A stability indicating RP-HPLC method development and validation for the estimation of combined tablet formulation of Amlodipine & Candesartan

A stability indicating High Performance Liquid Chromatographic (HPLC) method was developed and validated for the estimation of combined tablet formulation of Amlodipine & Candesartan. Chromatographic separation was optimized by Binary Gradient System HPLC on a Grace C18 (250mm x 4.6ID, Particle size: 5 micron) utilizing a mobile phase consisting a methanol: phosphate buffer (pH-3, adjusted with 0.1% OPA) 80:20 % v/v at a flow rate of 0.8ml/min with UV-3000-M at 244nm. The retention time of Amlodipine & Candesartan was 4.2min and 6.3 min respectively. Good linearity was obtained over the range of 5 μg/ml to 25 μg/ml & 8 μg/ml to 40 μg/ml for Amlodipine & Candesartan. Correlation coefficient was found to be 0.999 for both derivatives. The % RSD of precision Amlodipine & Candesartan was found to be 0.54 and 0.60 respectively. The % mean recovery was found to 98.93-99.00 % for Amlodipine and 99.75-99.87 %for Candesartan. The results obtained for accuracy, precision, LOD, LOQ and Ruggedness were within the limits. Thus the validated economical method was applied for forced degradation study of Amlodipine & Candesartan tablets.