ZM323881 hydrochloride is a potent and selective VEGFR2 inhibitor with an IC₅₀ of less than 2 nM. IC50 & Target: IC50: 2 nM (VEGFR2)^[1] In Vitro: ZM323881 is an anilinoquinazoline that potently inhibits VEGFR2 (KDR) tyrosine kinase activity anddemonstrates excellent selectivity versus other receptor tyrosine kinases, including PDGFRβ, FGFR1, EGFR and erbB2 (IC₅₀>50 μM). ZM323881 inhibits VEGF-A-induced endothelial cell proliferation(IC₅₀=8 nM) and VEGFR2 tyrosine phosphorylation^[1]. ZM323881 inhibits activation of VEGFR-2, but not of VEGFR-1, epidermal growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR), or hepatocyte growth factor (HGF) receptor. In HAECs, ZM323881 completely inhibits VEGF-induced ERK phosphorylation at 1 μM^[2]