QbD based RP-HPLC method for simultaneous determination of a emtricitabine, tenofovir diproxil fumarate and efavirenz in tablet dosage form-an application to stability indicating assay

Abstract The current studies entail Quality by Design (QbD)-enabled development of a simple, rapid, sensitive and cost-effective high-performance liquid chromatographic method for estimation of emtricitabine (EMT), tenofovir diproxil fumarate (TEN), and efavirenz (EFA) in combined dosage form. Systematic optimization was performed employing Box-Behnken design by selecting the flow rate, buffer molarity, and acetonitrile volume as the critical method parameters (CMPs) identified from screening studies, thus evaluating the critical analytical attributes (CAAs), namely, retention duration, theoretical plates, resolution, and asymmetry factor as the parameters of method robustness. The optimal chromatographic separation was achieved using acetonitrile and phosphate buffer (pH 3.0) 74.1:25.9 v/v as the mobile phase with a flow rate 0.91 mL/min, and UV detection at 260 nm. The method was validated as per the ICH recommended conditions, which revealed high degree of linearity, accuracy, precision, sensitivity and robustness over the existing liquid chromatographic methods of the drug. Studies on forced degradation under acid, basic, oxidative, photolytic, and thermal conditions revealed the drug’s well-resolved peak and the degradation products’ peaks as well. GRAPHICAL ABSTRACT