"The cerebellar uptake of IN delivered neurotherapeutics is found to peak at 12h rapidly declining by 24h. IP delivery does not exhibit peak cerebellar uptake at any particular time point, rather it is observed to be at the same level at all time-points. Cerebellar uptake of neurotherapeutics after IN delivery is ~5 ± 2 times greater than that after IP delivery"
In other words intranasal delivery results in far higher drug levels in the cerebellum compared to intraperitoneal injection, which is the usual method for delivering drugs to lab animals.
From the study: Brain Uptake of Neurotherapeutics after Intranasal versus Intraperitoneal Delivery in Mice
The question from here is which therapies are formulated for intranasal delivery. Perillyl alcohol and chlorotoxin (scorpion venom) are taken this way, though neither of them are easy to access. As we've discussed recently there are curcumin nasal sprays on the market, though I haven't seen any clinical research published with them.
Let's make this the "intranasal therapy" thread.