Pharmacokinetic bioequivalence of sitagliptin phosphate tablet formulations: a randomized, open-label, crossover study in healthy volunteers

Introduction/Study Objectives: The aim of the current study is to assess the rate and extent of absorption of a test and reference formulation containing sitagliptin. Methods: An open -label, balanced, randomized, two -treatment, two -period, two -sequence crossover study was implemented to investigate the pharmacokinetic bioequivalence of a test and reference tablet products both containing a single dose of sitagliptin 100 mg in 28 healthy volunteers under fasting conditions. A total of twenty blood samples were obtained at pre -dose and multiple time intervals post -dose throughout the 48 hours sampling period. Sitagliptin concentrations were analysed using an LC-MS/MS validated method following a solid phase plasma extraction step. Sitagliptin pharmacokinetic parameters estimated with non -compartmental pharmacokinetic analysis were compared between the test and reference formulations with a multivariate analysis of variance. Results and discussion: The differences between the reference and test formulations in terms of area under the curve, 0 to infi nity (AUC (0-inf) ) , AUC( 0-48 ), and the maximum concentration (C max ) were found to be not signifi cant. The 90% confi dence intervals of sitagliptin Ln-transformed A UC (0-inf) , AUC (0-48 ), and C max , were within the pharmacokinetic bioequivalence acceptance range of 80%-125%. Conclusion: The test formulation of sitagliptin was bioequivalent in terms of exposure to the reference formulation in healthy volunteers under fasting conditions.