Development and Validation of RP-HPLC Method for Quantitative Estimation of Atorvastatin Calcium and Metoprolol Succinate in Combined Dose Capsule Formulation

A simple, specific, accurate and precise reverse phase high performance liquid chromatographic method have been developed and validated for simultaneous determination of Atorvastatin calcium and Metoprolol succinate in capsules. Chromatography was carried out by gradient technique on a reversed-phase C-18 column (4.6 mm x 250 mm, 5/m) using acetonitrile -phosphate buffer (pH 3.5) -methanol (50:40:10, v/v/v) as a mobile phase at a flow rate of 1.0 ml/min and UV detection at 276 nm. The linearity of the calibration curves for each analyte in the desired concentration range was good (r² > 0.99). The method was accurate and precise with recoveries in the range of 99.84% and 100.62% for both the drugs and relative standard deviation (R.S.D.) < 2. The proposed method is highly sensitive, accurate and precise and hence was successfully applied for the reliable quantification of API content in the commercial formulation containing these drugs in combination. The different analytical performance parameters such as linearity, accuracy, precision, robustness, limit of detection (LOD) and limit of quantification (LOQ) were determined according to International Conference on Harmonization ICH Q2B guidelines.