PREPARATION AND IN VITRO ASSESSMENT OF VARIOUS MUCOSA-ADHESIVE FILMS FOR BUCCAL DELIVERY

The aim of this study was to examine various polymers considered to have mucosa-adhesive properties for the preparation of buccal-adhesive films and their in vitro evaluation. A number of materials, such as cellulose derivatives, carbopols and natural polymers, were employed for the preparation of buccal-adhesive films. Aqueous solutions containing the mucosa-adhesive polymer and a plasticizer were prepared and used to prepare films by the "solvent cast" method. Prepared films were then evaluated in terms of their physical appearance and film forming ability, in vitro mucosa-adhesive strength and duration of mucosa-adhesion. Results showed that among the various materials examined, sodium carboxymethyl cellulose (CMC) formed very flexible films with the greatest mucosa-adhesive strength. Further studies showed that the combination of carbopols and CMC, along with glycerin as the plasticizer, resulted in the formation of films with desirable appearance and a relatively stronger mucosa-adhesive strength than films containing CMC alone. In vitro studies showed that films containing carbopol 934P, CMC and glycerin gave the greatest mucosa-adhesive strength and longer mucosa-adhesion. In conclusion, this formulation is proposed as a good base for the preparation of buccal-adhesive films and patches. Furthermore, it is suggested that in the development of buccal-adhesive drug delivery systems, and in particular films and patches, duration of mucosa-adhesion determined by in vitro experiments is a critical factor in the selection of the ultimate formulation.