Efficacy and Safety Study of Neu2000KWL for Acute Ischemic Stroke Patients Within 6 Hours of Onset

Inclusion Criteria: 1. patients aged between 35 and 75 years; 2. acute ischemic stroke patients in internal carotid artery system within 6 hours of onset; 3. patients with NIHSS scores of 4 to 22 and limb weakness including motor arm or motor leg score ≥2 of NIHSS; 4. patients within 6 hours of onset or the last time known to be symptom free (within 6 hours of the start of sleep for ischemic stroke patients with onset during sleep), and who receive a CT test before the clinical study; 5. Informed consent should be signed from the patient or patient's legally authorized representative; 6. patients with premorbid mRS score of 0\~1; 7. patients with no history of myocardial infarction within last 3 months; 8. patients with no heart, liver, kidney and lung function deficit; 9. patients with no hemorrhagic diseases within last 3 months; 10. patients with no haematological diseases. Exclusion Criteria: 1. Any contraindication to CT and MRI (e.g., metal implants such as pacemakers, claustrophobia); 2. Stroke caused by posterior circulation ischemia, or transient ischemic attack (TIA); 3. Acute intracranial hemorrhage, intracranial neoplasm, cobweb hemorrhage, cerebritis or other non-acute ischemic stroke and cerebral arteriovenous malformation; 4. Endovascular treatment within 6 hours of onset, such as mechanical embolectomy, stent angioplasty or arteriovenous bridge treatment; 5. Pregnant or lactating women. Note: the pregnancy test of fertile women must be negative before randomization into groups, and female patients must take appropriate contraceptive methods at least for 3 weeks prior to the clinical study and over the next 7 days following the last injection of test drugs; 6. Pre-existing medical, neurologic, or psychiatric diseases that would confound the neurologic, functional, or imaging evaluations, such as persistent deficit from previous ischemic stroke; 7. Malignant tumor or other critical disease; 8. Patients with a history of epilepsy or undergoing seizure on onset of the ischemic stroke 9. A history of intracranial hemorrhage; 10. Patients with low blood pressure, or showing blood pressure lower than 90/60mmHg in three consecutive times after admission; 11. A history of severe injury and surgical operation within the last 3 months; 12. Consciousness disorder as defined as "NIHSS Ia score ≥2 "; 13. Complete atrioventricular block bradycardia; 14. Cardiac function rating above II level according to the New York heart association (NYHA) grade of cardiac function, history of congestive heart failure (CHF); 15. With primary liver and kidney disease, AST or ALT 2 times greater than upper normal limit, serum creatinine \>2.0 mg/dL or \>176.8 µmol/L; 16. International normalized ratio (INR) \> 1.7 or current use of oral anticoagulants, except aspirin, clopidogrel, subcutaneous heparin or warfarin; 17. With bleeding tendency disease (such as hemophilia), partial thromboplastin time (PTT) \> 3 ×the upper limit of normal; 18. A history of, or known current problems with, drug or alcohol abuse; 19. A irritability experience of the study drugs or drugs with similar chemical structures; 20. Participation in other clinical trials or studies before this study within the last 3 months; 21. Researchers consider that patients don't suit for the study. 22. Hepatitis B and C, HIV-positive patients Imaging exclusion criteria: 1. patients with high density lesions associated with haemorrhage on CT scan after admission; 2. patients with significant lower density lesions of 1/3 middle cerebral artery on CT scan after admission; 3. patients with intracranial parenchymal tumors on CT scan after admission.