Characterization of spray dried bioadhesive metformin microparticles for oromucosal administration.

Delivery of drugs into or via the oral cavity offers some distinct advantages due to the easy access to the oral mucosa, fast onset of action, and avoidance of hepatic and intestinal degradation mechanisms. To overcome the effective removal mechanisms existing in this area, bioadhesive drug delivery systems are considered a promising approach as they facilitate a close contact between the drug and the oral mucosa. In this study, bioadhesive chitosan-based microparticles of metformin hydrochloride were prepared by spray drying aqueous dispersions with different chitosan:metformin ratios and chitosan grades with increasing molecular weights.