How long can a syringe of trimix at room temperature be good before it spoils

[KaBoom]

If I take syringe out of a fridge/cooler, but dont use it until 3-4 hours later, is it still ok or does it lose its potency?

[ElbowRoom]

It will lose potency over days, not hours. You’re good to go.

[jwjwjw]

I've had a filled syringe out at room temperature for 24 hours and it worked fine.....

I'm not suggesting that but I think you will ok if this happens occasionally

[GoodWood]

The prostaglandin portion of Trimix is the component that is temperature sensitive.

But the extent id degradation at room temp is overstated.

As Elbowroom said, it takes place in days, not hours. There was a journal article listed in posts a while back that showed that over the course of days it lost around 10% of its potency. I think I experienced greater than 10% variation in the effect of my shots due to the day to day severity of my ED and and variation in how accurately I drew up the dose.

All of that to say, you should still get good effect with that shot. Have fun.

[GoodWood]

Here is a summary from ChatGPT with journal citations. I asked it to pull up full PDFs of the articles but due to copywrite issues it could only summarize. But if you really want to dig, the citations will let you track down the full articles.

PGE1 8-20% degradation between 5-10 days was the take away for me. And freezing does make it last longer but even in the fridge it’s stable a long time.

Quick summary (takeaway)
• Alprostadil (PGE₁) is the least stable component of Trimix/Bimix. Temperature and mixture components (especially papaverine) materially accelerate its loss. 
• Refrigeration (≈2–8 °C) slows degradation and is standard: many studies find acceptable stability for ~1 month refrigerated; some single-entity PGE₁ preparations have been stable up to 3–6 months when refrigerated under ideal conditions. 
• Freezing (−20 °C or colder) greatly improves long-term stability — studies report <5% loss over 6 months when frozen. 
• Room temperature (≈20–30 °C) causes substantially faster loss; substantial degradation can occur within days to weeks. One report shows ~8% loss in 5 days at room temp; other work shows PGE1 may lose 20–30% over weeks at room temperature depending on formulation. 
• Mixture effects: papaverine (and to a lesser extent phentolamine) accelerates PGE₁ degradation, with the greatest deterioration seen in the first 10 days after mixing. This is why PGE₁ is the limiting component for Trimix shelf life. 

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Key numeric findings (selected studies)
1. Soli et al., J Urol 1998 — chemical stability study of PGE₁ + papaverine + phentolamine:
• Papaverine and phentolamine remained ~96–103% of starting concentration for 60 days refrigerated.
• PGE₁ dropped to ~70–76% of starting concentration after 60 days in combinations; most rapid loss within first 10 days. 
2. Trissel (long-term Trimix stability), 2004 (pharmacy stability/bracketing):
• ~8% alprostadil loss in 5 days at room temp.
• Refrigeration: ~6% loss at 1 month, ~11% at 2 months in some conditions.
• Frozen (−20 °C and −70 °C): <5% loss at 6 months. 
3. Palmero et al., 2017 (PMC full text) — PGE₁ in 10% dextrose in polypropylene syringes:
• 1.5 and 15 μg/mL PGE₁ stable for 48 hours at 30 °C in UPL syringes — supports short-term room-temp use with appropriate packaging. 
4. Uebel et al., 2001:
• A sterile PGE₁ solution packed in insulin syringes: stability reported up to 24 weeks when stored at 5 °C (study conditions matter — presentation, diluent, preservatives, and aseptic technique). 
5. Patel et al., IJPC 2021 (Beyond-Use Date of Trimix) — reproducible bracketing study:
• Found that frozen storage supports long BUDs (months) while refrigeration supports shorter BUDs (~1 month); confirms PGE₁ is the limiting factor. (paper provides methods for bracketing and BUD assignment).