Improvement in the bioavailability of poorly absorbed glycyrrhizin via various non-vascular administration routes in XXXX .

@entity12504 @entity6212 @entity11950 @entity1372 @entity27145 @entity35 @entity1718
The purpose of this study was to examine the improvement of the bioavailability of @entity11950 (GL) via extra-vascular, i.e. oral, rectal, and nasal routes with or without the aid of an absorption enhancer in place of the vascular intravenous route in @entity35 . Pharmacokinetic behavior following administration via vascular routes, i.e. the intravenous and portal-venous routes was examined in @entity35 . The area under the plasma concentration-time curve (AUC) after administration of GL via the portal vein was decreased slightly, suggesting that the first elimination of GL in the liver may be one of the factors contributing to the low bioavailability after administration via the oral route. When GL was administered orally as a solution (30 mg/kg), the plasma concentration of GL was extremely low. However, after rectal or nasal administration of GL solution (30 mg/kg) with or without @entity27145 , the mean AUC value was remarkably increased compared with oral administration. In particular, the absolute bioavailability of GL after nasal administration was estimated to be approximately 20%, which was approximately 80-fold greater compared with after oral administration despite of the absence of an enhancer. Furthermore, the @entity1718 co-administered orally with GL produced an increase in GL absorption in the following order: @entity1372 caprate>sodiumlaurate> @entity6212 > @entity12504 . These results indicate that the rectum and nasal cavity are useful administration routes for systemic delivery of GL. It was also found that the @entity1718 were enhancers for the absorption of GL.
