In vitro and in vivo evaluation of glibenclamide in solid dispersion systems

The purpose of this work is to improve the dissolution and bioavailability characteristics of glibenclamide as compared to Daonil tablets (Hoechst). Solid dispersions of glibenclamide in Gelucire 44/14 (Formula 1) and in polyethylene glycol 6000 (PEG 6000) (Formula 2) were prepared by fusion method. In vitro dissolution studies showed that the dispersing systems containing glibenclamide and Gelucire 44/ 14 or PEG 6000 gave faster dissolution rates than the reference product Daonil. The in vivo bioavailability study was assessed in six healthy male volunteers in crossover design with a 1-week washout period. Both formulas were found to be significantly different from Daonil with regard to the extent of absorption as indicated by the area under serum concentration-time curve. Both formulas are not significantly different from Daonil with respect to time of peak plasma concentration Tmax. It is concluded from this pilot study that the ranking of the in vitro dissolution is similar to the ranking of in vivo availability. The ranking of the three preparations in term of dissolution rate and extent of absorption is as follows: Formula 2>Formula 1 >Daonil.