NEW VALIDATED STABILITY INDICATING RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF AMLODIPINE BESYLATE AND VALSARTAN IN PHARMACEUTICAL FORMULATION

A simple, specific, accurate and precise and stability indicating RP-HPLC method was developed and validated for the simultaneous estimation of Amlodipine Besylate and Valsartan in pharmaceutical formulation. The method was developed using Enable C 18G column (250 x 4.6 mm, 0.5 mu m) with a mobile phase consisting of sodium acetate buffer (pH 5.0) and methanol (35: 65% v/v) with a flow rate of 1 mL/min. The UV detection was carried out at 234 nm. The retention time for Amlodipine Besylate and Valsartan were found to be 3.146 and 6.543 min respectively. The proposed method was validated for linearity, range, accuracy, precision, robustness, LOD and LOQ. Linearity was observed over a concentration range 0.5-250 mu g/ml for amlodipine besylate (r(2) = 0.9996) and 1-90 mu g/ml for Valsartan (r(2) = 0.9984). The % RSD for Intraday and Interday precision was found to be 0.37 and 0.57 for Amlodipine Besylate and 0.48 and 0.75 for Valsartan. The LOD and LOQ were found to be 0.01 mu g/ml, and 0.04 mu g/ml for Amlodipine Besylate and LOD and LOQ were found to be 0.04 and 0.14 mu g/ml for Valsartan respectively. Amlodipine Besylate and Valsartan were subjected to stress conditions of degradation including acidic, alkaline, oxidative, thermal and photolysis.