Use of insoluble biodegradable polymers in ophthalmic systems for the sustained of drugs

Biomaterials have made a great impact on medicine. However, numerous challenges remain. The eye presents special challenges for drug delivery in the treatment of various ocular diseases. Many of the conventional therapeutic modalities have not adequately solved these problems. Medicated biodegradable devices used for drug delivery may offer several advantages over conventional ocular drug delivery methods. In this review, we discuss firstly the different mechanisms of erosion leading to the dissolution of the polymeric drug delivery systems. The principal investigation using polymer exhibiting a biodegradation (erosion type III) characterized by the cleavage of the polymeric chain, and the formation of small molecules is presented. These biodegradable polymers discussed include poly(alkyl cyanoacrylates), poly(lactic acids), poly(glycolic acids) and their copolymers, polycaprolactones, polyanhydrides and poly(ortho esters). In the last part of this review the application of these biodegradable polymers to the treatment of glaucoma is presented.