Development of sponge-like dressings for mucosal/transmucosal drug delivery into vaginal cavity.

The aim of the present work was the development of vaginal sponge-like dressings based on chitosan ascorbate (CS) and on hyaluronic acid sodium salt/lysine acetate (HAS) combination. Sponge-like dressings were prepared by freeze-drying and characterized for mechanical resistance and mucoadhesion. CS dressings show higher mechanical and mucoadhesion properties in comparison with HAS dressing. The enzymatic inhibition properties of the dressings were evaluated in vitro against carboxipeptidase A in view of their employment for vaginal delivery of peptidic drugs. All the dressings were able to inhibit carboxipeptidase activity; CS dressings, independently of polymer MW, completely inhibited enzyme activity. Release and penetration enhancement properties of the dressings loaded with a high molecular weight hydrophilic molecule, fluorescein isothiocyanate dextran (FD4), were assessed. CS dressings were able to prolong FD4 release. All the dressings showed penetration enhancement properties into pig vaginal mucosa although to a different extent: greater for dressings based on CS than for that containing HAS. Moreover, CS dressings demonstrated intrinsic antimicrobial properties. The suitability of sponge-like systems for the treatment of vaginal infections was assessed by loading the CS dressing characterized by the best mechanical and antimicrobial properties with an antibiotic drug (clyndamicin-2-phosphate) and by checking drug release.