Stability Indicating RP-HPLC Method for the Simultaneous Determination of Darunavir and Cobicistat in Bulk and Pharmaceutical Dosage form

Abstract

A simple, sensitive and precise stability indicating RP-HPLC method has been developed and validated for the simultaneous estimation of darunavir and cobicistat in combined dosage form. The column used was Inertsil ODS (4.6 x 150mm, 5mm) column. The mobile phase used was Phosphate buffer: Methanol: Acetonitrile (40:20:40). Quantification was carried out using PDA Detector at 239 nm. Linearity was found to be 50-250 mcg/ml for darunavir and 10-50 mcg/ml for cobicistat, respectively. The method was validated for system suitability, precision, accuracy, ruggedness, robustness, LOD & LOQ. Darunavir and cobicistat were also subjected to acid degradation, alkali degradation, oxidative degradation, thermal degradation and photo degradation. The degradation products obtained were well resolved from the darunavir and cobicistat with different retention times. Since the method can effectively separate darunavir and cobicistat in their combined dosage form, it can be used for the routine determination of darunavir and cobicistat.