Formulation development and characterization of microemulsion for topical delivery of Glipizide

In the present work glipizide based microemulsion was developed and its usefulness as topical drug carrier system for the non-insulin dependent diabetes mellitus (NIDDM) was investigated. Microemulsion was prepared by water titration method using oleic acid as oil phase, tween-80 as surfactant and propylene glycol as co-surfactant. Menthol as a permeation enhancer was added to a final drug-loaded microemulsion formulation at the level of 1% w/w. Microemulsions were characterized for pseudo-ternary phase diagrams, pH, viscosity, droplet size, in vitro release profile, ex-vivo diffusion study, irritancy tests, stability and in vivo evaluation. The optimized microemulsion formulation was found to be o/w type emulsion by pseudo ternary phase diagram and having mean particle size of 138±4.5 nm. The results indicated that the developed microemulsion systems, especially ME-3, may be promising vehicles for the transdermal delivery of glipizide. In vivo studies were carried out on wistar rats and the samples were analyzed for glucose content by Accu-check blood glucose meter. Inclusion complex showed significant blood glucose reduction as compared to drug alone. Microemulsion system provides viscous consistency for the topical application, which delivered the drug in sustained or controlled manner and prolonged delivery as compared to conventional dosage form.