Objective: Repaglinide is a novel prandial glucose regulator (PGR) for the treatment of type 2 diabetes. In order to investigate subject variability following oral administration of repaglinide, and to determine the relative and absolute bioavailabilities of repaglinide following oral or intravenous administration, two single-centre, open-label, randomized, crossover clinical studies were conducted.
Subjects and methods: Study 1 was conducted in 24 healthy male subjects (aged 18 to 49 years), who received repaglinide 2 mg, as either tablet or oral solution, twice each on 4 separate occasions at least 7 days apart. Study 2 was conducted in 12 healthy male subjects (aged 18 to 45 years), who received repaglinide 2 mg, either as a tablet or as an intravenous infusion over 15 minutes, once each on 2 separate occasions, with a washout period of 7-10 days.
Results: In study 1 there was no significant difference between administration of repaglinide 2 mg, in either tablet or oral solution form with regard to intrasubject variation in AUC and Cmax. However, the intrasubject variation in t(max) and mean residence time (MRT) was significantly (p = 0.001) larger for the tablets than for the oral solution. Intersubject variation (CV) in AUC ranged from 44.7% to 62.1% after oral administration. The relative bioavailability of repaglinide (AUC(tablet)/AUC(oral solution)) was 110% (95% CI, 103%-117%). In study 2 the absolute bioavailability of repaglinide administered as a tablet was 62.5% (95% CI, 49.2%-79.5%) relative to an intravenous infusion of the same dose.
Conclusion: There was no evidence from either study that the tablet formulation led to greater variation in serum profiles of repaglinide. It was concluded that repaglinide is rapidly absorbed and eliminated in healthy subjects when administered orally or intravenously under fasting conditions, and that the total availability of repaglinide is similar in the tablet and oral solution formulations, though that the rate of absorption is slower for the tablet formulation.