MICROEMULSIONS AS ANTIDIABETIC DRUG DELIVERY SYSTEMS

Glibenclamide is practically insoluble in water and its gastrointestinal absorption is limited by its dissolution rate. Therefore, to enhance the drug dissolution and its hypoglycemic effects, the drug was formulated in different microemulsion systems and in vitro/in vivo evaluated. Microemulsion systems were prepared by Water titration method in which surfactants and cosurfactants (S/Co_S) were mixed at different weight ratios of 1:1, 2:1 and 3:1. They were subjected to transmission electron microscopical examination, pH determination and viscosity tests. The solubility of Glibenclamide in different microemulsion systems was determined. Forms 8, 9, 10, 11, 14 and 18 were found to have high Glibenclamide solubility using different oils. Form 11 and 9 showed the highest Glibenclamide release rates of 59.72% and 52.35%, respectively after 6 hours. In-vivo studies were tested using diabetic rats by application of form 11 with n-butanol as cosurfactant transdermally and form 8 with propylene glycol cosurfactant orally and transdermally. The results were compared to the drug suspension as a positive control. It was shown that microemulsion systems gave an effective tool of increasing drug dissolution probably due to enhanced wettability and reduced drug particle size, which in turn led to enhance its hypoglycemic effects.