Long Term Glaucoma Drug Delivery Using a Topically Retained Gel/Microsphere Eye Drop

Area of Science:

• Ophthalmology
• Biomaterials Science
• Drug Delivery Systems

Background:

• Glaucoma is a leading cause of irreversible blindness.
• Current glaucoma treatments often require frequent administration, leading to poor patient compliance.
• There is a need for sustained-release drug delivery systems for ophthalmic conditions.

Purpose of the Study:

• To characterize and evaluate the efficacy of a novel, long-term, non-invasive gel/microsphere (GMS) eye drop for glaucoma treatment.
• To assess the drug release properties and in vivo performance of the GMS system.

Main Methods:

• Developed a thermoresponsive hydrogel carrier with drug-loaded polymer microspheres.
• Quantified in vitro brimonidine release and gel properties.
• Administered a single brimonidine-loaded GMS drop to normotensive rabbits and monitored intraocular pressure (IOP) for 28 days.

Main Results:

• In vitro studies characterized brimonidine release and gel properties.
• A single GMS drop in rabbits resulted in IOP reduction comparable to twice-daily standard brimonidine drops over 28 days.
• The GMS drops remained in the ocular fornix throughout the study duration.

Conclusions:

• The GMS eye drop demonstrated sustained in vivo efficacy for 28 days after a single administration.
• This novel drug delivery system shows potential for reduced systemic absorption compared to conventional eye drops.
• This represents a pioneering long-term, drug-releasing depot administered as a conventional eye drop.