Impact of Insulin Tregopil and Its Permeation Enhancer on Pharmacokinetics of Metformin in Healthy Volunteers: Randomized, Open-Label, Placebo-Controlled, Crossover Study.

Oral insulin tregopil (IN-105; a new drug under development) may be coadministered with oral antidiabetic drugs, such as metformin in patients with type 2 diabetes mellitus for optimal glycemic control. IN-105 has sodium caprate excipient, a permeation enhancer, for enhancing absorption in the stomach and increasing bioavailability via an oral route. Sodium caprate may increase bioavailability of metformin by a similar mechanism. Therefore, it was necessary to study the effect of IN-105 on pharmacokinetics (PKs) of metformin. In this randomized, open-label, cross-over study, metformin was administered to healthy volunteers receiving IN-105/placebo under fed/fasting conditions. The 90% confidence interval (CI) of the geometric mean ratio of the area under the curve from time zero to infinity (AUC ; fasting and fed) and peak plasma concentration (C ; fed) of metformin were within 0.80-1.25 acceptance range. Under fasting conditions, the upper bound margin of C was just beyond this range (i.e., 1.27) and was concluded as functionally not relevant. There was no clinically significant effect of sodium caprate/IN-105 on PKs of metformin under fasting/fed conditions, and it was safe.