Spectrophotometric Estimation of Emtricitabine and Tenofovir Disoproxil Fumarate in Tablet Dosage form by Simultaneous Equation and Absorbance Ratio Methods

Two methods for simultaneous determination of Emtricitabine and Tenofovir Disoproxil Fumarate by spectroscopy have been developed. First method is Simultaneous equation method and second method is Absorbance ratio Method. From a solvent effect studies and the spectral behaviours of Emtricitabine and Tenofovir Disoproxil Fumarate, methanol was selected as solvent. Emtricitabine shows maximum absorbance at 281 nm and Tenofovir Disoproxil Fumarate shows maximum absorbance at 259 nm. Linearity in concentration range of 6-48 μg/mL and 4-32 μg/ mL was shown for Tenofovir Disoproxil Fumarate and Emtricitabine, respectively. In the first method, the concentration of the drugs were determined by using simultaneous equation and in second method the concentration of drugs were determined by using ratio of absorbances at isoabsorptive point and at the ëmax of one of the drug. The results of analysis were validated statistically and by recovery studies. Tablet containing both drugs was assayed using the methods developed, showing a good accuracy and precision.