In vitro/in vivo studies on a buccal bioadhesive tablet formulation of carbamazepine

A buccoadhesive controlled-release system for delivery of carbamazepine (CB Z) was prepared by compression of hydroxypropyl methylcellulose (HPMC) and carbomer, incorporating a penetration enhancer, sodium glycodeoxycholate (G DC). The release behaviour of systems containing CBZ and various amounts of the two polymers with and without GDC was found to be non-Fickian. Formati on of an interpolymer complex between HPMC and carbomer was confirmed in ac idic medium by turbidity, viscosity and FT-IR measurements. Addition of the drug to the buccoadhesive formulation reduced the adhesion force significa ntly (p < 0.1), GDC did not have any effect on bioadhesion. Permeability of bovine buccal mucosa to CBZ was determined using Ussing diffusion chambers [I], In vivo interaction between the tablet and tissue was examined histol ogically as well as by scoring mucosal irritation. Histological changes obs erved in the buccal epithelium after 4 h contact with the tablets containin g GDC recovered completely within 24 h after removal. No measurable plasma level of CBZ was obtained either in the absence or presence of GDC.