Development of Stability Indicating RP-HPLC Method for Simultaneous Estimation of Amlodipine and Olmesartan in Pure and Pharmaceutical Dosage Form

Abstract

A precise, accurate, economical and simple stability indicating RP-HPLC method was developed for the estimation of Amlodipine (AML) and Olmesartan (OLM) in bulk and pharmaceutical dosage form. Method was performed on a octadecyl silane column with dimensions 4.6 x 250 mm having particle size 5 micron. The mobile phase used in the method is TEA Buffer (pH 3.0) and acetonitrile in proportion of 25:75 respectively. The flow rate was maintained at 1.0 ml/ min and effluent was monitored at 258 nm. The drug was subjected to acid and alkali hydrolysis, oxidation, photolysis and heat as stress conditions. The method was validated for specificity, linearity, precision, accuracy, robustness and system suitability. The retention times were observed at 2.39 min and 3.33 min for AML and OLM respectively. The standard curve was found linear over a range of 05–35 μg/ml for AML and OLM. Similarly an average correlation coefficient was also obtained at 0.999 for AML and OLM. The limit of quantitation (LOQ) of this method was 2μg/ml for Amlodipine and Olmesartan. The absolute recovery was 100% for Amlodipine and 100.3 for Olmesartan. Degradation products produced as a result of stress studies did not interfere with the detection of AML and OLM and the assay can thus be considered stability-indicating.