TY  - JOUR
AU  - Milovanović, GA
AU  - Čakar, Mira M.
AU  - Vučić, Nevenka B.
AU  - Jokanović, Milan
PY  - 2000
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/2397
AB  - In this work it was established that, in the presence of ammonium carbonate, traces of manganese(II) catalyse the oxidation of Nile Blue A by hydrogen peroxide, which enables its: kinetic determination in the concentration range from 6.6 to 65.9 ng cm(-3), the detection limit being 8.0 x 10(-2) ng cm(-3). Antiviral/antitumour substances modify the catalytic activity of manganese (TT): 1-beta -D-ribofuranosyl-1,2,4-triazole-3-carboxamide, ribavirin, increases the catalytic effect of manganese(II), while 2-beta -D-ribofuranosyl-thiazole-4-carboxamide, tiazofurin, acts as an inhibitor. On the basis of these effects, a kinetic method for determining ribavirin concentrations from 0.5 x 10(-1) to 4.0 x 10(-1) mug cm(-3) and tiazofurin concentrations from 0.3 to 2.6 mug cm(-3) is proposed. The kinetics of the indicator reaction were studied ill the presence of the substances examined, the kinetic equations established, and the constants of the corresponding reaction rates calculated. The effect of temperature on these reactions was also investigated. The method was applied to the determination of manganese(II) in mineral water and ribavirin in pharmaceutical preparations.
T2  - Microchimica Acta
T1  - Selective indicator reaction for kinetic determination of traces of manganese(II), ribavirin and tiazofurin
VL  - 135
IS  - 3-4
SP  - 173
EP  - 178
DO  - 10.1007/s006040070007
ER  - 

@article{
author = "Milovanović, GA and Čakar, Mira M. and Vučić, Nevenka B. and Jokanović, Milan",
year = "2000",
abstract = "In this work it was established that, in the presence of ammonium carbonate, traces of manganese(II) catalyse the oxidation of Nile Blue A by hydrogen peroxide, which enables its: kinetic determination in the concentration range from 6.6 to 65.9 ng cm(-3), the detection limit being 8.0 x 10(-2) ng cm(-3). Antiviral/antitumour substances modify the catalytic activity of manganese (TT): 1-beta -D-ribofuranosyl-1,2,4-triazole-3-carboxamide, ribavirin, increases the catalytic effect of manganese(II), while 2-beta -D-ribofuranosyl-thiazole-4-carboxamide, tiazofurin, acts as an inhibitor. On the basis of these effects, a kinetic method for determining ribavirin concentrations from 0.5 x 10(-1) to 4.0 x 10(-1) mug cm(-3) and tiazofurin concentrations from 0.3 to 2.6 mug cm(-3) is proposed. The kinetics of the indicator reaction were studied ill the presence of the substances examined, the kinetic equations established, and the constants of the corresponding reaction rates calculated. The effect of temperature on these reactions was also investigated. The method was applied to the determination of manganese(II) in mineral water and ribavirin in pharmaceutical preparations.",
journal = "Microchimica Acta",
title = "Selective indicator reaction for kinetic determination of traces of manganese(II), ribavirin and tiazofurin",
volume = "135",
number = "3-4",
pages = "173-178",
doi = "10.1007/s006040070007"
}

Milovanović, G., Čakar, M. M., Vučić, N. B.,& Jokanović, M.. (2000). Selective indicator reaction for kinetic determination of traces of manganese(II), ribavirin and tiazofurin. in Microchimica Acta, 135(3-4), 173-178.
https://doi.org/10.1007/s006040070007

Milovanović G, Čakar MM, Vučić NB, Jokanović M. Selective indicator reaction for kinetic determination of traces of manganese(II), ribavirin and tiazofurin. in Microchimica Acta. 2000;135(3-4):173-178.
doi:10.1007/s006040070007 .

Milovanović, GA, Čakar, Mira M., Vučić, Nevenka B., Jokanović, Milan, "Selective indicator reaction for kinetic determination of traces of manganese(II), ribavirin and tiazofurin" in Microchimica Acta, 135, no. 3-4 (2000):173-178,
https://doi.org/10.1007/s006040070007 . .

TY  - JOUR
AU  - Čakar, Mira M.
AU  - Vasić, Vesna M.
AU  - Petkovska, Ljubica T.
AU  - Stojić, Dragica Lj.
AU  - Avramov-Ivic, M
AU  - Milovanović, GA
PY  - 1999
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/2258
AB  - Newly synthesized oximes, mono and bis imidazole derivatives, which promise to be more effective acetylcholinesterase reactivators than standard antidotes used, were investigated by spectrophotometric and electrochemical methods. The electrochemical investigations confirmed the existence of overlapping equilibria, obtained by spectrophotometric methods. Dissociation constants of those oximes were also obtained by numerical treatment of overlapping equilibria, using the Lavendberg-Marquardt least square method, and when compared with the same for some similar compounds, were found to be very effective acetylcholinesterase reactivators. The distribution of ionic forms of the investigated oximes, as a dependence of pH values, was calculated from the obtained values of dissociation constants. The results indicated that many oxime anions will be available at physiological pH 7.4 and a relative increased ability to reactivate inhibited acetylcholinesterase could be expected. (C) 1999 Elsevier Science B.V. All rights reserved.
T2  - Journal of Pharmaceutical and Biomedical Analysis
T1  - Spectrophotometric and electrochemical study of protolytic equilibria of some oximes-acetylcholinesterase reactivators
VL  - 20
IS  - 4
SP  - 655
EP  - 662
DO  - 10.1016/S0731-7085(99)00056-4
ER  - 

@article{
author = "Čakar, Mira M. and Vasić, Vesna M. and Petkovska, Ljubica T. and Stojić, Dragica Lj. and Avramov-Ivic, M and Milovanović, GA",
year = "1999",
abstract = "Newly synthesized oximes, mono and bis imidazole derivatives, which promise to be more effective acetylcholinesterase reactivators than standard antidotes used, were investigated by spectrophotometric and electrochemical methods. The electrochemical investigations confirmed the existence of overlapping equilibria, obtained by spectrophotometric methods. Dissociation constants of those oximes were also obtained by numerical treatment of overlapping equilibria, using the Lavendberg-Marquardt least square method, and when compared with the same for some similar compounds, were found to be very effective acetylcholinesterase reactivators. The distribution of ionic forms of the investigated oximes, as a dependence of pH values, was calculated from the obtained values of dissociation constants. The results indicated that many oxime anions will be available at physiological pH 7.4 and a relative increased ability to reactivate inhibited acetylcholinesterase could be expected. (C) 1999 Elsevier Science B.V. All rights reserved.",
journal = "Journal of Pharmaceutical and Biomedical Analysis",
title = "Spectrophotometric and electrochemical study of protolytic equilibria of some oximes-acetylcholinesterase reactivators",
volume = "20",
number = "4",
pages = "655-662",
doi = "10.1016/S0731-7085(99)00056-4"
}

Čakar, M. M., Vasić, V. M., Petkovska, L. T., Stojić, D. Lj., Avramov-Ivic, M.,& Milovanović, G.. (1999). Spectrophotometric and electrochemical study of protolytic equilibria of some oximes-acetylcholinesterase reactivators. in Journal of Pharmaceutical and Biomedical Analysis, 20(4), 655-662.
https://doi.org/10.1016/S0731-7085(99)00056-4

Čakar MM, Vasić VM, Petkovska LT, Stojić DL, Avramov-Ivic M, Milovanović G. Spectrophotometric and electrochemical study of protolytic equilibria of some oximes-acetylcholinesterase reactivators. in Journal of Pharmaceutical and Biomedical Analysis. 1999;20(4):655-662.
doi:10.1016/S0731-7085(99)00056-4 .

Čakar, Mira M., Vasić, Vesna M., Petkovska, Ljubica T., Stojić, Dragica Lj., Avramov-Ivic, M, Milovanović, GA, "Spectrophotometric and electrochemical study of protolytic equilibria of some oximes-acetylcholinesterase reactivators" in Journal of Pharmaceutical and Biomedical Analysis, 20, no. 4 (1999):655-662,
https://doi.org/10.1016/S0731-7085(99)00056-4 . .