Optimized PLGA Encapsulated SA-2 Nanosuspension Exhibits Sustained Intraocular Pressure Reduction in the Mouse Microbead Occlusion Model of Ocular Hypertension.

Elevated intraocular pressure (IOP) is implicated in the structural and functional damage to the retinal ganglion cells (RGCs) in primary open-angle glaucoma (POAG). Topical IOP lowering agents provide short-term relief, necessitating frequent dosing. Moreover, non-adherence to frequent eyedrops administration contributes significantly to visual field loss and worsens the disease outcome. We optimized the poly (lactic-co-glycolic acid) (PLGA) nanoparticles encapsulation of hybrid antioxidant-nitric oxide donor SA-2 (SA-2NP), investigated its bioavailability, duration of IOP lowering efficacy, and effects on retinal function in the microbead model of ocular hypertension (OHT). SA-2 was bioavailable in the anterior and posterior segments after 1, 8, and 24 h post-single topical eyedrop administration. SA-2NP significantly lowered IOP (∼25-34%) and preserved the RGC function after weekly eyedrop administration for 3 weeks in C57BL/6J mice. In conclusion, the optimized SA-2NP formulation demonstrated the desired bioavailability, ocular safety, and prolonged IOP-lowering efficacy in the mouse microbead occlusion model of OHT.