DEVELOPMENT AND VALIDATION OF RP–HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF ATORVASTATIN AND METOPROLOL SUCCINATE IN COMBINED PHARMACEUTICAL DOSAGE FORMS

A simple and accurate method was developed using Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) to measure Atorvastatin calcium (ATS) and Metoprolol Succinate (MET) together for pure drug and in tablets. The separation was done using a Shimadzu Shim-pack C8 column with dimensions 4.6 mm by 250 mm and a particle size of 5 micrometers. The mobile phase consisted of HPLC-grade acetonitrile, methanol, and water in a ratio of 50:30:20 by v/v, and the pH was adjusted to 3 using 1% o-phosphoric acid. The flow rate was set at 1.0 ml per minute. Both drugs were detected at a wavelength of 220 nm, with the retention time of ATS at 4.402 minutes and MET at 3.367 minutes. The method showed good linearity across the concentration ranges of 10 to 200 μg/ml for ATS and 25 to 500 μg/ml for MET, with correlation coefficient of ATS was 0.9996 and MET was 0.9999. The limits of detection and quantification were 1.026 and 3.110 μg/ml for ATS, and 5.053 and 15.31 μg/ml for MET. The method was validated for accuracy, precision, and robustness following ICH Q2 (R2) guidelines, proving it is suitable for regular use in checking the quality of combined medicine tablets.