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

Abstract

A simple reverse phase HPLC method was developed for the simultaneous estimation of Amlodipine and Olmesartan in bulk and tablet form. Chromatography was performed by isocratic reverse phase separation on a stainless steel column 4.6 x 150mm, symmetry column packed with octa decyl silane bonded to porous silica (C18) with particle size 5 micron with mobile phase containing TEA Buffer of pH 3.0 and Acetonitrile in proportion of 25:75 respectively. The flow rate was 1.0 ml/ min and effluent was monitored at 258 nm. The retention times were 2.39 min and 3.33 min respectively. The standard curve was linear over a working range of 05–35 µg/ml for both Amlodipine and Olmesartan and gave an average correlation coefficient of 0.999, and 0.999 for Amlodipine and Olmesartan respectively. 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 Amlodipine and Olmesartan and the assay can thus be considered stability-indicating.