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Benzodiazepines salt?

Beerman

Bluelighter
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Jan 25, 2010
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Hi all, I've done sometimes conversion of a drug wich is in salt form (example: cocaine hcl) and turn it to his free-base form (to smoke for example)

My question is: knowing that all benzos are amines (or that's what I think :S), and so, freebased drugs, why them can't be turned to the salt form using an acid, like switching freebase heroin (for example) to HCL heroin to get it water soluble?? Are the benzos unstables on acid? benzos are not bases? XD

This is maybe a stupid question but I don't ever know why benzos can't be "changed" to a salt form.

Thanx, Beerman.
 
Bronsted: weak base reacts with strong acid. The traditional benzo skeleton is very weakly basic, with basicity at the imine. This forms an unstable salt that readily undergoes double hydrolysis. The first hydrolysis, at the imine, is reversible; the second, at the amide, isn't (and so the structure decomposes to an aminobenzophenone and a substituted glycine).

The imidazo- and triazolo- benzos (like midazolam and triazolam) have at least 1 additional basic nitrogen and lack the amide, so they only undergo the first (reversible) hydrolysis. In aqueous solution they stay hydrolyzed, but at pH 7.4 (blood) they deprotonate and regain their original structure.

Also, notice that chlorazepate is sold as a dipotassium salt, and this is possible because it has the carboxylic moiety. In the stomach it decarboxylates and at intestinal or physiologic pH it becomes nordiazepam.

Also, any benzo with an amino (not amido!) moiety is protonated there when treated with an equimolar amount of strong acid. This is because the amino moiety is more basic than the imino moiety.

There are other exceptions, but the principle is the same.
 
Can triazolam really be converted into a salt? What i'm thinking is making a solution of Halcion tablets with a bit of citric acid to yield triazolam citrate for IV use (to be used after micron filtering).
 
Can triazolam really be converted into a salt? What i'm thinking is making a solution of Halcion tablets with a bit of citric acid to yield triazolam citrate for IV use (to be used after micron filtering).

Correct me if I'm wrong, but I think you need a strong acid. Upjohn used to make triazolam hydrochloride, which is definitely water-soluble.

You probably have to get all the shit off of the pill before making the salt.
 
Correct me if I'm wrong, but I think you need a strong acid.

I think you're wrong... at least, midazolam is in tartrate form in the pills I usually get, so I don't see why triazolam couldn't be made into a salt using relatively weak acids.
 
^You're right about midazolam. The available salts are the hydrochloride, lactate, saccharate, maleate, fumarate and tartrate.

Triazolam is another story. There's history in the literature of the hydrochloride (no longer commercially available AFAIK). That's it. Searching for "triazolam tartrate" or "triazolam citrate" or others yields material like:

. . . Dr. Yi, noted for his BUY TRIAZOLAM CITRATE in developing columnar mesophases of BUY VIAGRA BUY TRIAZOLAM CITRATE NO PRESCRIPTION has been appointed head of the Ministry of . . .

The same holds for another triazole, alprazolam. Upjohn used to sell the hydrochloride, but I can't find history of any other salt formulations.

Not insignificant is the fact that the imidazole ring is 1000 times more basic than the 1,2,4-triazole ring.



This is OT, but has me salivating:
NSFW:
imgsrv.fcgi

AcelRx Pharmaceuticals Reports Positive Results from a Clinical Trial of Sublingual Sufentanil/Triazolam NanoTab Combination (ARX-03) in Treating Procedural Pain and Anxiety

REDWOOD CITY, Calif., January 12, 2009 /PRNewswire/ -- AcelRx Pharmaceuticals, Inc., an emerging specialty pharmaceutical company focused on the treatment of intermittent and acute medical conditions with an initial emphasis on pain management, today announced positive results from a Phase 1 clinical study evaluating the safety, tolerability and efficacy of the company's proprietary sublingual sufentanil (opioid) and triazolam (benzodiazepine) NanoTab(TM) combination product candidate (ARX-03). The product is designed to address the current unmet need for a non-invasive product to provide sedation and analgesia for an increasing number of office-based procedures.

The study demonstrated that administration of ARX-03 resulted in a statistically significant increase in sedation levels for the 10mcg sufentanil/200mcg triazolam dosage strength in both a younger cohort (age range 18-60 years; p=0.009) and an older cohort (age range of 61-80 years; p=0.003) as compared to sublingual sufentanil alone. These data were collected using the Richmond Agitation-Sedation Scale (RASS), a validated and objective test for assessment of sedation levels. The average onset of sedation was 20-30 minutes for the higher dosage strength in each study cohort.

Additionally, sublingual administration of the sufentanil/triazolam combination was found to be safe and well tolerated. Based on these positive results, AcelRx intends to further advance clinical development of ARX-03 in 2009.

"We believe the results of this trial are particularly valuable as they offer clinical evidence well beyond what is expected from a typical Phase 1 study. Not only have we shown ARX-03 to be safe and well-tolerated, we have also demonstrated significant pharmacodynamic findings with a randomized, double-blind design that spanned different age groups and multiple dosage levels," said Pamela Palmer, M.D., Ph.D., chief medical officer of AcelRx Pharmaceuticals.

This 24-patient two-cohort, five-arm crossover study included administration of open-label oral triazolam and IV sufentanil on days one and two followed by a double-blinded, randomized dosing of a sublingual NanoTab(TM) containing high-dose sufentanil/triazolam, low-dose sufentanil/triazolam and 10mcg sufentanil only on days three to five.

ARX-03 is designed to provide analgesia, anxiolysis and mild sedation without requiring the presence of an anesthesiologist, in a safe, simple, non-invasive form for use in procedural settings. The product is based on the company's proprietary NanoTab(TM) dosage form, which enables delivery of the sufentanil/triazolam combination by the non-invasive oral transmucosal (sublingual) route, resulting in high drug bioavailability but significantly lower and safer peak plasma levels than IV.

"The very positive data generated from this study validates the clinical applicability of this product concept from both a safety and efficacy point of view, and further underscores the commitment of AcelRx to advance the clinical development of this program," said Thomas A. Schreck, chairman and chief executive officer of AcelRx Pharmaceuticals. "The positive findings that AcelRx recently announced regarding our lead product candidate, ARX-01, combined with the impressive data from this ARX-03 study demonstrate the breadth and value of the AcelRx pipeline and strongly positions the company for future success."

Procedural pain and anxiety in the doctor's office and clinic setting represents a significant unmet medical need for patients and healthcare providers. Most physician's offices and clinics cannot provide appropriate staffing for IV sedation, often resulting in patients experiencing high levels of pain and anxiety. Ideal treatment of procedural pain and anxiety minimizes patient awareness and discomfort, while maintaining patient safety. A preferred product candidate for treatment of procedural pain and anxiety should possess sedative, analgesic and amnestic properties, be safe, easy to use and administered via a non-invasive route, and have a rapid onset and a sufficient duration of action which allows for rapid recovery and discharge. AcelRx's novel ARX-03 sublingual NanoTab(TM) is designed to satisfy these criteria.

AcelRx is preparing to initiate a Phase 2a clinical trial to further evaluate the safety and efficacy of ARX-F03 for treatment of procedural pain and anxiety.
 
What about the possibility of turning etizolam into a salt? Sorry to bump this old thread, but what you said is still relevant.

I don't see an amide (not a Chemist :) ) but dunno about the basic nitrogen atom.


The molecule!
NSFW:
Etizolam.svg
 
There ain't no basic nitrogens there. Etizolam Is basically xanax is disguise and that doesn't form salts either.

Wait... I'm comfused... A few posts back seep said alprazolam used to be available from Upjohn as the HCl salt, now you're saying it doesn't form salts. If it can be done with alprazolam, why shouldn't it work with etizolam? The relevant site is unchanged between the two... What am I missing?
 
The only benzo that's a salt (that I'm aware of) is Chlordiazepoxide Hydrochloride. The Methylated group at the top would make freebase chlordiazepoxide's bioavailability too low. Otherwise take a look at all the other benzo's.

Xanax (Alprazolam)
Ativan (Lorazepam)
Valium (Diazepam)
Klonopin (Clonazepam)
Restoril (Temazepam)
Halcion (Trizolam)

Do you see 'Hydrochloride' or 'Sulfate' on the end of those? Exactly, you don't. Why? Because all that's inside of the pill is freebase Lorazepam, or freebase Alprazolam or what have you. If they were 'salted' they would have the name of the reagent at the end of the drug's name.

Example: Paroxetine Hydrochloride
 
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The Methylated group at the top would make freebase chlordiazepoxide's bioavailability too low.

Not quite... it's an issue of water solubility and not much else. Freebase CDX would be absorbed just fine. (it's very lipophilic)
 
Not quite... it's an issue of water solubility and not much else. Freebase CDX would be absorbed just fine. (it's very lipophilic)

I figured that was wrong tbh. But I came up with a possible explanation off the top of my head.

You're better at chemistry than me ;)
 
See, that's what I'd always thought. I did some searching, and it seems that seep had mispoken, since, like you said, I cannot find any solid sources that say alprazolam has ever been available as the HCl salt, since it is not possible to prepare it that way. I wonder where seep got that idea from...
 
The Methylated group at the top would make freebase chlordiazepoxide's bioavailability too low
What if you smoked it? ;)

See, that's what I'd always thought. I did some searching, and it seems that seep had mispoken, since, like you said, I cannot find any solid sources that say alprazolam has ever been available as the HCl salt, since it is not possible to prepare it that way. I wonder where seep got that idea from...


I would say it is fallacious to think just because A hasn't been B before that is proof A will never be B.

Your search should have been as to whether it is possible.

Not trying to be an assole, but maybe I am.
 
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