Microemulsion Based Formulation as Drug Delivery System for Gliclazide

Purpose: The present study is intended to develop and evaluate oil in water (O/W) microemulsion based formulation for gliclazide as oral drug delivery system for the treatment of diabetes mellitus. Gliclazide, having sulphonyl urea moiety (Class II of BCS system) is a hydrophobic drug. Methods: Oil in water microemulsion was formulated using water titration method. Viscosity, pH, conductivity, particle size and thermodynamic stability studies were carried out for optimization followed by In vitro drug release and in vivo pharmacokinetic study. Results: The formulated O/W microemulsion had olive oil, tween 80 and propylene glycol as ingredients with an average particle size 14.3 nm. The developed formulation showed a drug release of 82.4% while the pure drug in powdered form showed a release of 32.19% as observed through in vitro drug release studies. The data obtained by these studies was fitted to zero order, first order Higuchi and Korsmeyer Pappas models. The in vivo pharmacokinetic parameters of the optimized microemulsion was significantly (P<0.05) different when compared to the conventional tablet formulation. The peak serum concentration (C-max) for the microemulsion (2.998 +/- 0.419 mu g/mL) was higher than that for the conventional tablet (2.118 +/- 0.169 mu g/mL), and the time required to reach the peak serum concentration (T-max) was significantly shorter for the optimized microemulsion (2.5 +/- 0.548 h) compared to the tablet formulation (5.333 +/- 1.033 h). Conclusion: Gliclazide O/W microemulsion was found to be stable and showed superior in vitro and in vivo release. The study promises improved clinical efficacy for gliclazide as O/W microemulsion in the management of type 2 diabetes.