-term stability study results were obtained for a concentration level of 3.0 × 10−5 M expressed by deviation of + 1.86% between initial and post storage concentrations. A long-term stability study was performed for two concentrations of 3.0 × 10−5 M and 5.0 × 10−5 M and resulted in deviations of + 1.63% and + 3.56%, respectively. A freeze and thaw stability study indicated that samples might be frozen only once. The enhancement of DPV/BDDE method sensitivity gained by modification, for the analysis of immeasurable BRIM quantities in native, untreated aqueous humor, was reached for quantities of 6 or 12 nmol/0.1 mL aqueous humor with acceptable accuracy (up to + 7.5%). The nature of the process—the irreversible one electron oxidation voltammetric peak of BRIM—limited the sensitivity. Only electrochemical pre-treatment of the BDD electrode before each measurement significantly speeded up the whole procedure. The advantages of the proposed method are simplicity, short-time performance, and good specificity/selectivity, as well as satisfactory accuracy, and no chemical modification of BDDE was necessary.
PB  - Springer Verlag
T2  - Analytical and Bioanalytical Chemistry
T1  - The evaluation of short- and long-term stability studies for brimonidine in aqueous humor by DPV/BDDE method—possible application for direct assay in native samples
DO  - 10.1007/s00216-019-01955-3
ER  - 

@article{
author = "Radulović, Valentina and Aleksić, Mara and Kapetanović, Vera and Rajić, K.K and Jovanović, M and Marjanović, I and Stojković, M and Agbaba, Danica",
year = "2019",
abstract = "A novel voltammetric method was developed for brimonidine (BRIM) determination in deproteinized aqueous humor, simplifying preparation of biological samples for analysis for stability studies. The differential pulse voltammetric (DPV) method using boron doped diamond electrode (BDDE), based on characteristic oxidation peaks, was proposed and successfully applied. The linearity range was within 5.0 × 10−6 to 5.0 × 10−5 M of brimonidine, and limit of detection and limit of quantitation were 1.94 × 10−6 M and 6.46 × 10−6 M, respectively. Intra-day and inter-day precision and accuracy were evaluated and all results were in accordance with validation ICH guidelines. The best short-term stability study results were obtained for a concentration level of 3.0 × 10−5 M expressed by deviation of + 1.86% between initial and post storage concentrations. A long-term stability study was performed for two concentrations of 3.0 × 10−5 M and 5.0 × 10−5 M and resulted in deviations of + 1.63% and + 3.56%, respectively. A freeze and thaw stability study indicated that samples might be frozen only once. The enhancement of DPV/BDDE method sensitivity gained by modification, for the analysis of immeasurable BRIM quantities in native, untreated aqueous humor, was reached for quantities of 6 or 12 nmol/0.1 mL aqueous humor with acceptable accuracy (up to + 7.5%). The nature of the process—the irreversible one electron oxidation voltammetric peak of BRIM—limited the sensitivity. Only electrochemical pre-treatment of the BDD electrode before each measurement significantly speeded up the whole procedure. The advantages of the proposed method are simplicity, short-time performance, and good specificity/selectivity, as well as satisfactory accuracy, and no chemical modification of BDDE was necessary.",
publisher = "Springer Verlag",
journal = "Analytical and Bioanalytical Chemistry",
title = "The evaluation of short- and long-term stability studies for brimonidine in aqueous humor by DPV/BDDE method—possible application for direct assay in native samples",
doi = "10.1007/s00216-019-01955-3"
}

Radulović, V., Aleksić, M., Kapetanović, V., Rajić, K.K, Jovanović, M., Marjanović, I., Stojković, M.,& Agbaba, D.. (2019). The evaluation of short- and long-term stability studies for brimonidine in aqueous humor by DPV/BDDE method—possible application for direct assay in native samples. in Analytical and Bioanalytical Chemistry
Springer Verlag..
https://doi.org/10.1007/s00216-019-01955-3

Radulović V, Aleksić M, Kapetanović V, Rajić K, Jovanović M, Marjanović I, Stojković M, Agbaba D. The evaluation of short- and long-term stability studies for brimonidine in aqueous humor by DPV/BDDE method—possible application for direct assay in native samples. in Analytical and Bioanalytical Chemistry. 2019;.
doi:10.1007/s00216-019-01955-3 .

Radulović, Valentina, Aleksić, Mara, Kapetanović, Vera, Rajić, K.K, Jovanović, M, Marjanović, I, Stojković, M, Agbaba, Danica, "The evaluation of short- and long-term stability studies for brimonidine in aqueous humor by DPV/BDDE method—possible application for direct assay in native samples" in Analytical and Bioanalytical Chemistry (2019),
https://doi.org/10.1007/s00216-019-01955-3 . .

TY  - THES
AU  - Radulović, Valentina
PY  - 2017
UR  - http://eteze.bg.ac.rs/application/showtheses?thesesId=5336
UR  - https://fedorabg.bg.ac.rs/fedora/get/o:16587/bdef:Content/download
UR  - http://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=49497103
UR  - http://nardus.mpn.gov.rs/123456789/8844
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/3407
AB  - U ovoj doktorskoj disertaciji ispitano je elektrohemijsko ponašanje vareniklina ibrimonidina, razvijene su elektroanalitičke metode za njihovo određivanje u određenimmatriksima, a ispitana je i potencijalna interakcija vareniklina i DNK...
PB  - Универзитет у Београду, Фармацеутски факултет
T2  - Универзитет у Београду
T1  - Elektrohemijsko proučavanje vareniklina i brimonidina, i razvoj elektroanalitičkih metoda za njihovo određivanje u različitim matriksima
UR  - https://hdl.handle.net/21.15107/rcub_nardus_8844
ER  - 

@phdthesis{
author = "Radulović, Valentina",
year = "2017",
abstract = "U ovoj doktorskoj disertaciji ispitano je elektrohemijsko ponašanje vareniklina ibrimonidina, razvijene su elektroanalitičke metode za njihovo određivanje u određenimmatriksima, a ispitana je i potencijalna interakcija vareniklina i DNK...",
publisher = "Универзитет у Београду, Фармацеутски факултет",
journal = "Универзитет у Београду",
title = "Elektrohemijsko proučavanje vareniklina i brimonidina, i razvoj elektroanalitičkih metoda za njihovo određivanje u različitim matriksima",
url = "https://hdl.handle.net/21.15107/rcub_nardus_8844"
}

Radulović, V.. (2017). Elektrohemijsko proučavanje vareniklina i brimonidina, i razvoj elektroanalitičkih metoda za njihovo određivanje u različitim matriksima. in Универзитет у Београду
Универзитет у Београду, Фармацеутски факултет..
https://hdl.handle.net/21.15107/rcub_nardus_8844

Radulović V. Elektrohemijsko proučavanje vareniklina i brimonidina, i razvoj elektroanalitičkih metoda za njihovo određivanje u različitim matriksima. in Универзитет у Београду. 2017;.
https://hdl.handle.net/21.15107/rcub_nardus_8844 .

Radulović, Valentina, "Elektrohemijsko proučavanje vareniklina i brimonidina, i razvoj elektroanalitičkih metoda za njihovo određivanje u različitim matriksima" in Универзитет у Београду (2017),
https://hdl.handle.net/21.15107/rcub_nardus_8844 .

TY  - JOUR
AU  - Aleksić, Mara
AU  - Radulović, Valentina
AU  - Agbaba, Danica
AU  - Kapetanović, Vera
PY  - 2013
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/1979
AB  - The electrochemical behavior of brimonidine (BRIM), an antiglaucoma agent applied in therapy for lowering high intraocular pressure, was investigated by cyclic voltammetry, differential pulse voltammetry and square wave voltammetry using a glassy carbon electrode (GCE). The reduction of BRIM occurs as one-step quasi-reversible reaction in acid and neutral medium, reaching the full reversibility in alkaline solutions. Reduction process involves the transfer of two electrons and two protons at the pyrazine ring of quinoxaline moiety, forming a dihydro-derivative. In acid and neutral solutions, brimonidine reduction product is partly oxidized to its hydroxy-derivative. BRIM is also oxidized irreversibly with the transfer of one electron and one proton at secondary amine moiety. The effects of pH of the electrolyte solution, scan rate and BRIM concentration were monitored. The nature of the electrode process was found to be controlled by the adsorption at pH > 6 and the total surface concentration of brimonidine adsorbed onto the GCE surface at pH 7, Gamma(BRIM) = 1.35 x 10(-10) mol cm(-2) was obtained. Based on this study, differential pulse voltammetric method was developed, validated and suggested for rapid electroanalytical determination of the low concentration of brimonidine. The linearity was achieved within the concentration range from 5 x 10(-7) to 5 x 10(-6) M with LOD = 1.6 x 10(-7) M and LOQ = 5.3 x 10(-7) M. The method was applied for brimonidine determination in pharmaceutical dosage form, eye drops.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Electrochimica Acta
T1  - An extensive study of electrochemical behavior of brimonidine and its determination at glassy carbon electrode
VL  - 106
SP  - 75
EP  - 81
DO  - 10.1016/j.electacta.2013.05.053
ER  - 

@article{
author = "Aleksić, Mara and Radulović, Valentina and Agbaba, Danica and Kapetanović, Vera",
year = "2013",
abstract = "The electrochemical behavior of brimonidine (BRIM), an antiglaucoma agent applied in therapy for lowering high intraocular pressure, was investigated by cyclic voltammetry, differential pulse voltammetry and square wave voltammetry using a glassy carbon electrode (GCE). The reduction of BRIM occurs as one-step quasi-reversible reaction in acid and neutral medium, reaching the full reversibility in alkaline solutions. Reduction process involves the transfer of two electrons and two protons at the pyrazine ring of quinoxaline moiety, forming a dihydro-derivative. In acid and neutral solutions, brimonidine reduction product is partly oxidized to its hydroxy-derivative. BRIM is also oxidized irreversibly with the transfer of one electron and one proton at secondary amine moiety. The effects of pH of the electrolyte solution, scan rate and BRIM concentration were monitored. The nature of the electrode process was found to be controlled by the adsorption at pH > 6 and the total surface concentration of brimonidine adsorbed onto the GCE surface at pH 7, Gamma(BRIM) = 1.35 x 10(-10) mol cm(-2) was obtained. Based on this study, differential pulse voltammetric method was developed, validated and suggested for rapid electroanalytical determination of the low concentration of brimonidine. The linearity was achieved within the concentration range from 5 x 10(-7) to 5 x 10(-6) M with LOD = 1.6 x 10(-7) M and LOQ = 5.3 x 10(-7) M. The method was applied for brimonidine determination in pharmaceutical dosage form, eye drops.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Electrochimica Acta",
title = "An extensive study of electrochemical behavior of brimonidine and its determination at glassy carbon electrode",
volume = "106",
pages = "75-81",
doi = "10.1016/j.electacta.2013.05.053"
}

Aleksić, M., Radulović, V., Agbaba, D.,& Kapetanović, V.. (2013). An extensive study of electrochemical behavior of brimonidine and its determination at glassy carbon electrode. in Electrochimica Acta
Pergamon-Elsevier Science Ltd, Oxford., 106, 75-81.
https://doi.org/10.1016/j.electacta.2013.05.053

Aleksić M, Radulović V, Agbaba D, Kapetanović V. An extensive study of electrochemical behavior of brimonidine and its determination at glassy carbon electrode. in Electrochimica Acta. 2013;106:75-81.
doi:10.1016/j.electacta.2013.05.053 .

Aleksić, Mara, Radulović, Valentina, Agbaba, Danica, Kapetanović, Vera, "An extensive study of electrochemical behavior of brimonidine and its determination at glassy carbon electrode" in Electrochimica Acta, 106 (2013):75-81,
https://doi.org/10.1016/j.electacta.2013.05.053 . .

TY  - JOUR
AU  - Radulović, Valentina
AU  - Aleksić, Mara
AU  - Agbaba, Danica
AU  - Kapetanović, Vera
PY  - 2013
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/1951
AB  - An extensive electrochemical study of brimonidine at boron doped diamond electrode (BDDE) was done by applying cyclic voltammetry (CV) and square-wave voltammetry (SWV) in sulfuric acid of different concentrations (pH ranged from 0.6 to 1.6), and in BR buffer (pH ranged from 2.0 to 9.0). It was found that the reduction of brimonidine occurred in a one-step quasi-reversible mechanism, involving the transfer of two electrons and two protons. The reduction process took place at the quinoxaline ring and the corresponding mechanism of reduction was confirmed to be the same as for the other quinoxaline derivatives. The nature of the electrode process was found to be diffusion controlled in acid medium, while in a more alkaline medium a certain degree of adsorption was noticed. Based on this study, two sensitive voltammetric methods, differential pulse (DPV) and square wave (SWV) were developed, fully validated and suggested for rapid electroanalytical determination of low concentrations of brimonidine. The linearity was achieved within the concentration range from 2x10-6 M to 3x10-5 M for DPV (LOD=6.31x10-7 M, LOQ=2.1x10-6 M) and from 5x10-7 M to 1.5x10-5 M for SWV (LOD=1.28x10-7 M, LOQ=4.28x10-7 M). The methods were applied for brimonidine determination in pharmaceutical dosage form, eye drops. The obtained good recoveries suggested these simple and accurate methods for quality control of brimonidine in dosage form. Due to its high sensitivity, the SWV method could be a good alternative for determination of low concentrations of brimonidine, even in biological samples.
PB  - Wiley-VCH Verlag GMBH, Weinheim
T2  - Electroanalysis
T1  - An Electroanalytical Approach to Brimonidine at Boron Doped Diamond Electrode Based on Its Extensive Voltammetric Study
VL  - 25
IS  - 1
SP  - 230
EP  - 236
DO  - 10.1002/elan.201200400
ER  - 

@article{
author = "Radulović, Valentina and Aleksić, Mara and Agbaba, Danica and Kapetanović, Vera",
year = "2013",
abstract = "An extensive electrochemical study of brimonidine at boron doped diamond electrode (BDDE) was done by applying cyclic voltammetry (CV) and square-wave voltammetry (SWV) in sulfuric acid of different concentrations (pH ranged from 0.6 to 1.6), and in BR buffer (pH ranged from 2.0 to 9.0). It was found that the reduction of brimonidine occurred in a one-step quasi-reversible mechanism, involving the transfer of two electrons and two protons. The reduction process took place at the quinoxaline ring and the corresponding mechanism of reduction was confirmed to be the same as for the other quinoxaline derivatives. The nature of the electrode process was found to be diffusion controlled in acid medium, while in a more alkaline medium a certain degree of adsorption was noticed. Based on this study, two sensitive voltammetric methods, differential pulse (DPV) and square wave (SWV) were developed, fully validated and suggested for rapid electroanalytical determination of low concentrations of brimonidine. The linearity was achieved within the concentration range from 2x10-6 M to 3x10-5 M for DPV (LOD=6.31x10-7 M, LOQ=2.1x10-6 M) and from 5x10-7 M to 1.5x10-5 M for SWV (LOD=1.28x10-7 M, LOQ=4.28x10-7 M). The methods were applied for brimonidine determination in pharmaceutical dosage form, eye drops. The obtained good recoveries suggested these simple and accurate methods for quality control of brimonidine in dosage form. Due to its high sensitivity, the SWV method could be a good alternative for determination of low concentrations of brimonidine, even in biological samples.",
publisher = "Wiley-VCH Verlag GMBH, Weinheim",
journal = "Electroanalysis",
title = "An Electroanalytical Approach to Brimonidine at Boron Doped Diamond Electrode Based on Its Extensive Voltammetric Study",
volume = "25",
number = "1",
pages = "230-236",
doi = "10.1002/elan.201200400"
}

Radulović, V., Aleksić, M., Agbaba, D.,& Kapetanović, V.. (2013). An Electroanalytical Approach to Brimonidine at Boron Doped Diamond Electrode Based on Its Extensive Voltammetric Study. in Electroanalysis
Wiley-VCH Verlag GMBH, Weinheim., 25(1), 230-236.
https://doi.org/10.1002/elan.201200400

Radulović V, Aleksić M, Agbaba D, Kapetanović V. An Electroanalytical Approach to Brimonidine at Boron Doped Diamond Electrode Based on Its Extensive Voltammetric Study. in Electroanalysis. 2013;25(1):230-236.
doi:10.1002/elan.201200400 .

Radulović, Valentina, Aleksić, Mara, Agbaba, Danica, Kapetanović, Vera, "An Electroanalytical Approach to Brimonidine at Boron Doped Diamond Electrode Based on Its Extensive Voltammetric Study" in Electroanalysis, 25, no. 1 (2013):230-236,
https://doi.org/10.1002/elan.201200400 . .

TY  - JOUR
AU  - Radulović, Valentina
AU  - Aleksić, Mara
AU  - Kapetanović, Vera
PY  - 2012
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/1817
AB  - The electrochemical behaviour of a novel nicotinic α4β2 subtype receptor partial agonist varenicline (VAR), which is used for smoking cessation, was investigated in Britton-Robinson buffers (pH 2.0-12.0) by cyclic, differential pulse and square wave voltammetry at a hanging mercury drop electrode (HMDE). The influence of pH, scan rate, concentration, accumulation potential and time on the peak current and potential suggested that the redox process was adsorption controlled in alkaline media. In addition, the experimental value of the surface coverage, G = 1.03×10-10 mol cm-2, was used to determine the conditions when VAR was fully adsorbed at the electrode surface. Bearing in mind the potential high toxicity of VAR due to the presence of a quinoxaline structure, its interaction with double stranded-DNA (ds-DNA) was postulated and studied when both compounds were in the adsorbed state at a modified HMDE. Using the adsorptive transfer technique, changes in potential and decreases in the normalized peak currents were observed. The estimated value of the ratio of surface-binding constants indicated that the reduced form of VAR interacted with ds-DNA more strongly than the oxidized form. Subtle DNA damage under conditions of direct DNA-VAR interaction at room temperature was observed. The proposed type of interaction was intercalation. This study employed a simple electroanalytical methodology and showed the potential of a DNA/ /HMDE biosensor for investigation of genotoxic effects.
AB  - Elektrohemijsko ponašanje vareniklina, novog parcijalnog agoniste α4β2 nikotinskog receptora, koji se koristi za odvikavanje od pušenja, ispitano je cikličnom, diferencijalno pulsnom i voltametrijom pravougaonih talasa u Briton-Robinsonovom puferu (pH 2,0-12,0). Na osnovu uticaja pH, brzine promene potencijala, koncentracije, potencijala i vremena akumulacije na visinu i položaj pika, zaključeno je da je proces redukcije u alkalnoj sredini kontrolisan adsorpcijom vareniklina. Korišćenjem eksperimentalno dobijene vrednosti površinske zaposednutosti, G = 1,03×10-10 mol cm-2, određeni su uslovi pod kojima je vareniklin potpuno adsorbovan na površini elektrode. Imajući u vidu moguću visoku toksičnost vareniklina, s obzirom na prisustvo hinoksalinskog prstena u strukturi, pretpostavljeno je da vareniklin interaguje sa DNK kada su oba molekula adsorbovana na modifikovanoj živinoj elektrodi. Ova interakcija je ispitana korišćenjem 'adsorptivne transfer tehnike' i primećene su promene potencijala i smanjenje normalizovanih struja voltametrijskih pikova. Na osnovu izračunate vrednosti odnosa konstanti vezivanja zaključeno je da se redukovani oblik vareniklina jače vezuje za DNK od oksidovanog. Pretpostavljeno je da direktna vareniklin-DNK interakcija na sobnoj temperaturi dovodi do izvesnog oštećenja DNK i da je tip interakcije - interkalacija. Ova jednostavna elektroanalitička metodologija mogla bi naći primenu u vidu potencijalnog biosenzora za ispitivanje genotoksičnih efekata.
PB  - Srpsko hemijsko društvo, Beograd
T2  - Journal of the Serbian Chemical Society
T1  - An electrochemical study of the adsorptive behaviour of varenicline and its interaction with DNA
T1  - Elektrohemijsko ispitivanje adsorpcije i interakcije vareniklina i DNK
VL  - 77
IS  - 10
SP  - 1409
EP  - 1422
DO  - 10.2298/JSC120420073R
ER  - 

@article{
author = "Radulović, Valentina and Aleksić, Mara and Kapetanović, Vera",
year = "2012",
abstract = "The electrochemical behaviour of a novel nicotinic α4β2 subtype receptor partial agonist varenicline (VAR), which is used for smoking cessation, was investigated in Britton-Robinson buffers (pH 2.0-12.0) by cyclic, differential pulse and square wave voltammetry at a hanging mercury drop electrode (HMDE). The influence of pH, scan rate, concentration, accumulation potential and time on the peak current and potential suggested that the redox process was adsorption controlled in alkaline media. In addition, the experimental value of the surface coverage, G = 1.03×10-10 mol cm-2, was used to determine the conditions when VAR was fully adsorbed at the electrode surface. Bearing in mind the potential high toxicity of VAR due to the presence of a quinoxaline structure, its interaction with double stranded-DNA (ds-DNA) was postulated and studied when both compounds were in the adsorbed state at a modified HMDE. Using the adsorptive transfer technique, changes in potential and decreases in the normalized peak currents were observed. The estimated value of the ratio of surface-binding constants indicated that the reduced form of VAR interacted with ds-DNA more strongly than the oxidized form. Subtle DNA damage under conditions of direct DNA-VAR interaction at room temperature was observed. The proposed type of interaction was intercalation. This study employed a simple electroanalytical methodology and showed the potential of a DNA/ /HMDE biosensor for investigation of genotoxic effects., Elektrohemijsko ponašanje vareniklina, novog parcijalnog agoniste α4β2 nikotinskog receptora, koji se koristi za odvikavanje od pušenja, ispitano je cikličnom, diferencijalno pulsnom i voltametrijom pravougaonih talasa u Briton-Robinsonovom puferu (pH 2,0-12,0). Na osnovu uticaja pH, brzine promene potencijala, koncentracije, potencijala i vremena akumulacije na visinu i položaj pika, zaključeno je da je proces redukcije u alkalnoj sredini kontrolisan adsorpcijom vareniklina. Korišćenjem eksperimentalno dobijene vrednosti površinske zaposednutosti, G = 1,03×10-10 mol cm-2, određeni su uslovi pod kojima je vareniklin potpuno adsorbovan na površini elektrode. Imajući u vidu moguću visoku toksičnost vareniklina, s obzirom na prisustvo hinoksalinskog prstena u strukturi, pretpostavljeno je da vareniklin interaguje sa DNK kada su oba molekula adsorbovana na modifikovanoj živinoj elektrodi. Ova interakcija je ispitana korišćenjem 'adsorptivne transfer tehnike' i primećene su promene potencijala i smanjenje normalizovanih struja voltametrijskih pikova. Na osnovu izračunate vrednosti odnosa konstanti vezivanja zaključeno je da se redukovani oblik vareniklina jače vezuje za DNK od oksidovanog. Pretpostavljeno je da direktna vareniklin-DNK interakcija na sobnoj temperaturi dovodi do izvesnog oštećenja DNK i da je tip interakcije - interkalacija. Ova jednostavna elektroanalitička metodologija mogla bi naći primenu u vidu potencijalnog biosenzora za ispitivanje genotoksičnih efekata.",
publisher = "Srpsko hemijsko društvo, Beograd",
journal = "Journal of the Serbian Chemical Society",
title = "An electrochemical study of the adsorptive behaviour of varenicline and its interaction with DNA, Elektrohemijsko ispitivanje adsorpcije i interakcije vareniklina i DNK",
volume = "77",
number = "10",
pages = "1409-1422",
doi = "10.2298/JSC120420073R"
}

Radulović, V., Aleksić, M.,& Kapetanović, V.. (2012). An electrochemical study of the adsorptive behaviour of varenicline and its interaction with DNA. in Journal of the Serbian Chemical Society
Srpsko hemijsko društvo, Beograd., 77(10), 1409-1422.
https://doi.org/10.2298/JSC120420073R

Radulović V, Aleksić M, Kapetanović V. An electrochemical study of the adsorptive behaviour of varenicline and its interaction with DNA. in Journal of the Serbian Chemical Society. 2012;77(10):1409-1422.
doi:10.2298/JSC120420073R .

Radulović, Valentina, Aleksić, Mara, Kapetanović, Vera, "An electrochemical study of the adsorptive behaviour of varenicline and its interaction with DNA" in Journal of the Serbian Chemical Society, 77, no. 10 (2012):1409-1422,
https://doi.org/10.2298/JSC120420073R . .

TY  - JOUR
AU  - Aleksić, Mara
AU  - Radulović, Valentina
AU  - Lijeskić, Nikola
AU  - Kapetanović, Vera
PY  - 2012
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/1739
AB  - The electrochemical study of varenicline (VAR) was done in a wide pH range (2-12), at boron doped diamond electrode (BDDE), glassy carbon electrode (GCE) and hanging mercury electrode (HMDE), using cyclic (CV), square wave (SW) and adsorptive stripping square wave (AdSSW) voltammetric techniques. Depending on the pH and the type of the working electrode the characteristic electrochemical behavior of varenicline was established. The mechanism of the reduction process was suggested. Based on the obtained results, the new electroanalytical method was developed for its determination in the buffer solutions and plasma samples. By applying a square wave voltammetry (SWV) on BDDE and GCE, at pH 3.5 and 4.0, the linear dependence in plasma samples was achieved within the concentration range from 2 10(-6) -1 x 10(-5) M and 4 x 10(-6) -1 x 10(-5) M, respectively. Limit of detection (LOD) and limit of quantification (LOQ) were obtained as 7.1 x 10(-7) M and 2.4 x 10(-6) M on BDDE, and 1.0 x 10(-6) M and 3.5 x 10(-6) M on GCE, respectively. The recovery and RSD values obtained for VAR in plasma suggested BDDE electrode to be preferable in comparison with GCE. The accuracy of the voltammetric method was confirmed by the determination of VAR in plasma spiked with Champix (R) tablets and the results were statistically compared with those obtained with Ultra Performance Liquid Chromatography (UPLC) method, as a reference one.
PB  - Bentham Science Publ Ltd, Sharjah
T2  - Current Analytical Chemistry
T1  - Electrochemical Response and Determination of Varenicline at Boron Doped Diamond, Glassy Carbon and Hanging Mercury Electrodes
VL  - 8
IS  - 1
SP  - 133
EP  - 142
UR  - https://hdl.handle.net/21.15107/rcub_farfar_1739
ER  - 

@article{
author = "Aleksić, Mara and Radulović, Valentina and Lijeskić, Nikola and Kapetanović, Vera",
year = "2012",
abstract = "The electrochemical study of varenicline (VAR) was done in a wide pH range (2-12), at boron doped diamond electrode (BDDE), glassy carbon electrode (GCE) and hanging mercury electrode (HMDE), using cyclic (CV), square wave (SW) and adsorptive stripping square wave (AdSSW) voltammetric techniques. Depending on the pH and the type of the working electrode the characteristic electrochemical behavior of varenicline was established. The mechanism of the reduction process was suggested. Based on the obtained results, the new electroanalytical method was developed for its determination in the buffer solutions and plasma samples. By applying a square wave voltammetry (SWV) on BDDE and GCE, at pH 3.5 and 4.0, the linear dependence in plasma samples was achieved within the concentration range from 2 10(-6) -1 x 10(-5) M and 4 x 10(-6) -1 x 10(-5) M, respectively. Limit of detection (LOD) and limit of quantification (LOQ) were obtained as 7.1 x 10(-7) M and 2.4 x 10(-6) M on BDDE, and 1.0 x 10(-6) M and 3.5 x 10(-6) M on GCE, respectively. The recovery and RSD values obtained for VAR in plasma suggested BDDE electrode to be preferable in comparison with GCE. The accuracy of the voltammetric method was confirmed by the determination of VAR in plasma spiked with Champix (R) tablets and the results were statistically compared with those obtained with Ultra Performance Liquid Chromatography (UPLC) method, as a reference one.",
publisher = "Bentham Science Publ Ltd, Sharjah",
journal = "Current Analytical Chemistry",
title = "Electrochemical Response and Determination of Varenicline at Boron Doped Diamond, Glassy Carbon and Hanging Mercury Electrodes",
volume = "8",
number = "1",
pages = "133-142",
url = "https://hdl.handle.net/21.15107/rcub_farfar_1739"
}

Aleksić, M., Radulović, V., Lijeskić, N.,& Kapetanović, V.. (2012). Electrochemical Response and Determination of Varenicline at Boron Doped Diamond, Glassy Carbon and Hanging Mercury Electrodes. in Current Analytical Chemistry
Bentham Science Publ Ltd, Sharjah., 8(1), 133-142.
https://hdl.handle.net/21.15107/rcub_farfar_1739

Aleksić M, Radulović V, Lijeskić N, Kapetanović V. Electrochemical Response and Determination of Varenicline at Boron Doped Diamond, Glassy Carbon and Hanging Mercury Electrodes. in Current Analytical Chemistry. 2012;8(1):133-142.
https://hdl.handle.net/21.15107/rcub_farfar_1739 .

Aleksić, Mara, Radulović, Valentina, Lijeskić, Nikola, Kapetanović, Vera, "Electrochemical Response and Determination of Varenicline at Boron Doped Diamond, Glassy Carbon and Hanging Mercury Electrodes" in Current Analytical Chemistry, 8, no. 1 (2012):133-142,
https://hdl.handle.net/21.15107/rcub_farfar_1739 .

TY  - JOUR
AU  - Aleksić, Mara
AU  - Radulović, Valentina
AU  - Kapetanović, Vera
AU  - Savić, Vladimir
PY  - 2010
UR  - https://farfar.pharmacy.bg.ac.rs/handle/123456789/1359
AB  - The electrochemical behaviour of desloratadine (DLOR) and its derivative 3-hydroxydesloratadine (3OH-DLOR) was investigated by direct current (DCP) polarography, cyclic (CV), differential pulse (DPV) and square-wave (SWV) voltammetry in Britton-Robinson (BR) buffer solutions (pH 4-11). Both compounds are reduced at mercury electrode in irreversible two electron reduction of the C=N bond of the pyridine ring in their molecules. The difference in their electrochemical behaviour was investigated, and the most pronounced distinction is observed at pH > 9, as a consequence of the deprotonation of the phenolic moiety in 3OH-DLOR molecule, yielding significant change in their reduction potentials (E (p DLOR) = -1.48 V, and E(p 3OH-DLOR) = -1.6 V). The observed results correlate with calculated LUMO energy levels and Hammet substituent constants (sigma). Based on the difference in the reduction potential for DLOR and 3OH-DLOR, conditions for simultaneous determination these two molecules in alkaline medium were established. The best selectivity was achieved using SWV method at pH 10. The linearity of the calibration graphs were achieved in the concentration range from 1.5 x 10(-6) M-1 x 10(-5) M for DLOR and 7.5 x 10(-6) M(-5) x 10(-5) M for 3OH-DLOR with detection limits of 2.29 x 10(-7) M and 2.08 x 10(-6) M, and determination limits of 7.64 x 10(-7) M and 6.94 x 10(-6) M, for DLOR and 3OH-DLOR, respectively. The method was checked in human plasma sample. Good response was obtained with LOD and LOQ values of 4.63 x 10(-7) M and 1.54 x 10(-6) M, for DLOR and 2.39 x 10(-6) M and 7.97 x 10(-6) M, 3OH-DLOR, respectively.
PB  - Slovensko Kemijsko Drustvo, Ljubljana
T2  - Acta Chimica Slovenica
T1  - The Possibility of Simultaneous Voltammetric Determination of Desloratadine and 3-Hydroxydesloratadine
VL  - 57
IS  - 3
SP  - 686
EP  - 692
UR  - https://hdl.handle.net/21.15107/rcub_farfar_1359
ER  - 

@article{
author = "Aleksić, Mara and Radulović, Valentina and Kapetanović, Vera and Savić, Vladimir",
year = "2010",
abstract = "The electrochemical behaviour of desloratadine (DLOR) and its derivative 3-hydroxydesloratadine (3OH-DLOR) was investigated by direct current (DCP) polarography, cyclic (CV), differential pulse (DPV) and square-wave (SWV) voltammetry in Britton-Robinson (BR) buffer solutions (pH 4-11). Both compounds are reduced at mercury electrode in irreversible two electron reduction of the C=N bond of the pyridine ring in their molecules. The difference in their electrochemical behaviour was investigated, and the most pronounced distinction is observed at pH > 9, as a consequence of the deprotonation of the phenolic moiety in 3OH-DLOR molecule, yielding significant change in their reduction potentials (E (p DLOR) = -1.48 V, and E(p 3OH-DLOR) = -1.6 V). The observed results correlate with calculated LUMO energy levels and Hammet substituent constants (sigma). Based on the difference in the reduction potential for DLOR and 3OH-DLOR, conditions for simultaneous determination these two molecules in alkaline medium were established. The best selectivity was achieved using SWV method at pH 10. The linearity of the calibration graphs were achieved in the concentration range from 1.5 x 10(-6) M-1 x 10(-5) M for DLOR and 7.5 x 10(-6) M(-5) x 10(-5) M for 3OH-DLOR with detection limits of 2.29 x 10(-7) M and 2.08 x 10(-6) M, and determination limits of 7.64 x 10(-7) M and 6.94 x 10(-6) M, for DLOR and 3OH-DLOR, respectively. The method was checked in human plasma sample. Good response was obtained with LOD and LOQ values of 4.63 x 10(-7) M and 1.54 x 10(-6) M, for DLOR and 2.39 x 10(-6) M and 7.97 x 10(-6) M, 3OH-DLOR, respectively.",
publisher = "Slovensko Kemijsko Drustvo, Ljubljana",
journal = "Acta Chimica Slovenica",
title = "The Possibility of Simultaneous Voltammetric Determination of Desloratadine and 3-Hydroxydesloratadine",
volume = "57",
number = "3",
pages = "686-692",
url = "https://hdl.handle.net/21.15107/rcub_farfar_1359"
}

Aleksić, M., Radulović, V., Kapetanović, V.,& Savić, V.. (2010). The Possibility of Simultaneous Voltammetric Determination of Desloratadine and 3-Hydroxydesloratadine. in Acta Chimica Slovenica
Slovensko Kemijsko Drustvo, Ljubljana., 57(3), 686-692.
https://hdl.handle.net/21.15107/rcub_farfar_1359

Aleksić M, Radulović V, Kapetanović V, Savić V. The Possibility of Simultaneous Voltammetric Determination of Desloratadine and 3-Hydroxydesloratadine. in Acta Chimica Slovenica. 2010;57(3):686-692.
https://hdl.handle.net/21.15107/rcub_farfar_1359 .

Aleksić, Mara, Radulović, Valentina, Kapetanović, Vera, Savić, Vladimir, "The Possibility of Simultaneous Voltammetric Determination of Desloratadine and 3-Hydroxydesloratadine" in Acta Chimica Slovenica, 57, no. 3 (2010):686-692,
https://hdl.handle.net/21.15107/rcub_farfar_1359 .