Abstract

The oral route is the preferred mode of administration, however the poor intestinal absorption of many bioactive compounds limit their efficacy. Several strategies have been developed to overcome the low oral bioavailability of bioactive compounds. Nanocarriers present a unique opportunity to overcome this limitation due to their diverse bioactive carriage potential, surface functionality and design flexibility. Despite these favorable characteristics, the oral delivery of nanocarriers faces several challenges which are discussed in this review. The review addresses the different mechanisms of transport across the intestinal epithelium. In addition, we will comment on the various methods and models for evaluating the intestinal permeability, with a critical discussion of the uniformity of these models in investigating the oral bioavailability of nanocarrier systems. Finally, we will discuss some of the recently developed nanocarriers for oral delivery of bioactives that show promising results.

Keywords: Caco-2, Intestinal epithelium models, M cells, nanocarriers, oral delivery, oral insulin, oral vaccine, targeted delivery, transcytosis.