A rapid, simple, accurate and precise UV spectrophotometric Q-absorption ratio method was developed and validated as per the ICH-Q2 guidelines for the simultaneous estimation of Metformin and Canagliflozin. The method involved Q-absorption ratio analysis using two wavelengths obtained by the overlay spectrum of the Metformin and Canagliflozin, with one being the maximum absorbance wavelength of Canagliflozin (220 nm, 2) and the other being the iso-absorptive point of both drugs (250 nm, 1). The method was validated as per ICH guidelines. Linearity and range were determined by analyzing six independent concentration levels of calibration curve in the range of 5-17.5 ?g/mL for Metformin and Canagliflozin respectively (n=3). The value of correlation coefficient was > 0.99 for each of Metformin and Canagliflozin at 220nm and 250 nm. Accuracy of the method was confirmed by recovery study from marketed formulation at three levels â 80,100 and 120% of standard addition; the accuracy ranged between 99.63 and 101.14%. Intra-day and inter-day precision of Metformin and Canagliflozin was determined for three concentrations 5, 10 and 17.5 ?g/mL at 220 nm, 240 nm and 250 nm; and % CV was <1.0%. The proposed UV spectrophotometric Q-absorption ratio method is rapid, simple, precise, reproducible and economical that can be successfully employed for the industrial analysis of the combination of Metformin and Canagliflozin.
