Formulation of unidirectional release buccal patches of carbamazepine and study of permeation through porcine buccal mucosa.

OBJECTIVE: To achieve transbuccal release of carbamazepine by loading in unidirectional release mucoadhesive buccal patches. METHODS: Buccal patches of carbamazepine with unidirectional drug release were prepared using hydroxypropyl methyl cellulose, polyvinyl alcohol, polyvinyl pyrrolidone and ethyl cellulose by solvent casting method. Water impermeable backing layer (Pidilite® Biaxially-oriented polypropylene film) of patches provided unidirectional drug release. They were evaluated for thickness, mass uniformity, surface pH and folding endurance. Six formulations FA2, FA8, FA10, FB1, FB14 and FB16 (folding endurance above 250) were evaluated further for swelling studies, ex vivo mucoadhesive strength, ex vivo mucoadhesion time, In vitro drug release, ex vivo permeation, accelerated stability studies and FTIR and XRD spectral studies. RESULTS: The ex vivo mucoadhesion time of patches ranged between 109 min (FA10) to 126 min (FB14). The ex vivo mucoadhesive force was in the range of 0.278 to 0.479 kg/m/s. The In vitro drug release studies revealed that formulation FA8 released 84% and FB16 released 99.01% of drug in 140 min. CONCLUSIONS: The prepared unidirectional buccal patches of carbamazepine provided a maximum drug release within specified mucoadhesion period and it indicates a potential alternative drug delivery system for systemic delivery of carbamazepine.