Physicochemical interactions of metformin hydrochloride and glibenclamide with several health foods.

In this study, as an approach to possible pharmacokinetic interactions between antidiabetic agents and health foods, we investigated the binding of metformin and glibenclamide to aojiru, kurosu, and blueberry extract using a dialysis method. The permeation of metformin from the inner to the outer side of the dialysis tube during 90 min was not altered in the presence of aojiru or kurosu, and slightly decreased by 20% compared with the control in the presence of blueberry extract, indicating that the interactions between metformin and these three health foods are limited. On the other hand, when these three health foods were added to inner medium together with glibenclamide, they significantly lowered the outer glibenclamide concentrations. The magnitude of the decrease in the outer glibenclamide concentrations was the most extensive in the presence of kurosu (60%), followed by aojiru (36%) and blueberry extract (45%). The present results suggest that metformin and glibenclamide interact differently with aojiru, kurosu, and blueberry extract and that these three health foods might modulate the absorption of glibenclamide in vivo.