Advances and applications of chitosan-based nanomaterials as oral delivery carriers: A review.

The oral drug administration was convenient and comfortable route for patients. Nevertheless, the oral uptake efficiency of many therapeutic agents was limited by physiological barriers of the gastrointestinal (GI) tract. This review summarized the challenges toward the oral delivery systems including instability and poor permeability in gastrointestinal environment. The transcellular and paracellular transport were main pathways of nanocarriers across intestinal epithelium. Chitosan is a nature and safe polymer that possesses the capacity of opening intercellular tight junctions of epithelium and excellent mucoadhesive property. Chitosan-based nanocarriers have recently attracted considerable attentions, aiming to overcome GI limitations and enhance drug absorption. Recently developed chitosan-based nanocarriers administered via oral route were highlighted for protecting drugs against degradation, releasing drugs in small intestine, enhancing drug uptake, thus improving oral bioavailability. Finally, various biotherapeutics including hydrophobic and hydrophilic drugs applied in chitosan-based nanovectors were also reviewed.