Original Articles
Mohammad Yunoos and D. Gowri S
Abstract
A simple and precise stability indicating RP-HPLC method was developed and validated for the simultaneous determination of Olmesartan Medoxomil and Chlorthalidonein pure drug and pharmaceutical dosage forms. Chromatography was carried out on STD HypersilC18(150x4.6mm, 5μ particle size) analytical column using a mobile phase ofPhosphate buffer(KH2PO4) adjusted topH 5.0 with dilute orthophosphoric acidand methanol in the ratio of 40: 60 % v/v at a flow rate of 1.2 ml/min. The analyte was monitored using PDA detector at 240 nm. The retention time was found to be 2.240min and 3.042min for Olmesartan Medoxomil and Chlorthalidone respectively. Linearity was observed in the concentration range of 60-180 μg/mland 18.75-56.25 μg/mlfor both Olmesartan Medoxomil and Chlorthalidonewith correlation coefficient of 0.999 respectively. The mean % recoveries obtained for Olmesartan Medoxomil and Chlorthalidone were found to be 100.02% and 99.97% respectively.Stress testing which covered acid hydrolysis, base hydrolysis, peroxide, photolytic and thermal degradation was performed to prove the specificity of the proposed method and degradation was achieved. The developed method has been statistically validated according to ICH guide lines and found to be simple, precise and accurate with the prescribed values. Thus the proposed RP-HPLC method was successfully applied for the stability indicating simultaneous estimation of Olmesartan Medoxomil and Chlorthalidonein routine quality control analysis in bulk and marketed formulations.