Tipre D N, Vavia P R
Department of Chemical Technology, University of Mumbai, Matunga, India.
J Pharm Biomed Anal. 2001 Feb;24(4):705-14. doi: 10.1016/s0731-7085(00)00489-1.
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.
本研究的目的是开发经过验证的用于测定尼群地平的稳定性指示高效液相色谱法（A）、高效薄层色谱法（B）和分光光度法（C）。通过将药物溶液暴露于阳光、酸性和碱性介质中进行强制降解，证明了这些分析方法的稳定性指示能力。色谱图和紫外光谱显示尼群地平与降解产物得到了很好的分离。发现在100℃下，药物在酸性（0.1 N盐酸）介质中的降解速度比在碱性（0.1 N氢氧化钠）介质中更快。此外，还研究了光降解，特别强调了甲醇（1）、氯仿（2）、二氯甲烷（3）、丙酮（4）和乙酸乙酯（5）等溶剂对光降解速率的影响。在所有情况下，标题化合物的降解均遵循一级动力学。使用感兴趣的线性范围内的单点标准化，通过上述稳定性指示方法对药物进行测定。对这些方法的性能精密度和准确度进行了比较。发现在所有情况下，主要的降解途径是氧化，并且通过相关的紫外、红外和1H核磁共振光谱法确认降解产物为脱氢尼群地平。
