Hyaluronic acid-based nanoparticles to deliver drugs to the ocular posterior segment

Ocular posterior segment diseases such as uveitis, X-linked juvenile retinoschisis, or age-related macular degeneration usually result in progressive and irreversible vision loss. Although intravitreal injection is the main way to deliver drugs to the posterior eye, it still has shortcomings as an invasive operation. Nanocontrolled drug delivery technology is a promising option to avoid frequent injections. Due to the particularity of the human intraocular structure, drugs have unique pharmacokinetic characteristics in the eye. Various nanoparticles have been successfully investigated in experimental studies for vitreous injection, with advantages and drawbacks. Here, we introduce an ideal nanopolymer modifier to build nanodelivery systems in vitreous cavities. Hyaluronic acid (HA) is a natural polysaccharide with a broad molecular weight range, negatively charged surface, ligand-receptor binding capabilities, and hyaluronidase breakdown capability. Advances in CD44 receptor targeting for HA-based nanoparticles can improve mobility and penetration in the vitreous and retina, stabilize the nanoparticles, and regulate drug release. This review summarizes the intravitreal administration of nanoplatforms based on HA and the benefits of HA in drug delivery systems.