Evaluation of intranasal delivery route of drug administration for brain targeting

•The two main pathways of intranasal drug absorption are the olfactory and trigeminal routes.•The intranasal drugs can bypass the blood-brain barrier and blood-CSF barrier.•There are in vitro, ex vivo and in vivo models for testing drug penetration by intranasal route.•The drug penetartion from nasal cavity can be enhanced by various formulations and devices.•Transporter modulation can also help in nasal delivery of their substrates.