抄録
Various biological membranes (barriers) at the sites of drug administration have increased in interest in drug delivery. Epithelial barriers such as gastrointestinal, dermal, nasal, and pulmonary barrier are reviewed at a cellular, biochemical, and anatomical level. Several factors, enzymatic metabolism and membrane permeability, are concerned in drug delivery, Penetration enhancers, for example, act on the various biological barriers at a different extent. Thus absorption enhancers are overviewed, and their enhancing mechanism is presented and discussed from the point of drug delivery system.
