Simultaneous Estimation of Tenofovir Disoproxil Fumarate, Efavirenz and Lamivudine in Fixed Dose Combination Tablets by Ultraviolet Spectrophotometry in Multicomponent Mode and its Application in Rat Plasma

A simple and sensitive UV spectrophotmetric method using multi-component mode was developed for the simultaneous estimation of tenofovir disoproxil fumarate, efavirenz and lamivudine in fixed dose combination tablets using a mixture of phosphate buffer pH 5 and methanol (50:50 %v/v) as solvent system. The detection was carried out at 247.0, 271.8 and 260.4 nm for efavirenz, tenofovir disoproxil fumarate and lamivudine respectively. Linearity was observed over concentration range of 0.4-24, 0.2-12 and 0.2-12 μg/mL for efavirenz, tenofovir disoproxil fumarate and lamivudine respectively and the coefficient of determination was found to be 0.999 for all three drugs. The developed method was validated as per ICH guidelines and all the parameters are within the limits. The limit of quantitation values was found to be 0.192μg/ml, 0.198μg/ml and 0.385μg/ml for efavirenz, tenofovir disoproxil fumarate and lamivudine respectively and reflects the sensitivity of the method. The developed method was optimised and applied in spiked rat plasma.