Determination of Sitagliptin Phosphate in Bulk Drugs by Extractive Spectrophotometric Method

An extractive spectrophotometric method is described for the assay of sitagliptin phosphate in bulk drug and in tablets. Sitagliptin phosphatewas extracted as an ion-pair complex from the solution containing Eriochrome black T and 0. IN HC1 into chloroform and the absorbance of the complex was measured at 500nm.The working conditions of the method were investigated and optimized. Beer s law plot showed a good correlation in the concentration range of 1—25 |ng ml1. Sensitivity indices such as molar absorptivity, Sandell s sensitivity, limits of detection and quantification are reported.Precision and accuracy of the methods were established. The method was successfully applied to the assay of sitagliptin phosphate in tablet dosage forms with recoveries varying from 99.70 to 101.23% and standard deviation from 0.428 to 0.983. The results were statistically compared with those of the reference method.