An isocratic reversed phase ultra performance liquid chromatographic (UPLC) method was developed for the simultaneous determination of Atazanavir sulphate (ATV) and Cobicistat (COBI) in drug product and drug samples. Waters (Alliance) UPLC system equipped with auto sampler and photo diode array (PDA) detector were adopted in method development. The developed method was optimized by varying one of chromatographic conditions such as mobile phase, composition of mobile phase, flow rate and run time keeping other constant. Precisely 5 μl of standard is introduced into Endeavorsil C18 50 mm x 2.1 mm, 1.8 μm particle size (Make: Dikma technologies) column kept at temperature of 400C, and the components were separated by introducing mixture of 0.1% orthophosphoric acid buffer of pH 5.5, methanol and acetonitrile in the ratio 27:18:55 v/v as mobile phase at a flow rate of 0.27 ml/min. The components were detected at a wavelength of 245 nm. Retention time, peak area, peak height, plate count and tailing factor for COBI and ATV were found to be 0.443 & 0.619, 104642 & 1100159, 45941 & 515268, 2237 & 2935, 1.1 & 1.2 respectively. The developed method was validated as per international conference on harmonization (ICH) guidelines, and assay of Evotaz was determined and found to be 100.82%. The stability of the drug sample was examined in different degradation conditions like 0.1N hydrochloric acid (HCl), 0.1N sodium hydroxide (NaOH), 3% hydrogen peroxide (H2O2), photo light and thermal conditions and the range of percent of degradation was found to be 5.2-18.4%. The developed method was found to be simple, rapid and applied for the analysis of drug samples, therefore the proposed method is recommended for the assay analysis of COBI and ATV in pure and tablet dosage forms in any quality control laboratories.
