Considerations for Polymers Used in Ocular Drug Delivery

Abstract

PurposeAge-related eye diseases are becoming more prevalent. A notable increase has been seen in the most common causes including glaucoma, age-related macular degeneration (AMD), and cataract. Current clinical treatments vary from tissue replacement with polymers to topical eye drops and intravitreal injections. Research and development efforts have increased using polymers for sustained release to the eye to overcome treatment challenges, showing promise in improving drug release and delivery, patient experience, and treatment compliance. Polymers provide unique properties that allow for specific engineered devices to provide improved treatment options. Recent work has shown the utilization of synthetic and biopolymer derived biomaterials in various forms, with this review containing a focus on polymers Food and Drug Administration (FDA) approved for ocular use.MethodsThis provides an overview of some prevalent synthetic polymers and biopolymers used in ocular delivery and their benefits, brief discussion of the various types and synthesis methods used, and administration techniques. Polymers approved by the FDA for different applications in the eye are listed and compared to new polymers being explored in the literature. This article summarizes research findings using polymers for ocular drug delivery from various stages: laboratory, preclinical studies, clinical trials, and currently approved. This review also focuses on some of the challenges to bringing these new innovations to the clinic, including limited selection of approved polymers.ResultsPolymers help improve drug delivery by increasing solubility, controlling pharmacokinetics, and extending release. Several polymer classes including synthetic, biopolymer, and combinations were discussed along with the benefits and challenges of each class. The ways both polymer synthesis and processing techniques can influence drug release in the eye were discussed.ConclusionThe use of biomaterials, specifically polymers, is a well-studied field for drug delivery, and polymers have been used as implants in the eye for over 75 years. Promising new ocular drug delivery systems are emerging using polymers an innovative option for treating ocular diseases because of their tunable properties. This review touches on important considerations and challenges of using polymers for sustained ocular drug delivery with the goal translating research to the clinic.

Drug-Loaded Polymeric Particulated Systems for Ophthalmic Drugs Release

“…Depending on the carrier properties and the physical–chemical characteristics of the drugs, they can reach only external layers (cornea, conjunctiva or sclera), internal (aqueous humor, iris, ciliary body, vitreous humor or retina) or both after topical instillation or intraocular administration [ 36 , 37 ]. However, only 1–7% of the administered drugs can reach the aqueous humor level because of tear distribution and conjunctival and cornea barriers [ 38 , 39 ]. In the present study, polymeric particulate systems are studied in terms of efficiency as carriers of drugs with applicability in ophthalmology and other medical fields (dexamethasone/pilocarpine/bevacizumab).…”

Fluorescent Nanosystems for Drug Tracking and Theranostics: Recent Applications in the Ocular Field

“…Currently, the most widely studied nanosystems are used in the treatment of anterior eye diseases such as cataracts [ 25 ], glaucoma [ 26 ], dry eye syndrome [ 27 ], keratitis [ 28 ], conjunctivitis [ 29 ] and uveitis [ 30 ], but also posterior eye diseases such as retinitis [ 31 ], macular degeneration [ 32 ], endophthalmitis [ 33 ] and ocular tumors [ 34 ]. Suitable drug nanocarriers possess a mean size in the nanometric range (around 200 nm) and are classified according to their structural composition and the materials used, which must be biodegradable and biocompatible [ 35 , 36 ]. Many reviews focus on the development of nanosystems designed for ocular delivery, but none on the ophthalmic use of fluorescent nanocarriers.…”

Glaucoma Treatment and Hydrogel: Current Insights and State of the Art

“…Hydrogels are a network of biologic and synthetic hydrophilic polymers able to absorb aqueous fluids. The extensive array of customizability and the high hydrophilicity render hydrogel the ideal compound for ophthalmic applications, ranging from vitreous substitutes to drug delivery [ 21 ]. Several authors proposed hydrogel as a drug carrier, incorporated with other polymers, to treat glaucoma.…”