Overweight and obesity are major health concerns worldwide, and are major predisposing factors for type 2 diabetes. This single-centre, Phase I, randomised, open-label, single-dose, 4-arm crossover, device-drug interaction study on 24 healthy volunteers with a body mass index of 25-40 kg/m tested the effect of a novel, nonsystemic, orally administered hydrogel (GS100) on the pharmacokinetics of an oral antidiabetic drug, metformin. When administered in both the fed and fasted states, the effect of GS100 on metformin pharmacokinetic characteristics was found to be similar to that of food. The type, frequency, and intensity of adverse events observed when GS100 was co-administered with metformin were similar to those observed with metformin alone. This study demonstrates that GS100 can be taken by patients receiving metformin, without altering the administration of metformin.