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Biotech / Medical : VD's Model Portfolio & Discussion Thread -- Ignore unavailable to you. Want to Upgrade?

To: nigel bates who wrote (5594)	9/8/1998 3:21:00 AM
From: SnowShredder	Respond to of 9719

The effects of the blood brain barrier are very interesting (I'm no expert). From what I understand, measuring the hydrophobicity of a drug is an indicator on how well it will work in the brain. An example is take the structures of cocaine vs. heroin (I think this is the one) they are exactly the same except that heroin has 2 methyl (CH3) groups replacing 2 hydroxyl groups (OH). And heroin is much more potent than cocaine. Is heroin more potent because it can cross the blood brain barrier faster than cocaine? or is it because it can cross the blood brain barrier and then get trapped on the other side? I don't know the answer, but if anyone does please let me know. Thanks. Best of Luck, Where'd He Go?

To: nigel bates who wrote (5594)	9/8/1998 12:13:00 PM
From: Biomaven	Respond to of 9719

Nigel, I know of a couple of existing drugs that are delivered as intra-nasal sprays. There's a nasal calcitonin spray for osteoporosis, and a nasal DHE [di-hydro-ergotamine (sp?)] spray for migraines. Some company (I think IPIC) is working on an intra-nasal lidocaine/dextromethorphan spray, also for migraines. I don't know if these are getting through the blood/brain barrier or not. I know calcitonin is not absorbed well orally, although DLVRY now has an novel oral version as well as an oral insulin in trials. Peter

To: nigel bates who wrote (5594)	9/9/1998 3:19:00 AM
From: Rocketman	Read Replies (1) \| Respond to of 9719

I'm not so sure this is that relevant to blood/brain barrier crossing. However through nasal delivery, you can avoid the evils of delivering via the digestive system (acidic conditions with digestive enzymes and hot peppers, pizza and beer attacking the drugs), the problems of getting into blood with intramuscular injections, the difficulty of having patients do their own intravenous injections, the hassle with injections in general and still get drugs into the blood stream fairly regularly and reliably. When I was in college in the early 80's they tried intranasal ADH (anti-diuretic hormone) on me when the docs were suspicious that I was deficient in it (I drink a LOT of water). Had a little curved tube that I'd suck up about 5 microliters into, and then stick one end in my nose and blow into the other. Only took it a few times as it made me sick as a dog, couldn't eat or drink, felt like I had a rubber stomach and gave me a booming headache. The conclusion was that I must not be deficient and that I liked to drink lots of water (medicine by trial and error, kind of like auto mechanics). It was a great way to deliver a sensitive hormone that couldn't take the digestive tract and required just a very small dosage - convenient and painless. Getting the hang of blowing in the tube while inhaling with your nose was a bit tricky but not insurmountable. It is not new as a delivery means as snuff sniffers have known for centuries. Nasal delivery has been around a long time. It is just getting better at getting more difficult molecules into the blood stream thus opening up previously unviable therapies. Rman