Development and Validation of RP-HPLC method for Simultaneous estimation of Atazanavir and Ritonavir in their combined tablet dosage form

Atazanavir and Ritonavir are antiviral agents used in treatment of HIV. A simple, precise, rapid, accurate and cost effective high performance liquid chromatography (HPLC) method was successfully developed and validated for simultaneous estimation of Atazanavir and Ritonavir in their combined tablet dosage form. Chromatographic separation was achieved on a Thermo Hypersil C18 (250 × 4.6 mm, 5 μ) in isocratic mode using 0.05M KH₂PO₄ buffer pH adjusted to 3.0 ± 0.05 with orthophosphoric acid and acetonitrile in the proportion of 45:55 (v/v) as the mobile phase at a flow rate 1.0 ml/min. Quantitation was achieved with UV detection at 254 nm. In the proposed HPLC method, quantification was achieved over the concentration range of 150–360 μg/mL and 50–120 μg/mL, with mean recoveries in range of 99.5–101.4% and 99.7–101.6% for Atazanavir and Ritonavir respectively. The proposed methods were successfully applied for the analysis of synthetic mixtures and pharmaceutical formulations of Atazanavir and Ritonavir without any interference from excipients.