Pharmacokinetics and Effects of Glibenclamide in Two Formulations, HB 419 and HB 420, in Type 2 Diabetes

The pharmacokinetics and effects of glibenclamide in two formulations, the established formulation, HB 419 (5 mg) and the new micronized formulation, HB 420 (3.5 mg) were compared after once daily administration of each to eight type 2 diabetics in a double blind crossover trial. On the second day of administration of each formulation, blood glucose and serum C-peptide, insulin and glibenclamide concentrations (radioimmunoassays) were measured for eight hours after tablet ingestion. Although the amount of glibenclamide per tablet of HB 420 was lower than the amount of glibenclamide per tablet of HB 419, serum concentrations of drug were higher after HB 420 than after HB 419, and were also less variable between individuals. However, there were no corresponding differences in serum C-peptide and insulin levels, or in blood glucose levels. Thus intestinal absorption of glibenclamide appeared to be greater and less variable from HB 420 than from HB 419 but both formulations apparently produced drug concentrations in the serum well above that needed for maximum therapeutic response in the patients studied.