SDZ 220-581 is an orally active, potent, competitive NMDA receptor antagonist with pK_i value of 7.7^[1]. IC50 & Target: pKi: 7.7 (NMDA receptor)^[1] In Vivo: SDZ 220-581 (3.2-32 mg/kg; oral administration; for 24 hours; male OF-l mice) treatment dose-dependently protects mice against maximal electroshock seizures (MES). The time-course of protection by SDZ 220-581 is characterized by a rapid onset and long duration of action^[1].