MUCOADHESIVE POLYMERS FOR THE BUCCAL DELIVERY OF PEPTIDES, STRUCTURE ADHESIVENESS RELATIONSHIPS

Buccal delivery of small peptides, such as hypothalamic peptides and vasopresin analogues, requires delivery systems which are capable of protecting the peptide against degradation by, e.g., peptidases in the oral fluid and which at the same time ensure intimate contact between the peptide and the mucous epithelium and optimal transmucosal absorption. Bio- or muco-adhesiue polymers seem favourable candidates for this purpose. As a basis for our studies, it was assumed that bioadhesiveness requires at least two properties: (1) optimal polarity is needed to make sure the polymer is sufficiently "wetted" by the mucus; (2) optimal fluidity permits the mutual adsorption and interpenetration of polymer and mucus to take place within a reasonable period of time. This study pertains to acrylic polymer films, designed for buccal drug delivery and in which said requirements have been met either through mixing poly(butyl acrylate) and polyacrylic acid, or through copolymerization of butyl acrylate and acrylic acid. In both cases satisfactory muco-adhesiveness was found within a range of compositions where both the surface polarity and the fluidity of the polymer film were optimized. Furthermore, results of recent in vitro itstudies on the adhesive properties of freshly excised porcine oral mucosa will be discussed. © 1990.