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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 6 of 6. This is the beginning of the thread.
Posted by lotus on August 28, 2003, at 23:21:10
I found this recently, check it out. http://triangle.bizjournals.com/triangle/stories/2003/07/07/daily10.html
Posted by CamW. on August 29, 2003, at 0:49:17
In reply to new Paxil alternative, posted by lotus on August 28, 2003, at 23:21:10
"The chemical difference between the two products is that the inactive part of the salt (mesylate or hydrochloride) is separated from the active paroxetine molecule in the gastrointestinal tract, ••leaving only the active paroxetine molecule to be absorbed into the bloodstream and provide the intended therapeutic effect••, the company said in a statement."
I haven't read anything that funny since I read somewhere that water has a memory. Most, if not all, solid drugs (eg powders, tablets) are salts. The powder (aka salt) occurs when an acid (HCl - hydrochloric acid) is added to a solution of a basic drug. The acid's H+ reacts with the base's OH- producing water and a salt is precipitated out (consisting of the basic drug bound to a chlorine ion).
This is not quite the whole story, but it shows that any drug salt (ie any drug in solid form) has to dissolve in the intestine; the solid drug has to dissociate into ions in the liquid (chyme) and then are absorbed.
I am not sure if paroxetine HCl is absorbed intact (I sincerely doubt it), but if it did it would probably have an easier time passing through the intestinal was into the bloodstream than the dissociate paroxetine mesylate, as large ionized molecules require active transport mechanisms and will (if at all) diffuse at a much slower rate (osmotically) than a non-ionic molecule.
•• In other words .... duh! I'm giving the writer of the article the benefit of the doubt. I think he added that paragraph as a "non-civil" jab at he company's rhetoric.
Just an observation, and thanks for bringing the article to our attention lotus. Just don't go running out to buy paroxetine mesylate for it's "unique" properties.
Cheers - Cam
Posted by Nohope on August 29, 2003, at 3:59:22
In reply to Re: new Paxil alternative » lotus, posted by CamW. on August 29, 2003, at 0:49:17
Hi Cam,
Was this a case of the Paxil manufacturer not covering all their bases with their patent?
Given your display of pharm prowess, I have a question for you: is Reboxetine just a modern tricyclic? Looking at a picture of the molecule reminds me of one. The tachycardia definitely reminds me of one.
Nohope
Posted by CamW. on September 3, 2003, at 1:13:39
In reply to Re: new Paxil alternative » CamW., posted by Nohope on August 29, 2003, at 3:59:22
Nohope - If you look at the three-dimensional configurations of many psychotropics in vivo, they resemble common antihistamines (eg. promethazine). It is just the side groups (-R) that make all the difference.
The traditional antipsychotics (eg. chlorpromazine [Largactil™], fluphenazine - [Modecate™], etc.), the tricyclic antidepressants (TCAs eg. imipramine - [Tofranil™], amitriptyline [Elavil™], etc.), olanzapine [Zyprexa™], clozapine (Clozaril™) and some other of the newer agents (can't remember which ones) have a modified promethazine shape.
I read about this in a really good autobiography by Jean Thuillier, "Ten Years That Changed The Face Of Mental Illness" (1981; English translation, 1999). It's the history of psychotropics by someone who was in the middle of the hunt for new "neuroleptics".
So, is reboxetine a TCA in a fancy dress? Probably! - Cam
Posted by Dr. Bob on September 3, 2003, at 21:10:16
In reply to Re: new Paxil alternative, posted by CamW. on September 3, 2003, at 1:13:39
> I read about this in a really good autobiography by Jean Thuillier, "Ten Years That Changed The Face Of Mental Illness" (1981; English translation, 1999).
I'd just like to plug the double double quotes feature at this site:
http://www.dr-bob.org/babble/faq.html#amazon
The first time anyone refers to a book without using this option, I post this to try to make sure he or she at least knows about it. It's just an option, though, and doesn't *have* to be used. If people *choose* not to use it, I'd be interested why not, but I'd like that redirected to Psycho-Babble Administration:
http://www.dr-bob.org/babble/admin/20020918/msgs/7717.html
Thanks!
Bob
Posted by Nohope on September 4, 2003, at 4:14:08
In reply to Re: new Paxil alternative, posted by CamW. on September 3, 2003, at 1:13:39
> Nohope - If you look at the three-dimensional configurations of many psychotropics in vivo, they resemble common antihistamines (eg. promethazine). It is just the side groups (-R) that make all the difference.
Does this mean that receptors for different neurotransmitters have very similar 'structures' - if that is a meaningful term? What are the implications for drug development? (does this make development easier or harder?)
Hopefully someone comes up with a different fundamental structure that forms the basis of a new family of medications - that is effective for us treatment resistant folk.
This is the end of the thread.
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