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Discussion => Drug safety => Topic started by: sinister93 on March 05, 2013, 05:43 pm

Title: Chemistry question about Alprazolam and Ethanol
Post by: sinister93 on March 05, 2013, 05:43 pm
So I had a solution of 250 mg of pure alprazolam powder and I dissolved it in 200 ml of 190 proof everclear. I was kind of disappointed with the results, as there was way too much alcohol. So my question is: since ethanol has a boiling point of 78.37°C and alprazolam has a boiling point that is much higher (i don't know the exact temperature), but if I boil off some ethanol would it ruin the solution? Right now I have about 170 ml left of the solution, so i'm guessing there is roughly 220mg of alprazolam left. I want it to be like 2mg per .25 ml, how should I go about this?

I'm not expert chemist so
Any help is greatly appreciated, thanks!
Title: Re: Chemistry question about Alprazolam and Ethanol
Post by: Ben on March 06, 2013, 01:51 am
You are in luck. Alprazolam is a rather stable substance, and you can just boil off the excess solvent by heating the solution.

Since you used 95% alcohol to dissolve it, there would be no problem evaporating 80-90% or so of the volume away, the concentration will simply rise fivefold if you do.

Just don't boil it dry though - if the temperature shoots up over 200 degrees C you may get decomposition and ruin the alprazolam.

Also, don't over-concentrate it: alprazolam is not soluble in alcohol to enormous amounts. If you get to the point of 1 mg/ml, that should be very practical to handle, and i would not risk concentrating it any further by boiling solvent off using heat. You could use vacuum evaporation in a rotovap to get rid of the solvent completely, but i suppose you do not have a rotovap if you are asking.
Title: Re: Chemistry question about Alprazolam and Ethanol
Post by: nicetryguy on May 17, 2013, 10:39 pm
Sorry to bring up an old thread but what do you think the maxiumum solubility would be in 80 proof alcohol?
Title: Re: Chemistry question about Alprazolam and Ethanol
Post by: tree on May 18, 2013, 08:50 pm
1. look up the solubility for alprazolam in ethanol
2. multiply by 0.4 (80 proof)
3. ? ? ?
4. profit
Title: Re: Chemistry question about Alprazolam and Ethanol
Post by: Ben on May 20, 2013, 01:09 am
It's actually not that simple - 80 proof liquor has more water in it that it has alcohol, and you will run into problems with solubility. It also greatly depends on temperature, you can dissolve a lot more in warm 40% alcohol than you can in room temperature or cold alcohol.

I haven't calculated it though, but i think something like 80 proof  / 40% alcohol would hold 1 mg/ml at room temperature quite easily. If you  can, use something with a higher alcohol level though, it's much easier to evaporate alcohol off if you ever want to concentrate your solution or get a solid powder back.
Title: Re: Chemistry question about Alprazolam and Ethanol
Post by: tree on May 20, 2013, 09:24 am
It depends on temperature but solubility values are always for a given temperature, obviously. Even a tiny bit of another solvent can help something become soluble though, injectable diazepam is mostly water for example.
I agree that using something like everclear is a better option, but if only 80 proof alcohol is available it should work fine.
Title: Re: Chemistry question about Alprazolam and Ethanol
Post by: SealTeam6 on May 20, 2013, 09:27 am
I really want to hug this tree!