Purity ~99%. MS-275 is a synthetic benzamide derivative that inhibited partially purified human histone deacetylase (HDA) with an IC50 of 2uM and induced hyperacetylation of nuclear histones in tumor cell lines. MS-275 inhibited the proliferation of various human tumor cell lines such as A2780, Calu-3, HL-60, and K562 (IC50 values were 0.0415uM, 0.195uM, 0.212uM, and 0.589uM, respectively). MS-275 also inhibited the growth of human tumor xenografts in nude mouse. Solubility: Soluble in DMSO at 25mg/ml with slight warming; very poorly soluble in ethanol and water; maximum solubility in plain water is estimated to be about 10-20uM. buffers, serum, or other additives may increase or decrease the aqueous solubility.