Relative bioavailability study of linagliptin/ metformin tablets in healthy Chinese subjects

OBJECTIVE: To evaluate the relative bioavailability of single pill combination (SPC) tablets of linagliptin and metformin compared with separate tablets co-administered in healthy Chinese subjects. MATERIALS AND METHODS: This was an open-label, single-dose, randomized, two-period, crossover study in healthy Chinese subjects with two dose groups: linagliptin 2.5 mg/metformin 850 mg and linagliptin 2.5 mg/metformin 500 mg. Within each group (n=24), subjects received one dose of the SPC tablet in one period and one dose of the separate tablets in the other. Primary endpoints were area under the plasma concentration-time curve from 0 to 72 hours (AUC0-72) and maximum plasma concentration (Cmax) for linagliptin, and AUC from 0 to the last quantifiable concentration (AUC0-tz) and Cmax for metformin. RESULTS: With the linagliptin 2.5 mg/metformin 850 mg dose, the adjusted geometric mean ratio of the SPC to the separate tablets for linagliptin was 99.53% (90% confidence interval (CI): 94.75-104.55) for AUC0-72 and 101.93% (90% CI: 95.36-108.95) for Cmax; for metformin the ratio was 96.99% (90% CI: 90.62-103.81) for AUC0-tz and 94.64% (90% CI: 85.43-104.84) for Cmax. With the linagliptin 2.5 mg/metformin 500 mg dose, the ratio with linagliptin for AUC0-72 and Cmax was 100.81% (90% CI: 95.14-106.82) and 111.37% (90% CI: 100.40-123.54), respectively; the same statistical parameters with metformin for AUC0-tz and Cmax were 102.95% (90% CI: 96.24-110.12) and 102.46% (90% CI: 92.20-113.87), respectively. CONCLUSIONS: SPC tablets of linagliptin and metformin were bioequivalent to separate tablets co-administered in healthy Chinese subjects.