Efavirenz

A simple, accurate and precise UV spectrophotometric method has been developed for the quantitative estimation of Efavirenz in bulk and tablet dosage form. The λmax was found to be 239 nm. Beer’s law was obeyed in the concentration range of 10-20μg/ml. The regression equation was Y=0.052x-0.113 with value of R2 as 0.996. The method showed good linearity, accuracy and reproducibility. Accuracy as expressed mean percent recovery ± standard deviation was found to be 95.29% ± 0.0429. Percent relative standard deviation values for the intra-day and inter-day precision studies were found to be 0.23 and 0.31, respectively. The limit of detection and limit of quantitation values were found to be 1.39 and 4.22, respectively. Assay of Efavirenz in tablet formulation was performed and percent purity of tablet was found to be 98.65% ± 0.0078.

An accurate, precise and reproducible high performance liquid chromatographic method was developed for quantitative estimation of emtricitabine, efavirenz and tenofovir disoproxil fumarate simultaneously in tablet dosage forms. Separation of the drugs was achieved within 15.0 min on a Xterra RP-18 column (150 x 4.6 mm; 5µ) by gradient elution using mixtures of ammonium acetate buffer and acetonitrile as the mobile phase. The analytes in the eluate were monitored at 260 nm. The retention times obtained for emtricitabine, efavirenz and tenofovir disoproxil fumarate were 4.611, 9.098 and 7.512 min respectively. The calibration curves were linear over the range of 20.11-60.33 µg/mL for emtricitabine, 60.28-180.45 µg/mL for efavirenz and 30.13-90.18 µg/mL for tenofovir disoproxil fumarate. The performance of the method was validated according to ICH guidelines. The method was found to be suitable for accurate determination of these drugs in tablet dosage forms without any interference from excipients or endogenous substances.