Intravitreal nanoparticles for retinal delivery.

Intravitreal injection is one of the major administration routes for the treatment of posterior ocular diseases. Intravitreal therapeutics usually suffer from unsatisfactory efficacy owing to fast clearance from the vitreous humour and insufficient distribution into the retina. Engineered nanoparticles have been applied for specific tissue targeting over the past decades. In this review, we summarize the most recent research utilizing intravitreal nanoparticles to deliver therapeutics to the retina. Herein, the achievement made in preclinical research and challenges remaining in the field are highlighted. Parameters including size, charge, stability and choice of modified ligand on intraocular distribution and transport are also systematically discussed based on a proposed pharmacokinetic model. We provide insights for rational design principles for intravitreal nanoparticles for targeted retinal delivery.