Bioavailability and pharmacodynamics of a sustained-release glibenclamide product (Deroctyl) in comparison to a standard tablet formulation (Euglucon, Daonil).

Pharmacodynamics and tolerance, as well as the bioavailability of two oral dosage forms of 5 mg glibenclamide were determined in eight healthy male volunteers in a double-blind crossover study. These preparations were Euglucon (regular tablets) and Deroctyl (sustained-release capsules). Blood glucose levels were determined by the hexokinase method and serum glibenclamide, insulin, and C-peptide levels by radioimmunoassay. Following Deroctyl both the rate and extent of absorption of glibenclamide and therefore its serum levels were much lower than that observed after the same dose of Euglucon. The differences between Cmax, AUC0-4, AUC0-8, and AUC0-24 were statistically significant. For glucose, only Cmin values were found to be significantly lower following Euglucon. For insulin AUC0-8 and AUC4-8 values and for C-peptide AUC0-4 and AUC0-8 values were found to be significantly greater following Euglucon. A single oral dose of either preparation was well tolerated and no side effects occurred. It is concluded that Derocytl is not bioequivalent to Euglucon: its relative bioavailability is only 62.5% (AUC0-24).