Improved oral bioavailability of glyburide by a self-nanoemulsifying drug delivery system

Aim: The present study aimed at the development and characterisation of self-nanoemulsifying drug delivery system (SNEDDS) to improve the oral bioavailability of poorly soluble glyburide. Methods: The solubility of glyburide was determined in various oils, surfactants and co-surfactants which were grouped into two different combinations to construct ternary phase diagrams. The formulations were evaluated for emulsification time, droplet size, zetapotential, electrical conductivity and stability of nanoemulsions. Result: The optimised SNEDDS loading with 5 mg/g glyburide comprised 55% Cremophor((R)) RH 40, 15% propanediol and 30% Miglyol((R)) 812, which rapidly formed fine oil-in-water nanoemulsions with 46 +/- 4 nm particle size. Compared with the commercial micronised tablets (Glynase((R)) PresTab((R))), enhanced in vitro release profiles of SNEDDS were observed, resulting in the 1.5-fold increase of AUC following oral administration of SNEDDS in fasting beagle dogs. Conclusions: These results indicated that SNEDDS is a promising drug delivery system for increasing the oral bioavailability of glyburide.