EEL SKIN AS A MODEL SUBSTRATE FOR MUCOADHESION STUDIES

The inherent fragility and instability of mammalian excised mucosal ti ssues constitutes a serious problem in ex vivo mucoadhesion studies. T he present investigation was undertaken to assess the validity of eel (Anguilla anguilla) skin as a model mucous substrate. Eel skin was cha racterized physically (thickness, water and lipid content), histologic ally (light microscopy) and physico-chemically (differential scanning calorimetry). Its characteristics had many points in common with those of rabbit and human oral mucosae. A series of polymer-based formulati ons, both semisolid (hydrogels) and solid (matrices), were tested for mucoadhesion on eel skin using a tensile apparatus, providing data on the work of adhesion, W, to the substrate. A dispersion of hog gastric mucin layered on filter paper was used as a reference mucous surface. In these preliminary tests eel skin compared favorably with the refer ence substrate, and proved a robust and stable substrate for mucoadhes ion studies.