Stage 1-The trial will be conducted with 11 subjects participating in an open label design manner. Subjects with neurologic deficit of ≥4 point and ≤10 points on NIHSS score will be given SP-8203, 80mg/dose, a total of 6 times at intervals of 12 hours. For the first administration of SP-8203, it should be administered within 30 minutes from the initiation of rtPA administration via a vein route different from one via which rtPA is injected.