ABSTRACT:
A new, simple, precise and stability-indicating UPLC (Ultra Performance Liquid Chromatography) method was developed and validated for the simultaneous determination of anti-viral drugs Cobicistat and Darunavir. The method was developed using Acquity UPLC HSS C18 x 1.8 m.with isocratic elution. 0.1% orthophosphoric acid buffer and acetonitrile (35:65 v/v) were used as mobile phase with 0.4 ml/min flow rate at 30°C temperature. The detection wavelength was fixed at 250 nm, the run time was within 2 min. The Retention time of Cobicistat and Darunavir were 1.06 and 0.79 min respectively. The method was validated in terms of linearity, precision, accuracy and robustness. Calibration plots were linear over the range of 7.5-45 µg/ml for Cobicistat and 40-240 µg/ml for Darunavir. Recovery was in the range of 98-102% with the relative standard deviation of less than 2% for both drugs. The limit of detection and the limit of quantification for the Cobicistat were found to be 0.161 and 0.488 µg/ml, respectively, and for Darunavir 0.55 and 1.67 µg/ml respectively. The specificity of the method was analyzed by the stress degradation study in acidic, alkaline, oxidative, thermal, UV and hydrolytic conditions. The suggested method was suitable for determination of Cobicistat in bulk and pharmaceutical dosage forms.