Development and validation of RP-HPLC method for simultaneous estimation of atrovastatin and olmesartan in pharmaceutical formulations

Combination therapy of Atorvastatin (AT) and Olmesartan (OLM) is used for the treatment of co existing essential hypertension and hyperlipidemia in adult persons. In the present study a simple, precise, rapid, efficient and reproducible reversed phase high performance liquid chromatography (RP-HPLC) method has been developed for the simultaneous estimation of AT and OLM present in its tablet dosage forms. Chromatographic separations were carried out isocratically at 30°C ± 0.5°C on a hypersil bds C18 (100,4.6 mm,5?) with a mobile phase composed of Sodium dihydrogen phosphate pH 4.5 with dilute phosphoric acid : Methanol: Acetonitrile in the ratio of 65:20:15 % v/v at a flow rate of 1.0 ml/min. Detection is carried out using a UV detector at 232 nm. The retention times for OLM and AT were 2.23 min and 3.46 min respectively. The linearity range for 20-100 ìg/ml AT and OLM were found to be 40-200 ìg/ml with correlation coefficient of 0.999 and 0.999 respectively. The % recovery of the proposed method was found in the range of 100.39 for AT and 98.53 for OLM. The relative standard deviations for three replicate measurements in three concentrations of standard solution were always less than 2%. The results of the study showed that the proposed RP-HPLC method is simple, rapid, precise and accurate, which may be useful for the routine estimation of AT and OM in bulk drug and in its pharmaceutical dosage form.