Simultaneous determination of sitagliptin and metformin in their pharmaceutical formulation.

Two simple, accurate, and rapid methods were developed for simultaneous determination of sitagliptin phosphate and metformin hydrochloride in their pharmaceutical formulation. The first is a TLC method coupled with densitometry. The second is an HPLC method using a C18 column. The selectivity of the proposed methods was checked using laboratory-prepared mixtures. The proposed methods were successfully applied to the analysis of sitagliptin phosphate and metformin hydrochloride in bulk form and in their pharmaceutical formulation without interference from other additives.