Cyclodextrin-based ocular drug delivery systems: A comprehensive review

Cyclodextrin (CD), a class of cyclic oligosaccharides with an external hydrophilic surface and a central hydrophobic cavity is recognized as a promising pharmaceutical excipient due to its unique ability to form inclusion complexes with small molecules and polymers. CD has excellent biocompatibility, safety, and stability, promoting the rapid development of various CD-based ocular drug delivery systems over the last two decades. The review elaborates on the recent research progress of CD-based ocular drug delivery systems, including drug/CD complexes, CD-based nanocarriers and microcarriers (e.g., nanoemulsions, nanoparticles, micelles, liposomes, nanosponges, microparticles, and microspheres), CD-based hydrogels (e.g., in situ hydrogels, supramolecular hydrogels, and soft contact lenses), and CD-based inserts. In addition, the review systemically summarizes the methods for ocular safety evaluation of CD-based ocular delivery systems, as well as the patents and clinical trials for CD-based ocular drug delivery systems.