SU5408 (VEGFR2 Kinase Inhibitor I) is a potent and cell-permeable inhibitor of VEGFR2 kinase with an IC₅₀ of 70 nM. IC50 & Target: IC50: 70 nM (VEGFR2)^[1] In Vitro: 3-Substituted indolin-2-ones have been designed and synthesized as a novel class of tyrosine kinase inhibitors which exhibit selectivity toward different receptor tyrosine kinases (RTKs). These compounds have been evaluated for their relative inhibitory properties against a panel of RTKs in intact cells. SU5408 (VEGFR2 Kinase Inhibitor I) is found to be the most potent and selective VEGFR2 inhibitor among the compounds. SU5408 (VEGFR2 Kinase Inhibitor I) shows little or no effect against receptors for platelet-derived growth factor, epidermal growth factor, or insulin-like growth factor (IC₅₀>100 µM)^[1].