Nanoparticle-Mediated Nose-to-Brain Delivery for Ischemic Stroke Therapy: Preclinical Insights.

Ischemic stroke remains a major cause of mortality and long-term disability, yet current therapeutic strategies are largely limited to reperfusion approaches such as intravenous thrombolysis and thrombectomy, which are constrained by narrow treatment windows and the risk of complications. Moreover, the blood-brain barrier (BBB) severely restricts drug penetration into the injured brain, limiting the translation of promising neuroprotective agents into clinical success. Intranasal (IN) delivery has emerged as a compelling alternative route that bypasses the BBB and enables rapid access to the central nervous system through olfactory, trigeminal, and perivascular pathways. This narrative review highlights recent advances in preclinical research on IN therapeutics for ischemic stroke, ranging from small molecules and biologics to nucleic acids and cell-based therapies. Particular emphasis is placed on the application of nanotechnology, including extracellular vesicles, liposomes, and inorganic nanoparticles, which enhance drug stability, targeting, and bioavailability. Studies demonstrate that IN delivery of growth factors, cytokines, and engineered stem cells can promote neurogenesis, angiogenesis, white matter repair, and functional recovery, while nanocarriers further expand the therapeutic potential. Overall, intranasal delivery represents a promising and non-invasive strategy to overcome the limitations of conventional stroke therapies, offering new avenues for neuroprotection and regeneration that warrant further investigation toward clinical translation.