The effects of backing materials and multilayered systems on the characteristics of bioadhesive buccal patches.

The effects of backing materials (ethylcellulose, polyvinylpyrrolidone and cellulose acetate mixture, and poly(ethylene-co-vinyl acetate) on the characteristics (hydration and adhesion) of newly developed bioadhesive patches for controlled drug delivery via the buccal mucosa were investigated. It was found that the swelling profiles of buccal patches were changed dramatically by the species and amount of the backing materials, and those changes could alter the drug release profile. The drug release profiles of single-layered and multilayered buccal patches were significantly different. It was demonstrated that the multiple-layer device could be used to modify the drug release for obtaining the ideal clinical pharmacokinetic release profile.