Sample Enrichment of Canagliflozin Prior to Its Spectrophotometric Determination in Presence of Metformin: Application to Recently Approved Binary Dosage Form

This work illustrates four different spectrophotometric methods for metformin ( MET ) and canagliflozin ( CANA ) quantification in their recently approved pharmaceutical with trade name Invokamet ® . The proposed methods are simple, definitive and accurate. Certain ensuing steps implementing zero spectra and/or ratio and/or derivative spectra were applied. Via implementing spectrum subtraction method accompanied with constant multiplication, zero order spectra were obtained for these drugs followed by their determination at their correlated λ max at 237 and 290 nm for MET and CANA, respectively. Meanwhile, through employing method of derivative subtraction the two drugs were obtained in their first derivative spectra and quantified at 242.7 and 319.0 nm for MET and CANA, respectively. The suggested methods were inspected via laboratory prepared (diverse ratios) mixtures and they were excellently applied for analysis of Invokamet ® tablets. Moreover, sample enrichment via spiking technique was elected for a pharmaceutical formulation analysis containing CANA as a minor component. Accuracy, precision and specificity were between the valid limits. Validation steps were done in accordance with the ICH guidelines. Also, statistical compression was carried out between the obtained and reported results and no crucial divergence appeared.