An efficient RP-HPLC-based approach for simultaneous determination of sitagliptin and metformin HCl in pharmaceutical drug formulation.

This study introduces an innovative, and rapid HPLC method using reverse phase elution for the simultaneous analysis of Sitagliptin and Metformin HCl in pharmaceutical formulations. This combination was explored in bulk and solid dosage forms using Luna Phenomenex C8 column (4.6 x 250 mm, 5 µm) at ambient temperature in isocratic elution. It was found that the mobile phase comprising of 0.1% ortho-phosphoric acid, potassium dihydrogen phosphate buffer (pH 3.0) and acetonitrile in ratios 35:35:30, showed a symmetrical peak for Sitagliptin and Metformin HCl. The detection was carried out at 210nm, using a flow rate of 1.0mL/min. The method was linear over the concentration range for Sitagliptin 2.5-7.5 ppm and Metformin HCl 25-75 ppm. The assay recoveries of Sitagliptin and Metformin were found to be 100.36% and 100.20%, respectively. The LOD and LOQ for the Sitagliptin were found to be 0.201 ppm and 0.301 ppm and for Metformin HCl 0.101 ppm and 0.303 ppm, respectively. The proposed methods can be implemented for controlling quality in bulk and solid dosage forms. The analytical methods were validated as per the guideline of ICH Q2 (R2). The developed HPLC methods were effectively employed for the determination of combined dosage forms in pharmaceutical formulations.