[Question] reconstitution — what am I missing here
reconstitution — what am I missing here. If this has been answered properly somewhere, link me and I will delete. The dead space question sent me down a rabbit hole for a week. It is a fraction of a unit and it is the same every draw. Spent 14 weeks confused about this until somebody drew the table for me. 10mg, 3mL,…
bacteriostatic water has the preservative, sterile water does not
Agreed on the swirl. There is no reason to shake it and a good reason not to.
Agreed on the swirl.
Adding one thing — put the date on the label too. Concentration plus date and you can never mix two vials up.
bacteriostatic water has the preservative, sterile water does not
dilara_szabo has the units point exactly right. They are a volume on the barrel and nothing else.
if the maths gives you a fraction of a unit, change the concentration
Pushback on the syringe advice: a U-100 barrel reads units of volume. Calling them "doses" is how the confusion starts.
Adding more water does not change how much peptide is in the vial. It changes the concentration, which changes the volume you draw for the same amount. That is the entire relationship.
Research-use-only material is not approved for human use, so treat everything in this thread as arithmetic about solutions rather than instructions for a person.
The lyophilised cake displaces a small volume, so the true concentration is very slightly lower than the arithmetic suggests. It is a fraction of a percent and it is dwarfed by fill tolerance.
Disagree with the "more water is safer" framing. It is not safer, it is just a different number to divide by.
Careful — that arithmetic is wrong. 15mg in 3mL is 5mg/mL, so 0.75mg draws to 15 units, not what you wrote.
That is sterile water, not bacteriostatic. Same appearance, different product, and it matters for a multi-draw vial.