• Select Your Topic Then Scroll Down
    Alcohol Bupe Benzos
    Cocaine Heroin Opioids
    RCs Stimulants Misc
    Harm Reduction All Topics Gabapentinoids
    Tired of your habit? Struggling to cope?
    Want to regain control or get sober?
    Visit our Recovery Support Forums

Benzos Does propylene glycol spoil?

ryohazuki

Greenlighter
Joined
Jul 7, 2013
Messages
20
I've got a gram of pure xanax powder and was hoping to dissolve all of it straight away in 500ml of propylene glycol and store it in a mason jar. However my friend warned me that once the PG is exposed to air it may eventually spoil the solution, and that I should either look into it or dissolve smaller amounts of powder at a time when need be.

Well, I've been trying to look into it and haven't had much luck. Does anyone know if PG can spoil the drug if left on a shelf for too long? And if so, for how long is it good?
 
Has to contain:

Water
Propylene glycol
Succinic acid

If you can't find succinic acid you can replace it with acetic acid because it has a similar pKa. In 500mL it would give you 2mg/mL which is a little too much, I would make it in 1L. Bottle has to be brown, air tight and away from heat.
 
Using 500mL of PG seems like a waste since you can achieve same results with a much more diluted solution but if you do use water it has to be de-ionized with a resistance above 15MΩ. Grocery store acetic acid doesn't qualify either. You need pure stuff. 100% acetic acid 5mL diluted into 400mL of 15MΩ de-ionized water with 95mL of pure propylene glycol.
 
I don't think I'll use water. So you're saying acetic/succinic acid preserves the solution from spoiling?

I've dissolved xanax with only using 100% propylene glycol at 2mg/ml without a problem before. I'm not really concerned about "wasting" any PG, considering how cheap it is. I just don't want the solution to spoil.

Thanks for the replies.
 
I don't think I'll use water. So you're saying acetic/succinic acid preserves the solution from spoiling?

I've dissolved xanax with only using 100% propylene glycol at 2mg/ml without a problem before. I'm not really concerned about "wasting" any PG, considering how cheap it is. I just don't want the solution to spoil.

Thanks for the replies.

Propylene glycol is a reducing agent. When I look at Xanax molecule I am clueless to what could get reduced, maybe other chemists got a different opinion. It could work with only propylene glycol but the thing is that, comercially, these solutions contain some type of weak acid. So, this is the time when you go like, I don't know why they do it but it's standard procedure so doing like them is better even if I don't understand why momentarily.

The explanation to why they use an acid can be as dumb as "so that they don't snort it". I don't know. lol Could be anything.
 
Well my biggest concern was whether if propylene glycol would spoil the xanax if both were mixed and kept in a jar for too long..
 
Propylene glycol is a reducing agent.

is it now? never seen it used for that purpose.

the reason that pharma companies add acids is twofold.
1. pH control (some drugs don't dissolve in basic sol'n)
2. some acids are bacteriostatic or antibacterial. (benzoic acid notably)

the propylene glycol on its own (even at 30% in water) is enough to kill microorganisms, and PG is regularly used in not only antifreeze but also as a thickening agent for e.g. cough syrups.

tl;dr: PG won't go bad if you keep it concentrated.
 
is it now? never seen it used for that purpose.

the reason that pharma companies add acids is twofold.
1. pH control (some drugs don't dissolve in basic sol'n)
2. some acids are bacteriostatic or antibacterial. (benzoic acid notably)

the propylene glycol on its own (even at 30% in water) is enough to kill microorganisms, and PG is regularly used in not only antifreeze but also as a thickening agent for e.g. cough syrups.

tl;dr: PG won't go bad if you keep it concentrated.

Ya I used it to reduce HAuCl4 into nanoparticles. It's weak, not like NaBH4 or LiAlH4 but it does the job. Thanks for the info on the acid.

Sekio brings a good point also, OP careful, you might not be able to disolve so much alprazolam to get 2mg/mL. You might not be able to go above 1mg/mL make sure you check that before you wet the powder. It sucks to see your powder fall at the bottom...lol
 
Thanks guys. I was able to dissolve 2mg per ml no problem. Adding some heat helps it disperse ten fold, and I would say is absolutely necessary even if it looks completely clear.

I decided to just store most of the solution in a mason jar in a cool dark place. Hopefully all goes well.
 
Top