多肽和蛋白质类药物具有高效、低毒及药物间相互作用小的特性，使得它们越来越多地应用于临床。胃肠道在人体和外界之间形成了一个选择性屏障，允许营养物质、水等通过的同时阻止蛋白和多肽等大分子物质通过。因此，在过去的几十年中，许多科学家致力于口服纳米载体的研究。壳聚糖及其衍生物因具有黏膜黏附力、可逆地打开紧密连接及带有正电荷的特性，已被作为安全有效的肠道吸收促进剂。肠道主要通过跨细胞或细胞旁途径吸收物质，而壳聚糖可促进跨细胞及细胞旁途径的吸收。“,”Peptides and proteins featured with high efficiency,low toxicity and small drug interactions, are more and more applied in clinical practice.The gastrointestinal epithelium,forms the boundary between the body and external environment,effectively provides a selective permeable barrier that limits the perme-ation of peptide and protein,while allowing the appropriate absorption of nutrients and water .Over the past decades,many researchers have developed various nanoparticles for oral delivery systems.Chitosan (CS),a cationic polysaccharide,is widely regarded as a safe and efficient intestinal absorption enhancer of therapeutic macromolecules,owing to its inherent mucoadhesive feature and ability to modulate the integrity of epithelial tight junctions reversibly.The epithelial cells create this selective permeability by two pathways:the transcel-lular and the paracellular route.As an efficient absorption enhancer and drug carrier,CS increases both trans-cellular and paracellular transports of macromolecules across the intestinal epithelium .