Valproic acid magnesium (Magnesium valproate) is an orally active HDAC inhibitor, with IC50 in the range of 0.5 and 2 mM. Valproic acid magnesium inhibits HDAC1 (IC50, 400 µM), and induces proteasomal degradation of HDAC2. Valproic acid magnesium activates Notch1 signaling and inhibits proliferation in small cell lung cancer (SCLC) cells. Valproic acid magnesium is used in the epilepsy, bipolar disorder, metabolic disease, HIV infection and prevention of migraine headaches[1][2][3][4][5][6][7].