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 buccal mucosa in an in vitro permeation study. Considering that a keratinized layer is not present in the human buccal mucosa, keratinized epithelial-free hamster cheek pouch (KEF-membrane) was prepared by chemical splitting. To confirm the usefulness of the KEF-membrane, a permeation study was conducted using several drugs with different lipophilicities. The permeability coefficient of hydrophilic drugs through the KEF-membrane (P-kef) was significantly greater than that through a viable KEF-membrane (Pkef-viable), which was estimated by using the permeability coefficient of the viable full-thickness membrane and that of the keratinized layer. On the other hand, the P-kef values of lipophilic drugs were comparable with the Pkef-viable values. Furthermore, the ratio of these P values (Pkef/kef-viable) decreased with increasing lipophilicity of drugs. These findings indicate that the KEF-membrane may be useful for buccal permeation studies of lipophilic drugs. (C) 1999 Elsevier Science B.V. All rights reserved.