Abstract

Two simple, rapid, accurate and economical methods have been developed for the simultaneous estimation of metformin and repaglinide in the synthetic mixture. The linearity was observed in the concentration range of 4-24 µg/ml for the both metformin and repaglinide. First method is based on the simultaneous equations, absorbances of both the drugs were determined at 240 nm (λ max of metformin) and at 291.5 nm (λ max of repaglinide). Metformin does not show any absorbance at 291.5 nm, hence its absorptivity was taken zero in the calculation. The method was validated in terms of accuracy (99.24±0.99, 100.98±0.89) and precision (intra-day variations 0.58-1.21, 2.12-3.12 and inter-day variations 0.62-1.42, 2.20-3.08). Second method is based on Q-absorbance ratio; absorbances of both the drugs were determined at 240 nm (l max of metformin) and at isoabsorptive point (254.8 nm). Q-absorption ratio method was validated in terms of accuracy (98.57±1.05, 98.62±1.2402) and precision (intra-day variations 0.58-1.21, 1.01-3.53 and inter-day variations 0.62-1.42, 1.15-3.74). The proposed methods were found accurate, reproducible and economical for the routine analysis of both the drugs in the synthetic mixture.