The effect of physical barriers and properties on the oral absorption of particulates

This paper provides an in-depth review of the biological, immunological, an d physicochemical barriers to the oral absorption of microparticles. The ro les of the mucus and mucosal cell layers are discussed along with technolog ies and strategies that may be used to improve uptake, including attempts t o determine the mechanisms of microparticulate uptake into enterocytes and membranous epithelial (M) cells. Considerations unique to the absorption of microparticles, such as particle size, surface characteristics, cell surfa ce interactions, and the driving force for absorption of microparticles, ar e also addressed. Although the extent of absorption of microparticles is se verely limited, this review provides insight into potential methods and tec hnologies that have been and could be used to improve the oral absorption o f microparticles. (C) 1998 Published by Elsevier Science B.V. All rights re served.