Forced Degradation Studies of Olmesartan medoxomil and Chlorthalidone: Development and Validation of Stability-Indicating RP‑HPLC method

A reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of olmesartan medoxomil (OLME) and chlorthalidone (CHLOR) in tablet dosage form. The analysis was performed on Inertsil ODS C18 (250 x 4.6 mm, 5 μ) using KH2PO4 phosphate buffer (pH) and acetonitrile as mobile phase in the proportion of 60: 40 v/v at flow rate of 1.0 mL/min. Detection of drugs was carried out in isocratic mode using UV detector at 275 nm. The retention time of OLME and CHLOR was 13.9 ± 0.1 min. and 4.4 ± 0.5 min., respectively and the total run time was 20 min. The method was validated according to the requirements of the United States Pharmacopeia. The percentage recoveries was found to be in the range of 98.9 - 100.7%. The method was successfully applied to the assay of OLME and CHLOR in tablet dosage form.