Oxidative degradation study of nitrendipine using stability indicating, HPLC, HPTLC and spectrophotometric method

The objective of this study is to develop validated stability indicating HPLC (A), HPTLC (B) and spectrophotometric (C) method for the estimation of nitrendipine. The stability indicating capability of the assays is proved using forced degradation, by exposing drug solution to sunlight, acidic and alkaline medium. The chromatogram and UV spectrum showed nitrendipine well resolved from the degradation product. Degradation of drug is found faster in acidic (0.1 N hydrochloric acid) medium as compared to alkaline (0.1 N sodium hydroxide) medium at 100 degrees C. Also, photodegradation is studied, with special emphasis on the effect of solvents like methanol (1), chloroform (2), dichloromethane (3), acetone (4) and ethyl acetate (5), on the rate of photodegradation. The degradation of title compound followed first order kinetics in all cases. Estimation of the drug is carried out by the stability indicating methods mentioned, using one point standardization within the linearity range of interest. The methods are compared in respect of performance precision and accuracy. Major route of degradation in all cases is found to be oxidation and degradation product is confirmed as dehydronitrendipine by the use of relevant UV, IR and 1H NMR spectrometry.