A stability-indicating RP-HPLC method has been established for analysis of telmisartan (TEL) and hydrochlorothiazide (HTZ) in the presence of degradation products formed under different stress conditions. The drug substances were subjected to stress by hydrolysis (1N NaOH, 1N HCl and neutral), oxidation (3% v/v H2O2), photochemical, thermal (100Ã?¡Ã?µÃ?â??C), and UV degradation (254 nm). Both the drugs were degraded under selected experimental conditions. Successful separation of the drugs from the degradation products was achieved on a hypersil gold C18 column with 40:60 (v/v) acetonitrile-aqueous 0.01M potassium dihydrogen o-phosphate buffer (pH 3 adjusted with 2% v/v o-phosphoric acid) as mobile phase. The method was linear over the concentration range of 6-36 μg mL-1 (r > 0.991), with limits of detection and quantitation (LOD and LOQ) of 0.495 and 1.50 μg mL-1, respectively, for TEL and 2-12 μg mL-1 (r > 0.991) with LOD and LOQ of 0.873 and 2.64 μg mL-1, respectively, for HTZ. The method was validated for specificity, selectivity, accuracy, and precision. This method was reproducible and selective. As the developed method could effectively separate the drugs from their degradation products, it can be used as stability-indicating.
