Feasibility of Lipid Nanoparticles for Ocular Delivery of Anti-Inflammatory Drugs

Due to the multiple barriers imposed by the eye against the penetration of drugs, the ocular delivery and targeting are considered difficult to achieve. A major challenge in ocular drug therapy is to improve the poor bioavailability of topically applied ophthalmic drugs by overcoming the severe constraints imposed by the eye on drug absorption. One of the promising strategies nowadays is the use of colloidal carrier systems characterized by a submicron-meter size. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) represent promising alternatives to conventional and very popular ocular carrier systems, such as the nanoemulsions, liposomes, and polymeric nanoparticles. Nevertheless, taking into account the characteristics of the eye, morphometrical properties of the colloidal systems (e.g., average particle size and polydispersion) may represent a limiting factor for topical application without induced corneal irritation, being responsible for the selected system. This review article focuses on the application of lipid nanoparticles (SLN, NLC) as carriers for both non-steroidal and steroidal anti-inflammatory drugs for the treatment of ocular inflammatory disorders. Major benefits, as well as shortcomings, of ocular inflammation conditions are described, in particular upon management of inflammation induced by ocular surgery (e.g., cataracts, refractive surgery). Particular emphasis is given to the clinical choices currently available, while examining the most recent drugs that have been approved.