Prior to sacrifice at 1 h, 6h, or 16h, blood samples were collected in Vacutainer and serum tubes; (BD, Franklin Lakes, NJ). Serum samples were sent to the Massachusetts General Hospital Core Lab facility to measure the levels of circulating VPA in the blood. At 1h, VPA in circulation from a 450 mg/kg dose was significantly higher than that from a 300 mg/kg dose (p<0.05). At 6h, the level of VPA in circulation from a 450 mg/kg dose was significantly higher than the 300 mg/kg and the 400 mg/kg dose (p<0.05). By 16h, any significant differences in circulating VPA levels have disappeared. * denotes a significant difference (p<0.05).