Nanocarriers in Ocular Drug Delivery: An Update Review

Abstract

Controlled drug delivery to eye is one of the most challenging fields of pharmaceutical research. Low drug-contact time and poor ocular bioavailability due to drainage of solution, tear turnover and its dilution or lacrimation are the problems associated with conventional systems. In addition, anatomical barriers and physiological conditions of eye are also important parameters which control designing of drug delivery systems. Nanosized carriers like micro/nano-suspensions, liposome, niosome, dendrimer, nanoparticles, ocular inserts, implants, hydrogels and prodrug approaches have been developed for this purpose. These novel systems offer manifold advantages over conventional systems as they increase the efficiency of drug delivery by improving the release profile and also reduce drug toxicity. Conventional delivery systems get diluted with tear, washed away through the lacrimal gland and usually require administering at regular time intervals whereas nanocarriers release drug at constant rate for a prolonged period of time and thus enhance its absorption and site specific delivery. This review presents an overview of the various aspects of the ocular drug delivery, with special emphasis on nanocarrier based strategies, including structure of eye, its barriers, delivery routes and the challenges/limitations associated with development of novel nanocarriers. The recent progresses in therapy of ocular disease like gene therapy have also been included so that future options should also be considered from the delivery point of view. Recent progress in the delivery of proteins and peptides via ocular route has also been incorporated for reader benefit.

Safety evaluation of poly(lactic-co-glycolic acid)/poly(lactic-acid) microspheres through intravitreal injection in rabbits

“…These systems may also improve patient compliance. 10,11 The most popular dosing device is the microsphere, which is made up of poly(lactic-co-glycolic acid) (PLGA) and/or poly(lactic acid) (PLA). 12 This device has the inherent advantages of biodegradability and biocompatibility in nonocular tissues; it degrades into metabolic lactic and glycolic acids in vivo and eventually into water and carbon dioxide, which can be eliminated effectively from the body.…”

Solid lipid nanoparticles for ocular drug delivery

“…SLNs are mainly built from triglycerides in a specific orientation consisting of a polar core with polar heads facing towards the aqueous phase (Wadhwa et al, 2009). Many different lipids (triglycerides, hard fat types, partial glycerides, steroids, and waxes) and all classes of emulsifiers (ionic and non-ionic) have been used to prepare SLNs (Mehnert & Mäder, 2001).…”

Immunosuppressive Treatment of Non-infectious Uveitis: History and Current Choices

“…177 On the other hand, the superficial anatomic location, clear optical media for direct visualization and multiple compartments for drug retaining represent advantages of local drug delivery for this special organ. 178 However, like those newer biologic agents discussed in the previous section, this treatment modality is now under intense investigation with insufficient evidences to quality its general clinical applicability in the current stage.…”