(rac)-AR-13503 ((rac)-AR-13324 M1 metabolite) is the isoform of AR-13503. AR-13503 a ROCK/PKC inhibitor, inhibiting angiogenesis and enhancing retinal pigment epithelium (RPE) permeability. AR-13503 also inhibits the formation of aberrant neovascularization (NV) in oxygen-induced retinopathy (OIR) model in mice.