DEVELOPMENT AND VALIDATION OF A NEW RP-HPLC METHOD FOR SIMULTANEOUS DETERMINATION OF ANTIRETROVIRAL DRUGS: COBICISTAT AND ELVITEGRAVIR

A simple, precise, rapid and accurate reverse phase HPLC method was developed for the simultaneous estimation of cobicistat and elvitegravir in the pharmaceutical dosage form. A column of ODS (250mm 4.6mm; i.d and 5µ particle size) was used along with the mobile phase comprising of 0.02M dipotassium hydrogen orthophosphate buffer (pH adjusted to 3.3) and methanol in the ratio of 80:20 (v/v). The flow rate was maintained at 1.0 ml/min and the effluents monitored at 254 nm. The retention time for cobicistat was found to be 2.58 ± 0.3 min and elvitegravir was 3.71 ± 0.3 min. The detection concentration was linear over 125-750 µg/ml for cobicistat and 12.5-75 µg/ml for elvitegravir. Regression equations of cobicistat and elvitegravir were found to be y = 25883x + 19711 and y = 27696x + 6046 respectively with regression co-efficient 0.999. The % RSD for Intra and Inter day precision was < 2%. The accuracy of method was validated by recovery studies and found to be significant within acceptable range 98-102%. The developed method was successfully validated in accordance with ICH guidelines. The present study demonstrates the applicability of chromatographic method to develop a new, sensitive, single RP-HPLC method for the simultaneous quantitative determination of cobicistat and elvitegravir in fixed pharmaceutical dosage form. Hence, this method can be conveniently adopted for routine analysis in quality control laboratories.