Bioequivalence of Sitagliptin/Metformin Fixed-Dose Combination Tablets and Concomitant Administration of Sitagliptin and Metformin in Healthy Adult Subjects A Randomized, Open-Label, Crossover Study

Background: Treatment with an oral antihyperglycaemic agent administered as monotherapy is often unsuccessful at achieving or maintaining glycaemic control in patients with type 2 diabetes mellitus. The combined use of sitagliptin and metformin is an effective treatment for type 2 diabetes mellitus, consistent with the complementary mechanisms of action by which these two agents improve glucose control. Objectives: To establish bioequivalence between sitagliptin/metformin fixeddose combination (FDC) tablets (Janumet � ) and co-administration of corresponding doses of sitagliptin and metformin as individual tablets. Methods: This was an randomized, open-label, two-part, two-period crossover study, which included a total of 48 healthy subjects, 24 subjects per part (parts I and II). Within each part, subjects were assigned to receive treatments in random order; treatment periods were separated by a washout interval of at least 7 days. Eligible study participants included healthy, non-smoking (within previous 6 months), male and female subjects aged between 18 and 45 years with a body mass index £32 kg/m 2 .P art Ic onsisted of treatments A( coadministration of sitagliptin 50 mg and metformin 500 mg) and B (sitagliptin/ metformin 50 mg/500 mg FDC tablet); part II consisted of treatments C (co-administration of sitagliptin 50 mg and metformin 1000 mg) and D (sitagliptin 50 mg/metformin 1000 mg FDC tablet). Blood samples were collected pre-dose and up to 72 hours post-dose in each treatment period for determination of plasma sitagliptin and metformin concentrations and calculation of the respective pharmacokinetic parameters. The area under the plasma concentration-time curve from time zero to infinity (AUC¥) and the maximum plasma concentration (Cmax) for both