Stimulants PG vs. Distilled Water for 2-Week Amphetamine Volumetric Solution?

[Deleted member 594230]

I’m planning to prepare a two-week supply (120 mg total) of dextroamphetamine for oral dosing at 5 mg/mL. I’ve read the basics, but I’m still deciding on the best solvent for this short-term (14-day) use and have a few specific questions.

1. 100% Propylene Glycol (PG)
2. 100% Distilled Water
3. Distilled Water with 0.9% Benzyl Alcohol (as a preservative)

For a solution that will be used up within 14 days (stored in an amber glass vial), is 100% PG the one to choose or pure distilled water? I know PG is antimicrobial, but is the contamination risk with pure water over two weeks that high, or is it more of a "better safe than sorry" rule? Would the BA/water mix be the best in terms of solubility and sterility, or overkill?

I have a sealed, unopened 30 mL bottle of USP-grade Benzyl Alcohol. It's been sitting at room temperature in my closet for about a year (still sealed). If I open it to make a 0.9% BA/water solution:

1. Is it still considered "sterile" and good to use after being sealed for that long?
2. More importantly, once I open it, what's its realistic shelf life? The info I find says "use within 28 days once opened," but that seems aimed at medical settings. If I keep it tightly closed in a dark cupboard and only use a few mL at a time for future batches, can I realistically use the same bottle over several months/years for multiple 2-week preparations? Or does it genuinely degrade or become unsafe (not just less sterile) after a month once the seal is broken?

I don't want to open and waste a whole bottle if it truly goes "bad" in 28 days. But if I can use it safely for many small batches over a longer period, it might be worth opening. I mean 30ml BA would last me around 5 years, but I am ok with it if i can use it for a year or so safely, then throw away the rest.

Thanks in advance

Edit: I also have sterile PTFE hydrophilic .22um 25mm syringe filters (if i should draw water or bac into a clean sterile vial)

 

[yeee707]

Hello was reading your post and can you maybe walk me through your process please ?

 

[Skorpio]

I’m planning to prepare a two-week supply (120 mg total) of dextroamphetamine for oral dosing at 5 mg/mL. I’ve read the basics, but I’m still deciding on the best solvent for this short-term (14-day) use and have a few specific questions.

1. 100% Propylene Glycol (PG)
2. 100% Distilled Water
3. Distilled Water with 0.9% Benzyl Alcohol (as a preservative)

For a solution that will be used up within 14 days (stored in an amber glass vial), is 100% PG the one to choose or pure distilled water? I know PG is antimicrobial, but is the contamination risk with pure water over two weeks that high, or is it more of a "better safe than sorry" rule? Would the BA/water mix be the best in terms of solubility and sterility, or overkill?

I have a sealed, unopened 30 mL bottle of USP-grade Benzyl Alcohol. It's been sitting at room temperature in my closet for about a year (still sealed). If I open it to make a 0.9% BA/water solution:

1. Is it still considered "sterile" and good to use after being sealed for that long?
2. More importantly, once I open it, what's its realistic shelf life? The info I find says "use within 28 days once opened," but that seems aimed at medical settings. If I keep it tightly closed in a dark cupboard and only use a few mL at a time for future batches, can I realistically use the same bottle over several months/years for multiple 2-week preparations? Or does it genuinely degrade or become unsafe (not just less sterile) after a month once the seal is broken?

I don't want to open and waste a whole bottle if it truly goes "bad" in 28 days. But if I can use it safely for many small batches over a longer period, it might be worth opening. I mean 30ml BA would last me around 5 years, but I am ok with it if i can use it for a year or so safely, then throw away the rest.

Thanks in advance

Edit: I also have sterile PTFE hydrophilic .22um 25mm syringe filters (if i should draw water or bac into a clean sterile vial)

Is this all for oral/rectal use? If so, water on its own should be fine (and you could store it in a fridge to be doubly sure). Micron filtering the water only solution could be another way to feel more confident.

For long term storage or nasal/iv/im use I would add the benzyl alcohol and then micron filter the whole solution.

Though making a master stock (10-100x concentrated), freezing it, and diluting
that to make new short term stocks is a good approach if only doing oral dosing (or boofing).

I can’t think why the benzyl alcohol would go off in 28 days. It isn’t very hospitable to microbes (hence why 0.9% is sufficient to be bacteriostatic), and I don’t think it’s super chemically reactive (if it were to oxidize, you would smell almonds due to the presence of benzaldehyde, which is used in almond/cherry flavoring.

The propylene glycol would also be a decent option if you are sticking to oral use.

Your approach seems to be amply thorough. 14 days is not a huge amount of time. If you see the solution becoming cloudy, or building up pressure that is a sign of microbial life, but again, starting with sterile water, you are unlikely to have growth occur that quickly in a fortnight.

 

[Deleted member 594230]

Is this all for oral/rectal use? If so, water on its own should be fine (and you could store it in a fridge to be doubly sure). Micron filtering the water only solution could be another way to feel more confident.

For long term storage or nasal/iv/im use I would add the benzyl alcohol and then micron filter the whole solution.

Though making a master stock (10-100x concentrated), freezing it, and diluting
that to make new short term stocks is a good approach if only doing oral dosing (or boofing).

I can’t think why the benzyl alcohol would go off in 28 days. It isn’t very hospitable to microbes (hence why 0.9% is sufficient to be bacteriostatic), and I don’t think it’s super chemically reactive (if it were to oxidize, you would smell almonds due to the presence of benzaldehyde, which is used in almond/cherry flavoring.

The propylene glycol would also be a decent option if you are sticking to oral use.

Your approach seems to be amply thorough. 14 days is not a huge amount of time. If you see the solution becoming cloudy, or building up pressure that is a sign of microbial life, but again, starting with sterile water, you are unlikely to have growth occur that quickly in a fortnight.

Yes all for oral use. So you think no need for benzyl alcohol? I would buy sterile water for injection which is pyrogen free so no need to filter, better than distilled water. Its my first time mixing powders, so I dont know much. But if you think just sterile water is fine for 2 weeks, then I wont bother with benzyl alc.

 

[Skorpio]

Yes all for oral use. So you think no need for benzyl alcohol? I would buy sterile water for injection which is pyrogen free so no need to filter, better than distilled water. Its my first time mixing powders, so I dont know much. But if you think just sterile water is fine for 2 weeks, then I wont bother with benzyl alc.

Sterile water should be fine for two weeks.

 

[Deleted member 594230]

Sterile water should be fine for two weeks.

Thanks

 

[Deleted member 594230]

Sterile water should be fine for two weeks.

Also is there a point in using sterile water if i will take it oral? Does it have any benefit over distilled water?

 

[Skorpio]

Also is there a point in using sterile water if i will take it oral? Does it have any benefit over distilled water?

Not really. I’ve used tap water boiled in a tea kettle for similar solutions kept for ~3 weeks.

I would personally not use unboiled tap water, but I’m kind of picky about aseptic technique.