Transcytosis in drug absorption and distribution

Abstract

The term transcytosis designates the vesicular transcellular transport of molecules from one side of a polarized epithelial or endothelial cell to the other. It is a key process for the absorption and/or distribution of large molecules, e.g., macromolecules, or, in some cases, more complex entities, e.g., nanoscale particles/constructs.Epithelial cell layers line the outer surfaces of organs throughout the body, as well as the inner surfaces of cavities in many internal organs. They act as selective barriers, regulating the transference of molecules (and, at times, supramolecular structures) in and out of organs. Endothelial cell layers, which line the interior surface of the blood vessels, accomplish an equivalent function in separating the vascular space from the extravascular tissues. They are thus critical barriers in the processes of drug absorption and distribution for systemic...