Sustained drug delivery platforms – A new era for glaucoma treatment

Glaucoma is a leading cause of blindness worldwide. Treatment typically consists of the chronic administration of topical eye drops. However, fluctuations in intraocular pressure, local and systemic side effects, and low patient compliance have prompted the development of various sustained drug delivery platforms, both extraocular and intraocular, over the last decade. Some are currently undergoing advanced clinical trials. Extraocular platforms include wearable ocular surface devices (such as ocular insert rings, topical ocular drug delivery devices, gel-forming eye drops, collagen shields, and contact lenses), punctal plugs (such as the OTX-TP and Latanoprost punctal plug delivery system), and subconjunctival injections (such as the Eye-D VS-101, POLAT-001, GB-6249-103, IBI-60089, and dorzolamide-loaded polymer microparticles). Intraocular platforms include mainly intracameral implants (such as the Bimatoprost SR, ENV515 Travoprost XR, iDose, OTX-TIC, PA5108, and DE-117-loaded PLC), although other devices are drawing attention as potential treatment alternatives (such as intravitreal nanosponges and supraciliary implants). The purpose of this review is to describe these emerging sustained drug delivery systems for the treatment of glaucoma and ocular hypertension.