Author(s): KS. Sumanth1* , A. Srinivasa Rao2 and D. Gowri Shankar3
A new, simple, rapid and accurate RP-HPLC method was developed for the estimation of Efavirenz (EFA) in human plasma and validated. The method was developed on SHISEIDO C18 column (250 x 4.6 mm i.d, 5µ) using Acetonitrile : 20 mM phosphate buffer (pH 3.0). The wavelength used for detection of EFA is at 247 nm. The flow rate used for the elution is 1 ml/min. sample preparation for the extraction of drug was done using solid phase extraction method by Phenomenex STRATA® C18 sorbent, a 24 station SPE vacuum extraction assembly is used for the entire method. Methyl prednisolone was used as internal standard, the retention time of Efavirenz and internal standard were found to be 5.7 and 3.7 min respectively. Linearity was established in the range of 0.43 – 8.60 µg/ml and the coefficient of regression (R2) value was found to be 0.995, having 0.037 as slope. The method was precise with %RSD < 2 for both intraday and interday precision. The accuracy of the method was performed over three levels of concentration and the recovery was in the range of 98- 102%. The method can be successfully applied for quantifying the drug in human plasma for bioavailability and bioequivalence studies.