Development and Validation of Stability-Indicating HPLC-DAD Method for Simultaneous Determination of Emtricitabine, Elvetegravir, Cobicistat and Tenofovir in their Tablet Dosage Forms

  A Simple, accurate, specific and rugged reverse phase liquid chromatographic method was developed for the simultaneous estimation of Emtricitabine, Elvetigravir, Cobicistat and Tenofovir in bulk and tablet dosage form. A reverse phase gradient program has been developed to separate the all four active ingredients. The mobile phase consisting of 0.05M Phosphate buffer pH 3.0 (adjusted with dilute phosphoric acid) and Acetonitrile in the ratio 95:5 from 0 min to 4 minutes, further increased the Acetonitrile ratio from 5 to 50 from 4 min to 10 minutes, on a reverse phase C18 column (250x4.6mm, 5 µ) with a flow rate of 1.0 ml/min, monitored at 240nm. The mean retention times of Emtricitabine, Elvetigravir, Cobicistat and Tenofovir were found to be 1.5, 5.4, 6.6 and 7.5 min respectively. The proposed method was validated in terms of Linearity, Range, Accuracy, Precision, Specificity, Robustness and Ruggedness and the method was successfully applied for the estimation of Emtricitabine, Elvetigravir, Cobicistat and Tenofovir in combined tablet dosage form.