This study is an investigator-initiated Phase 1b clinical trial employing an open-label, non-randomized, dose-escalation design. The primary objective is to evaluate the safety and tolerability of the investigational intervention and to determine the recommended dose for subsequent clinical studies.

This study is an investigator-initiated, prospective, multicenter Phase Ib clinical trial designed to evaluate the safety, tolerability, and dose feasibility of anisodine hydrobromide administered in patients with acute ischemic stroke undergoing endovascular therapy. The trial adopts an open-label, non-randomized, dose-escalation design to identify the maximum tolerated dose (MTD) and to determine the recommended Phase II dose (RP2D).

Inclusion Criteria:

• Age 18 to 80 years.
• Imaging-confirmed anterior-circulation large-vessel occlusion involving the intracranial internal carotid artery, the middle cerebral artery M1 segment, or the proximal M2 segment or a dominant M2 branch. A dominant M2 branch was defined as an M2 branch supplying ≥50% of the middle cerebral artery territory.
• Eligible for and planned to undergo endovascular treatment (EVT) within 24 hours according to current clinical practice.
• National Institutes of Health Stroke Scale (NIHSS) score ≥6 at baseline.
• Alberta Stroke Program Early CT Score (ASPECTS) ≥6 on baseline noncontrast CT.
• Pre-stroke modified Rankin Scale (mRS) score of 0 to 1.
• Provision of written informed consent by the participant or the participant's legally authorized representative.

Exclusion Criteria:

• Evidence of intracranial hemorrhagic disease on head CT, including hemorrhagic stroke, epidural hematoma, subdural hematoma, intraventricular hemorrhage, or subarachnoid hemorrhage.
• History of congenital or acquired bleeding disorders, coagulation factor deficiency, thrombocytopenic disorders, or other clinically significant hemorrhagic conditions.
• Vascular anatomy expected to preclude successful endovascular treatment because of excessive tortuosity or other technical reasons.
• Known allergy to iodinated contrast agents.
• Pregnant or breastfeeding women, or women planning pregnancy during the study period or within 90 days after enrollment.
• Known hypersensitivity to anisodine hydrobromide or a history of severe intolerance after prior exposure.
• Presence of clinical conditions that may be worsened by anticholinergic drugs, including but not limited to angle-closure glaucoma, urinary retention or benign prostatic hyperplasia with dysuria, or paralytic ileus.
• Severe arrhythmia or hemodynamic instability, including but not limited to tachyarrhythmia requiring cardioversion, recurrent syncope due to arrhythmia, vasopressor-dependent hypotension, or persistent hypotension.
• Severe psychiatric disorder, dementia, or impaired consciousness that would preclude informed consent or protocol-required follow-up.
• Malignant tumor or other severe systemic disease with an expected survival of less than 90 days.
• Participation in another interventional clinical study within 30 days before enrollment, or current participation in another interventional clinical study.
• Any other condition that, in the investigator's judgment, makes the participant unsuitable for the study.

Related data will be shared if full study protocol and statistical analysis plan are provided with reasonable design.