Evaluation of insulin permeation across the rabbit nasal mucosa using the ussing chamber system

Permeation of insulin across the nasal mucosa, a desirable absorption site for peptide and protein drugs to avoid their first-pass effect and gastrointestinal degradation, excised from rabbits and the effect of bile salts as permeation enhancers on it were evaluted by using Ussing chamber system. Insulin was degraded in this system, and the degradation in the mucosal side was slightly sooner than that in the serosal side. Every bile salt (0.5%) used in this study reduced transmucosal electrical resistance (Rm) and enhanced insulin permeation. The degradation of insulin in the mucosal side was inhibited by addition of a bile salt, sodium taurodihydrofusidate. These results suggest that the Ussing chamber system becomes a useful tool to evaluate the enzymatic barrir function of nasal mucosa.