A New RP-HPLC Method Development and Validation for the Simultaneous Estimation of Amlodipine and Valsartan in Tablet Dosage Forms

A simple, accurate, rapid and precise isocratic reversed-phase high-performance liquid chromatographic method has been developed and validated for simultaneous determination of Amlodipine and Valsartan in tablets. The chromatographic separation was carried out on an cosmosil packed column 5c-18 ms II (250×4.6 i.d) with a mixture of acetonitrile: methanol: phosphate buffer pH 3 adjusted with orthophosphoric acid (20:50:30, v/v) as mobile phase; at a flow rate of 1.0 ml/min. UV detection was performed at 239 nm. The retention times were 4.915 and 8.056 min. for Amlodipine and Valsartan respectively. Calibration plots were linear (r2>0.998) over the concentration range 10–60 μg/ml for Amlodipine and 10–60 μg/ml Valsartan. The method was validated for accuracy, precision, specificity, linearity, and sensitivity. The proposed method was successfully used for quantitative analysis of tablets. No interference from any component of pharmaceutical dosage form was observed. Validation studies revealed that method is specific, rapid, reliable, and reproducible. The high recovery and low relative standard deviation confirm the suitability of the method for routine determination of Amlodipine and Valsartan in bulk drug and tablet dosage form.