Preparation of mucoadhesive buccal patches of carvedilol and evaluation for in-vitro drug permeation through porcine buccal membrane

This investigation aimed at developing and evaluating mucoadhesive buccal patches of carvedilol. Permeation of carvedilol was calculated in vitro using porcine buccal membrane. Buccal formulations were developed by solvent-casting technique using chitosan as mucoadhesive polymer. The patches were evaluated for in vitro release, moisture absorption and mechanical properties. The optimized formulation, based on in vitro release and moisture absorption studies, was subjected for bioadhesion studies using porcine buccal membrane. In vitro flux of carvedilol was calculated to be 2.25 +/- 0.11 mu g h(-1) cm(-2) and buccal absorption was also demonstrated in vivo in rabbits. In vitro drug release and moisture absorbed was governed by chitosan content. The mechanical properties, tensile strength (12.85 +/- 4.5 kg mm(-2) for formulation P-3) and elongation at break reveal that the formulations were found to be strong but not brittle. The peak detachment force and work of adhesion for formulation P-3 were 0.72 +/- 0.18 N and 0.19 +/- 0.21 mJ, respectively. The results indicate that suitable bioadhesive buccal patches of carvedilol with desired permeability and suitable mechanical properties could be prepared.