Selurampanel (Compound 1S) potently and dose-dependently antagonizes maximal electroshock seizure (MES)-induced generalized tonic-clonic seizures in mice with an ED50 value around 7 mg/kg after 1 h pre-treatment. In a study with a 3 mg/kg i.v. dose, a mouse plasma half-life of 3.3 h is determined, with a moderate volume of distribution (Vdss=1.3 L/kg) and a low clearance of 5.4 mL/min kg.