Stability-indicating Liquid Chromatographic Method for the Simultaneous Determination of Atazanavir and Ritonavir in Pharmaceutical Formulation

University College of Pharmaceutical Sciences, Andhra University, Visakhapatnam 530 003, Andhra Pradesh, India ABSTRACT: A simple, rapid, precise and accurate isocratic reversedphase stability-indicating HPLC method was developed and validated for the simultaneous determination of Atazanavir (AT) and Ritonavir (RT) in commercial tablets. The method has shown adequate separation for AT, RT from their degradation products. Separation was achieved on a Hypersil BDS-C18, 5 μm, 125 mm × 4.6 mm i.d. column using a mobile phase consisting of buffer (pH3.4) – acetonitrile (50:50, v/v) at a flow rate of 1.5 mL/min and UV detection at 250 nm. The drugs were subjected to oxidation, acid, base hydrolysis, photolysis and heat to apply stress conditions. The linearity of the proposed method was investigated in the range of 7.8–225 μg/mL (r 2 = 0.9993) for AT and 2.7-75 μg/mL (r 2 = 0.9995) for RT. The limit of detection was 2.4 μg/mL for AT and 0.9 μg/mL for RT. The limit of quantitation was 7.8 μg/mL for AT and 2.7 μg/mL for RT. Degradation products produced as a result of stress studies did not interfere with the detection of AT and RT and the assay can thus be considered stability-indicating.