Apparently the nasal-CNS connection can sometimes allow drugs administered as nasal drops or sprays to bypass the blood-brain barrier and access the brain directly.   In this case a Japanese team was able to get methotrexate (a non-BBB crossing antitumor agent) to the brains of rats by taking advantage of what they term “nose-brain direct transport.”

http://pubs.acs.org/doi/abs/10.1021/mp900275s