Nanomedicine for oral delivery: Strategies to overcome the biological barriers

Summary

This review examines the biological barriers that limit oral drug bioavailability—stomach acid, the mucus layer, and the polarized intestinal epithelium—and evaluates nanoparticle strategies to overcome them. By tuning nanoparticle charge, size, and surface chemistry, and by adopting virus-inspired designs, researchers have improved payload protection, mucus penetration, and epithelial transport. The review highlights recent preclinical advances in oral nanomedicine for diabetes, cancer, inflammatory bowel disease, and colorectal cancer, emphasizing that effective oral delivery requires coordinated design across all barriers rather than optimization of a single feature. Continued progress could expand the range of orally available therapies, though clinical translation remains to be demonstrated.