NEW SENSITIVE UV SPECTROPHOTOMETRIC METHODS FOR SIMULTANEOUS ESTIMATION OF ZIDOVUDINE AND LAMIVUDINE IN FIXED DOSE COMBINATION

Two new, simple, accurate and sensitive UV spectrophotometric methods have been developed and subsequently validated for the simultaneous estimation of zidovudine and lamivudine in a fixed dose combination. Zidovudine and lamivudine have an absorption maxima at 267.3 nm and 272.3 nm respectively. The first method is based upon the simultaneous equation and second upon the determination of Q value. The simultaneous estimation method is based upon the measurements of ratios of absorptivity and absorbance, of both the components at their absorption maxima. The method of Q analysis is based on the measurement of ratios of absorptivity and absorbance, of both components at two selected wavelengths; one is an isoabsorptive point i.e. 270.1 nm and other being the wave length maxima of any of the two components, say λmax of zidovudine i.e. 267.3 nm. Both zidovudine and lamivudine shows linearity over the concentration range of 4-12 ppm at their respective absorption maxima and at isoabsorptive point. The assay and recovery studies from fixed dose combination as tablet dosage form are indicative of accuracy of the proposed methods. The developed methods were validated in accordance to International Conference on Harmonization (ICH) guidelines for linearity, range, accuracy and precision.