An open-label, randomized, single-dose, two-period, two-group, crossover study was conducted in 48 healthy Chinese volunteers under fasted or fed conditions (24 volunteers for each condition) to assess the bioequivalence between two formulations of Sitagliptin Phosphate/metformin Hydrochloride Tablets.

The single-dose randomized, open-label, two-period crossover study was executed in the Phase I Clinical Research Center of the Affiliated Hospital of Qingdao University. This study was conducted to assess the bioequivalence of Sitagliptin Phosphate/metformin Hydrochloride Tablets in healthy Chinese subjects and estimate the pharmacokinetics profiles of Sitagliptin Phosphate/metformin Hydrochloride Tablets. An open-label, randomized, single-dose, two-period, crossover study was conducted in 48 healthy Chinese volunteers under fasted or fed conditions (24 subjects for each condition) to assess the bioequivalence between two formulations of Sitagliptin Phosphate/metformin Hydrochloride Tablets. Blood samples were collected at specified time intervals, and the plasma concentrations of sitagliptin and metformin were determined by a validated liquid chromatography mass spectrum/ mass spectrum method. Pharmacokinetic and bioavailability parameters were estimated via non-compartmental methods. Adverse events were also recorded. If the 90% confidence intervals of the ratios of geometrical mean of test and reference formulations for Cmax, AUC0-t and AUC0-∞ are all within the predefined bioequivalence criteria range of 80%-125% for sitagliptin and metformin, the two formulations can be considered bioequivalent.

Inclusion Criteria:

• Healthy male or female aged between 18 and 45 years old (including the critical value).
• The body mass index is in the range of 19-28 kg/m2 (including the critical value). The weight of male is not less than 50 kg, and that of female is not less than 45 kg (including the critical value).
• Subjects who had not any medical history of cardiovascular, digestive, respiratory, nervous or hepatic/renal impairment. The following examination show that the indicators are normal or abnormal without clinical significance. The examination including: physical examination, 12-lead ECG, vital sign measurements, and laboratory safety tests.
• The subjects have no family planning within 6 months and could select contraceptive method.
• Before the study, all subjects have been informed of the study's purpose, protocol, benefits, and risks, and signed the informed consent voluntarily.
• The subjects could complete the study according to the protocol.

Exclusion Criteria:

• Being allergy to the study medications, smoking, alcohol abuse.
• Participation in another clinical trial within 3 months.
• Any history of hypersensitivity, needlesickness or idiosyncratic reactions to any food or drug;
• Any use of other prescription drugs (including contraceptive) 14 days prior to medication for this study;
• Any use of prescription or over-the-counter drugs, functional vitamin, herbal/ alcohol products, grapefruit-containing or caffeine/xanthine-rich food and beverages 48 h prior to medication for this study; dysphagia or having special dietary requirements;
• occurring acute disease in the screening period or before the medication lactating or pregnant women;