The main aim of the current research work was to develop simple, rapid, robust, accurate and more precise stability indicating RP-HPLC method for simultaneous estimation of candesartan cilexetil and hydrochlorothiazde in active pharmaceutical ingredient and in tablet dosage form. The RP-HPLC analysis was carried out on an enable C18 (Kromasil, ODS, 5 μ, 250 X 4.5 mm) column with a mobile phase of methanol-acetonitrile-disodium hydrogen phosphate (0.01 M; pH adjusted to 2.5 with orthophosphoric acid) in the ratio of 20:30:50 (v/v/v). UV detection was performed at 240 nm. The method was found to be linear over a concentration range of 10-500 μg/ml and 0.4-25 μg/ml for candesartan cilexetil and hydrochlorothiazide respectively. The limit of detection was found to be as 2.5μg/ml and 100ng/ml for candesartan cilexetil and hydrochlorothiazide respectively. The limit of quantitation was found to be as 10μg/ml and 100ng/ml for candesartan cilexetil and hydrochlorothiazide. Recovery was found to be in the range 99-100% and precision less than 1%. Developed method was successfully applied for routine analysis of pure drug and pharmaceutical formulations. Forced degradation studies were performed for candesartan cilexetil and hydrochlorothiazide. The drugs were degraded in acidic, basic and oxidative conditions. The peaks of degraded products were well resolved from the actual drug. The developed method was simple, rapid, accurate, precise and stability indicating for the simultaneous estimation of candesartan cilexetil and hydrochlorothiazide in active pharmaceutical ingredient and in tablet dosage form.
