Lymphatic delivery in 'rectal drug delivery systems'

This article summarizes the structure of the mammalian gastrointestinal vascular system, the fundamentals of lymphatic transport of drugs from the enteral route and the development of a lymphotropic drug delivery system in a rat model. According to the considerable difference in the permeability of lymphatic and blood capillary walls, we can expect molecular weight-dependent lymphotropic characteristics of the drugs. Therefore, macromolecularization using ionic binding or an inclusion compound is a suitable strategy for development of a lymphotropic drug delivery system. However, due to the poor permeation through the gastrointestinal mucosa of such a macromolecular complex, the aid of a safe absorption enhancer such as lipid-surfactant mixed micelles is indispensable. (C) 1997 Elsevier Science B.V.