There have been lots of posts on this lately...refridgerating the drugs and the expirations. And I'll tell what I learned on Tri/Bi mix...assume similar for Quad, though I had not heard of this. I spoke directly to the pharmacist on these since I travel and had concerns.
Refridgeration: drug (at least the tri/bi mix) should not be exposed to heat over 86 degrees which is only about 16 degrees above normal room temp. So no hot cars, or next to heaters, etc. But room temp is actually fine. Refridgeration ensures that it is not exposed to higher temps. Won't lose potency from room temp.
Expiration: due to regulations...can't ensure sterility over long periods of time due to the way people use it. The longer the time from filling, the more incidences of contamination. So they put a 3 mo expiration on it for safety. The pharmacist told me if I do it right, the drug itself does not lose potency and should not become contaminated.
Needle Reuse: NEVER DO THIS. I saw it was mentioned as I scanned the thread of responses. HORRIBLE MEDICAL PRACTICE AND DOESN'T MAKE ANY SENSE. They syringes are dirt cheap compared to the drug...I just paid $10 for a box of 100 insulin syringes ($30 without insurance). THROW THEM OUT AFTER YOU USE THEM...OR IF YOU DROP ONE...OR ACCIDENTALLY TOUCH THE NEEDLE TO ANYTHING BUT THE INSIDE OF THE SYRINGE CAP.
Bi/Tri Mix: bimix has two meds, tri mix has three...logical. The difference is prostagladin (spelling?) which is the most potent ingredient, but is not always needed for some guys. It's also the ingredient that can cause aching. I have had some aching, but not too bad. Haven't tried the bi mix yet. My doctor goes right to the trimix since he's had the most success with his patients soon after surgery. I'm glad because the Levitra was not doing much or anything and I wasn't about to wait out months with no erections...I figured I had been through enough! I started it at 6 weeks.
Dosage: Trimix "recommended" dose is .2 CC which is 20 units on a .5 CC insulin syringe. I started with .04, because of what I read on here, which is 4 units and that lasted plenty long. Then I went to .02-.03 which works for me. Sometimes I don't get a full erection, but mostly it's more than enough, so really haven't increased dosage.
Hope that info helps.