Development of Nitric Oxide-Donating Netarsudil Derivatives as a Synergistic Therapy for Glaucoma with Reduced Ocular Irritation

Based on the synergistic therapeutic effect of nitric oxide (NO) and Rho-associated protein kinase (ROCK) inhibitors on glaucoma, a series of NO-donating Netarsudil derivatives were designed, synthesized, and their activities in vitro and in vivo were evaluated. Among them, (<i>S</i>)-<b>10e</b> released an appropriate amount of NO in aqueous humor in vitro and displayed potent ROCK inhibition. Topical administration of (<i>S</i>)-<b>10e</b> significantly lowered intraocular pressure in an acute ocular hypertension rabbit model and protected retinal ganglion cells in a magnetic microbead occlusion mouse model. A metabolism investigation revealed that (<i>S</i>)-<b>10e</b> released <b>7a</b>, a metabolite after NO releasing, and <b>13</b>, an active metabolite of (<i>S</i>)-Netarsudil, in rabbit eyes. Notably, introducing an NO donor moiety attenuated ROCK inhibition-induced ocular irritation in an sGC-independent manner, suggesting that the attenuated conjunctival hyperemia effect of (<i>S</i>)-<b>10e</b> is related to the NO-induced protein S-nitrosation of phosphodiesterase 3A (PDE3A). Overall, (<i>S</i>)-<b>10e</b> is a promising candidate for glaucoma treatment.