Fig. 1

Schematic representation of key aspects of intranasal delivery of neuroprotection compounds to the brain. TBI is difficult to treat as most therapeutic agents (98%) cannot reach in the brain, mainly due to the selective permeability of the blood–brain barrier (BBB). The olfactory and trigeminal nerves can serve as direct nose-to-brain routes that bypass the BBB that can impede absorption of most CNS targeted compounds, resulting in higher bioavailability. In addition, compared to traditional routes, the nasal administration of drugs can direct the rapid CNS absorption to brain tissues, thereby circumventing the hepatic first-pass metabolism and gastric degradation and allowing fast onset of pharmacological action