Abstract

Rapid determination of amlodipine besylate and valsartan in pharmaceutical preparations by stability-indicating ultra performance liquid chromatography

Author(s): Yarram Ramakoti Reddy, Kakumani Kishore Kumar, M.R.P.Reddy, K.Mukkanti

A stability- indicating UPLC method was developed for the simultaneous quantitative determination of amlodipine besylate and valsartan in pharmaceutical dosage forms in the presence of degradation products. It involved a 50 mm x 4.6 mm, 1.8 µm C-18 column. The separation was achieved on simple isocratic method. A mixture of potassium dihydrogen phosphate buffer (pH 3.2, 0.01M)- acetonitrile (55:45, v/v) was used as the mobile phase. The flow rate was 0.7 ml/min and the detection wavelength was 237 nm. The retention times of amlodipine besylate and valsartan were 0.8 min and 1.3 min; respectively. The total runtime was 2 min within which both active compounds and degradation products were separated. Amlodipine besylate and valsartan were subjected to different ICH prescribed stress conditions. Degradation was found to occur in hydrolytic stress conditions and some extent in oxidative stress conditions, while drugs were stable to photolytic and thermal stress. The drugs were particularly labile under acidic stress conditions. The drugs were subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. The method developed was successfully applied to the simultaneous determination of amlodipine besylate and valsartan in pharmaceutical preparations. The developed RP-UPLC method was validated with respect to linearity, accuracy, precision, robustness and ruggedness.