Abstract

SRIVASTAVA, Abhishek; SHARMA, Vivek; KUMAR SINGH, Vinay  and  SRIVASTAVA, Krishna. A Simple and Sensitive Inhibitory Kinetic Method for the Carbocisteine Determination. J. Mex. Chem. Soc [online]. 2022, vol.66, n.1, pp.57-69.  Epub Dec 05, 2022. ISSN 1870-249X.  https://doi.org/10.29356/jmcs.v66i1.1654.

A fast, reproducible, and sensitive method is proposed for the kinetic determination of carbocisteine (CCys). The method depends on the inhibitory property of carbocisteine, which reduces the Hg2+ catalyzed substitution rate of cyanide from [Ru(CN)6]4- with N-R-salt (1-Nitroso-2-naphthol-3,6-disulfonic acid disodium salt) via forming a stable complex with Hg2+. Spectrophotometric measurements were carried out by recording the absorbance at 525 nm (λmax of [Ru(CN)5 Nitroso-R-Salt]3- complex) at a fixed time of 10 and 15 min under the optimized reaction conditions with [N-R-salt] = 4.5 × 10-4 M, I = 0.05 M (KNO3), Temp = 45.0 ± 0.2 o C, pH = 7.0 ± 0.03, [Hg2+] = 8.0 × 10-5 M and [Ru(CN)6 4-] = 4.25 × 10-5 M. With the proposed method, CCys can be determined quantitatively down to 3.0 × 10-6 M. This methodology can be effectively used for the rapid quantitative estimation of CCys in the pharmaceutical samples with good accuracy and reproducibility. The addition of common excipients in pharmaceuticals even up to 1000 times with [CCys] does not interfere significantly in the estimation of CCys.

Keywords : Inhibitory effect; ligand substitution reaction; catalyst inhibitor complex; cxcipients; pharmaceutical preparations; hexacyanoruthenate(II).

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