Permeation of several drugs through keratinized epithelial-free membrane of hamster cheek pouch

The hamster cheek pouch mucosa was selected as a substitute for the human b uccal mucosa in an in vitro permeation study. Considering that a keratinize d layer is not present in the human buccal mucosa, keratinized epithelial-f ree hamster cheek pouch (KEF-membrane) was prepared by chemical splitting. To confirm the usefulness of the KEF-membrane, a permeation study was condu cted using several drugs with different lipophilicities. The permeability c oefficient of hydrophilic drugs through the KEF-membrane (P-kef) was signif icantly greater than that through a viable KEF-membrane (Pkef-viable), whic h was estimated by using the permeability coefficient of the viable full-th ickness membrane and that of the keratinized layer. On the other hand, the P-kef values of lipophilic drugs were comparable with the Pkef-viable value s. Furthermore, the ratio of these P values (Pkef/kef-viable) decreased wit h increasing lipophilicity of drugs. These findings indicate that the KEF-m embrane may be useful for buccal permeation studies of lipophilic drugs. (C ) 1999 Elsevier Science B.V. All rights reserved.