Comment · Thu, June 19, 2014 · Ceretropic
The 'blood-brain barrier' vs. nootropics...why should they work?
Original post in this thread
bloodbrain1 · 1 points
I just read this article about the blood-brain barrier (BBB) in New Scientist and this phrase stood out: "The downside of this is that the BBB also completely blocks the vast majority of drugs. Exceptions include some classes of fat and lipid-soluble chemicals, but these aren't much help as such drugs penetrate every cell in the body – resulting in major side effects." How do we reconcile this with the observation that many nootropics and other drugs have effects on the brain?
http://www.newscientist.com/article/mg22229742.400-human-brains-ultimate-barrier-to-open-for-first-time.html#.U6HGt_ldXuQ?utm_source=NSNS&utm_medium=SOC&utm_campaign=twitter&cmpid=SOC%7CNSNS%7C2012-GLOBAL-twitter
What they were answering
Direct reply to the original post — see the thread post above.
u/MisterYouAreSoDumb · Ceretropic
Most nootropics are small molecules, and many have functional groups to allow them to either be more lipid soluble, which allows them to diffuse across the lipid membranes like the BBB, or atttach to carrier proteins that transport the molecule across the membranes. Take L-carnitine and ACLAR for example. The acetyl group makes it so that it can pass lipid bylayers a lot more efficiently. Then you have things like oxiracetam, which is just piracetam with a hydroxyl group. That changes the pharmacodynamics a lot.
That article is more dealing with very large drugs to treat diseases. Cancer drugs are especially hard to get into the brain, due to their size. That is why intranasal is being looked at for a lot of them.