Chapter 4 - Polymeric micelles as a novel carrier for ocular drug delivery

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Abstract Topical drug delivery is considered as the first option in the treatment of eye diseases. But, the unique anatomical structure and physiological functions of the eye restricts entry of drugs to target sites in the eye. In addition, dynamic and static ocular barriers also diminish drug absorption through intra ocular tissues. Thereby, topical administration of drugs via conventional dosage forms mostly result in low ocular drug bioavailability as well as the necessity of frequent dosing and low patient compliance. As another approach, intravitreal injections are applied to deliver drugs into the posterior segment of the eye, but this application causes serious side effects such as retinal detachment or hemorrhage in the eye. Periocular injections also have side effects such as high intraocular pressure, cataract development, and corneal decompensation. Development of novel topical carriers to deliver drugs to targeted eye segments would satisfy this unmet medical need. Thus delivery of drugs at therapeutical doses to the eye is an urgent challenge especially for the treatment of posterior segment diseases. In order to overcome this issue, nanotechnology-based drug carriers have been widely investigated over the past few decades. Polymeric micelles are colloidal carriers which assemblies of nanoscale size. They are composed of amphiphilic block polymers and characterized by core–shell morphology formed through the self-association of hydrophilic and hydrophobic block copolymers in water. Micelles can increase the aqueous solubility of hydrophobic/lipophilic compounds. Their small sizes also provide enhanced permeability and retention and can be used to target inflamed areas. Thus polymeric micelles have received much attention due to their potential for the enhancement of topical bioavailability and improvement of ocular permeability of drugs. This chapter discusses the recent research findings and applications of polymeric micelles as ocular drug delivery systems for the treatment of eye diseases.