Visualization of the penetrative and mucoadhesive properties of chitosan and chitosan-coated liposomes through the rat intestine.

The objectives of this study were to observe the penetrative and mucoadhesive behavior of polymer-coated liposomes into the intestinal mucosa of rats. Chitosan (CS) and negatively charged liposomes were chosen as model polymer-coated liposomes. In order to observe their behavior, chitosan was labeled with Fluorescence Isothiocyanate (FITC) via chemical reaction at the isothiocyanate group of FITC and the primary amino group of chitosan; the liposomes (Lips) were marked by incorporation of DiI into the liposomal formulation. FITC-labeled chitosan (FITC-CS), Non-Lips, and FITC-labeled CS-coated Liposomes (FITC-CS-Lips) were intragastrically administered into male Wistar rats, and the behavior of the molecules was subsequently visualized by CLSM (Confocal Laser Scanning Microscopy). The results demonstrated that the chitosan molecules themselves, as well as the liposomes, could penetrate across the intestinal mucosa. Moreover, the CLSM images demonstrated a lack of separation of the chitosan molecules from the surface of the liposomes after the administration of chitosan-coated liposomes.