Stability-Indicating Method for Simultaneous Estimation of Olmesartan Medoxomile, Amlodipine Besylate and Hydrochlorothiazide by RP-HPLC in Tablet Dosage Form

A simple, specific, accurate and precise stability-indicating reversed-phase high-performance liquid chromatographic method was developed for simultaneous estimation of olmesartan medoxomile (DIME), amlodipine besylate (AMLO) and hydrochlorothiazide (HCTZ) in tablet dosage form. The method was developed using an RP C18 base deactivated silica column (250 x 4.6 mm, 5 mu m) with a mobile phase consisting of triethylamine (pH 3.0) adjusted with orthophosphoric acid (A) and acetonitrile (B), with a timed gradient program of T/%B: 0/30, 7/70, 8/30, 10/30 with a flow rate of 1.4 mL/min. Ultraviolet detection was used at 236 nm. The retention times for DIME, AMID and HCTZ were found to be 6.72, 4.28 and 2.30, respectively. The proposed method was validated for precision, accuracy, linearity, range, robustness, ruggedness and force degradation study. The calibration curves of OLME, AMID and HCTZ were linear over the range of 50-150, 12.5-37.5 and 31-93 mu g/ml, respectively. The method was found to be sensitive. The limits of detection of OLME, AMID and HCTZ were determined 0.19, 0.16 and 0.22 mu g/mL and limits of quantification of OLME, AMID and HCTZ were determined 0.57, 0.49 and 0.66, respectively. Forced degradation study was performed according to International Conference on Harmonization guidelines.