Development and Validation of a Stability-indicating RP-HPLC Method for the Simultaneous Determination of Telmisartan and its Related Substances in Telmisartan Bulk Drug Substance

A simple gradient liquid chromatographic method with UV detection at 230 nm, which is suitable for the analysis Telmisartan in different bulk drug samples, is presented in this study. Telmisartan is separated from its intermediates and a degradation product as well as from unknown impurities on Kromasil C18 column at 40 & DEG;C using a mobile phase that consisted of 0.1 % ammonium hydroxide solution adjusted pH 3.0 with TFA as eluent-I and acetonitrile: methanol (80:20) as eluent-II at 1.0 mL/min. Forced degradation studies reveal that telmisartan undergoes degradation under acidic as well as oxidative stress conditions. The resulting degradation products did not interfere with the detection of telmisartan and its potential impurities which demonstrates the stability-indicating capability of this method. Method validation studies with respect to specificity, linearity, precision, accuracy, sensitivity, and robustness were carried out in accordance with the International Conference on Harmonisation (ICH) guidelines. The method would be possibly useful for purity assessment of telmisartan in bulk drug as well as for its assay in dosage formulations.