Stability indicating spectrophotometric methods for quantitative determination of carbamazepine and its degradation product, iminostilbene, in pure form and pharmaceutical formulations

摘要

A stressed study on the stability and degradation behavior under ICH forced degradation conditions of most widely used antiepileptic drug; carbamazepine (CMZ) is presented in thiswork. The research also includes studying spectrophotometric nature of CMZ and assaying itwithmostly used spectrophotometric techniques. Six simple and sensitive spectrophotometric methods are introduced as stability indicating methods for quantitative determination of CMZ and its degradation product, one of its reported potential impurities; iminostilbene (IMS). Dual wavelength is method I where two wavelengths (215 and 270 nm for CMZ and 258 and 307 nm for IMS) were chosen for each component while absorbance difference is zero for the second one. Method II is isoabsorptive point method where the absorbance of CMZ at A(225 nm) was measured in the range of 0.5-20 mu g mL(-1). Method III is second derivative method which allows simultaneous determination of CMZ at 247 nm and IMS at 273 nm without any interference. Method IV based on measuring the peak amplitude of first derivative of ratio spectra ((DD)-D-1) at 280.5 and 253 nm for determination of CMZ and IMS, respectively. Method V ismean centering of the ratio spectrawith good linearity for CMZ and IMS over 200-330 nm. Ratio differencemethod ismethod VIwhere good linearitywas achieved for determination of CMZ and IMS bymeasuring differences in the amplitude of ratio spectra at 285, 258 nm and 258, 285 nm, respectively. The proposed methods show successful application in CMZ's pharmaceutical formulations. (C) 2019 Elsevier B.V. All rights reserved.