Spectrophotometric Determination of Metformin in Different Pharmaceutical Combinations With Glipizide or Sitagliptin in Presence of Toxic Impurities of Metformin.

Novel application of quadruple divisor spectrophotometric technique is introduced for resolving mixtures containing five components with severely overlapping spectra. A simple and sensitive spectrophotometric method was developed for simultaneous determination of metformin, glipizide, and sitagliptin in the presence of metformin potential impurities melamine and cyanoguanidine. The validity of the proposed method was revealed as per ICH guidelines.