Synthesis and in vitro study of dual acting hybrid compound for treating Glaucoma

Purpose: Glaucoma presents with high intraocular pressure (IOP) due to decreased aqueous humor outflow and impaired trabecular meshwork (TM). Increased IOP affects the optic nerve head leading to degeneration of retinal ganglion cells (RGC's). Currently many therapies aim to reduce IOP, however they do not address the damage done to the RGCs. Our goal is to find a multifunctional molecule that can lower IOP while also being neuroprotective. For this project, we planned to synthesize a series of compounds and evaluate their cellular activity in primary human TM cells. Methods: Compounds SA-2, PLGA encapsulated SA-2 nanoparticles (NP) and SA-24 were synthesized. Proton NMR and dynamic light scattering methods were used to determine structure and particle size. Greiss assay was used to assess total nitrite and reactive oxygen species (ROS) scavenging assay was performed following the manufacturer's protocol. Next, primary hTM-80 cells were seeded in 96 well plates to confluency, and exposed to tert-butyl hydrogen peroxide (TBHP, 300uM) for 15 min. followed by treatment with the compounds. The cell proliferation was measured using MTT assays (Promega). The experiments were done in quadruplicates. Results: SA-2, SA-2NP and SA-24 were equally effective in scavenging ROS at 250 µM and SA-2 provided highest amount of NO. Compound SA-2 (200uM) and SA-2NP (1%) significantly protect TBHP induced decreased cell proliferation. Conclusion: Compound SA-2 has both NO releasing and ROS scavenging activity. As expected, SA-2NP has slow release profile and better proliferative activity.