Development and Validation of Bioanalytical Method for the Determination of Cobicistat from Human Plasma

A simple and sensitive bio-analytical RP-HPLC method with PDA detection was developed and validated for the quantification of cobicistat in human plasma. Febuxostat was used as an internal standard. The analytes were extracted from human plasma samples by liquid-liquid extraction technique. Chromatographic separation was accomplished with a Column Inertsil-BDS 250(I.D-4.6mm, particle size-5μm), Mobile phase composition 0.1% OPA Buffer: Acetonitrile (45:55), Flow rate: 1 ml/min, Injection volume 50 μl, Run time 10 min, Detection wavelength 210nm, PDA detector, Column temperature 30°C. The retention time of cobicistat and internal standard was found to be 4.0min and 5.4min respectively. The calibration curve obtained was linear (r2= 0.9992) over the concentration range of 0.01-10.0 μg/ml. The proposed method was validated by performing linearity, accuracy, precision, recovery, specificity, ruggedness (precision and accuracy), stability studies, reinjection reproducibility. The results were found to be within limits. The method was validated as per the USFDA guidelines. Hence the validated method is suitable for conducting pharmacokinetic studies and therapeutic drug monitoring.