An approach of forced degradation study was successfully applied for development and validation of stability indicating RRLC assay method for the simultaneous estimation and quantification of three anti-hypertensive drugs olmesartan medoxomil, hydrochlorothiazide and amlodipine besylate in marketed formulation in presence of its degradation products. The method showed separation of all three drugs from their associated degradation products. The separation was achieved on zorbax SB C18 column (50 x 4.6 mm id, 1.8 µm particle size) using mobile phase of triethylamine buffer solution (at pH 3): acetonitrile (gradient program). The flow rate was 1 ml/min, injection volume 3 µl and detection was done at 236 nm on photodiode array detector. Gradient program for RRLC method was used for proper separation of peaks. Comprehensive stress testing of all drugs was carried out as per ICH guideline Q1A (R2). There were no other coeluting, interfering peaks from excipients, impurities, or degradation products due to variable stress conditions and the method was specific for determination of all drugs in the presence of degradation products. The retention time for hydrochlorothiazide, amlodipine besylate and olmesartan medoxomil was 1.2 min, 1.8 min and 2.1 min respectively. The linearity of method was investigated in range of 5-40 µg/ml for olmesartan medoxomil, 3.125-25 µg/ml for hydrochlorothiazide and 1.25-10 µg/ml for amlodipine besylate respectively. Validation results showed satisfactory linearity, accuracy, precision, robustness and ruggedness. The detection wavelength of 236 nm was chosen in order to achieve a good sensitivity for quantitative determination of all drugs in solid dosage form. Method can be successfully employed for simultaneous estimation of all drugs in commercial products.
Loading....