Interaction of a herbomineral preparation D-400, with oral hypoglycaemic drugs.

D-400, a herbomineral preparation has proven antidiabetic activity in experimental models as well as in clinical trials. The possibility of concomitant use of this drug with sulphonylureas was explored in animal models. D-400 has been investigated for its interaction with oral hypoglycaemic agents namely, tolbutamide and glibenclamide in alloxan-induced diabetic rabbits. Administration of D-400 at a dose of 1 g/kg for 15 days significantly elevated plasma tolbutamide and glibenclamide concentrations with simultaneous reduction of blood glucose. Plasma tolbutamide and glibenclamide concentrations were significantly lowered after withdrawal of D-400 treatment. Elevation of plasma concentration of tolbutamide was observed only for the first 4 h after which it declined towards normal levels and no significant difference between D-400 treated and control group was observed at the end of 8 h. Significant elevation of plasma glibenclamide levels was observed at 2, 4 and 8 h with D-400 treatment. Incubation of D-400 with tolbutamide in plasma resulted in a significant increase in free tolbutamide levels.