Preparation and in vitro and in vivo Evaluation of Chitosan-Gliclazide Mucoadhesive Microparticles by an Emulsification-Desolvation-Crosslinking Technique

Introduction: Recently much emphasis is being laid on the development of microparticles because of their potential benefits such as increased bioavailability, reduced risk of systemic toxicity, reduced risk of local irritation and predictable gastric emptying. Objective: The objective of the present study is to prepare and evaluate mucoadhesive microparticles of chitosan-gliclazide for oral controlled release. Methods: A new method namely emulsification-desolvation-crosslinking was used for the preparation of chitosangliclazide microparticles and the microparticles were evaluated by in vitro and in vivo methods. Results: Spherical chitosan-gliclazide microparticles could be prepared by the emulsification-desolvation-crosslinking method. The method was reproducible with regard to size and size distribution of the microparticles. The chitosan-gliclazide microparticles exhibited good muoadhesive property. Gliclazide release from the chitosan microparticles was slow and extended over longer periods of time and depended on the proportion of core: coat. Gliclazide release from the chitosan microparticles was by diffusion mechanism. Microparticles (F3) prepared using a core: coat ratio of 8:2 gave slow and controlled release of gliclazide over 12 hr similar to that of commercial gliclazide SR tablets. In the in vivo evaluation, the gliclazide microparticles (F3) gave a slower reduction in serum glucose levels and the reduced glucose levels were sustained over longer periods of time. Conclusion: Microparticles (F3) are considered as a promising microparticulate drug delivery system for oral controlled release of gliclazide over 12 hr for b.i.d administration.