STABILITY INDICATING RP-HPLC METHOD DEVELOPMENT AND VALIDATION FOR THE SIMULTANEOUS ESTIMATION OF DARUNAVIR, COBICISTAT, EMTRICITABINE AND TENOFOVIR ALAFENAMIDE IN BULK AND PHARMACEUTICAL FORMULATION

A simple, accurate & precise method was developed for the simultaneous estimation of Darunavir (DAR), Cobicistat (COB), Emtricitabine (EMT), and Tenofovir alafenamide (TEN) in their bulk and pharmaceutical formulation. The chromatogram was run through Agilent C18 (150 × 4.6 mm, 5 m) column. Mobile phase containing 0.1% Ortho Phosphoric acid (OPA) (pH 2.4) and Acetonitrile in the ratio of 55:45 was pumped through the column at a flow rate of 0.75 ml/min. While the temperature was maintained at 30°C. The optimized wavelength for the combination was 245 nm. The retention time of DAR, COB, EMT, and TEN were found to be 3.988 min, 3.147 min, 2.205 min, and 2.616 min respectively. The linearity range for the method was found to be 200-1200µg/ml for DAR, 37.5-225 µg/ml for COB, 50-300 µg/ml for EMT and 2.5-15 µg/ml for TEN with regression coefficients of 0.9992, 0.9997, 0.9997 and 0.9994. The method was validated according to ICH guidelines and the drugs were subjected to forced degradation as per ICH Q1A15. Forced Degradation studies were performed on different conditions and the percentage of drug degraded was found to be within limits. The accuracy of the method was indicated by a good recovery in the range of DAR 99.87%, COB 99.41%, EMT 99.74%, and TEN 100%w/v. The developed and validated RP-HPLC method can be routinely used for the estimation of Darunavir (DAR), Cobicistat (COB), Emtricitabine (EMT), and Tenofovir alafenamide (TEN) in their bulk and pharmaceutical formulation.