HPLC method development for the simultaneous analysis of amlodipine and valsartan in combined dosage forms and in vitro dissolution studies

A simple, rapid and reproducible HPLC method was developed for the simultaneous determination of amlodipine and valsartan in their combined dosage forms, and for drug dissolution studies. A C 18 column (ODS 2, 10 mu m, 200 x 4.6 mm) and a mobile phase of phosphate buffer (pH 3.6, 0.01 mol L-1): acetonitrile: methanol (46: 44: 10 v/v/v) mixture were used for separation and quantification. Analyses were run at a flow-rate of 1 mL min(-1) and at ambient temperature. The injection volume was 20 mu L and the ultraviolet detector was set at 240 nm. Under these conditions, amlodipine and valsartan were eluted at 7.1 min and 3.4 min, respectively. Total run time was shorter than 9 min. The developed method was validated according to the literature and found to be linear within the range 0.1 -50 mu g mL(-1) for amlodipine, and 0.05 - 50 mu g mL(-1) for valsartan. The developed method was applied successfully for quality control assay of amlodipine and valsartan in their combination drug product and in vitro dissolution studies.