Selumetinib (AZD6244) is a second-generation, orally available, potent and selective ATP non-competitive inhibitor of MEK 1/2. In direct assays, AZD6244 selectively inhibits purified active MEK1 and MEK2 AZD6244 demonstrated very effective anti-proliferation effects against several different cell lines with IC50 values ranging from a low of 3nM to < 1 µM depending upon the cell system used, and the compound inhibits basal and growth factor-stimulated phosphorylation of ERK1/ 2 with IC50 concentrations < 40 nM. AZD6244 has demonstrated potent dose-dependent antitumor activity against a panel of mouse xenograft models of colorectal, pancreatic, liver, skin, and lung cancer, and inhibition of tumor growth was found to correlate with the reduction of phospho-ERK1/2 levels in tumors. Alternative name: AZD-6244, ARRY-142886. Purity: ≥95% (HPLC). Solubility: Soluble in DMSO (92mg/ml) or ethanol (<1mg/ml). Long Term Storage: -20°C.