dead space is the most under-discussed thing on this board
dead space is the most under-discussed thing on this board, and I am aware this is a minority view on this board. The whole calculation, once, with real numbers. You have a 5mg vial. You add 3mL of bacteriostatic water. Concentration is mass over volume: 1.67mg/mL. A U-100 insulin syringe is graduated at 100 units…
Why "more water" keeps confusing people, including me for a month.
The vial contains a fixed amount of peptide. Water changes nothing about that amount. What it changes is concentration, and concentration is the divisor between the dose you want and the volume you draw.
So doubling the water halves the concentration and doubles the units for the same dose. Nothing is diluted in any sense that matters; you are simply reading a bigger number off the same barrel. Pick the water volume that puts your usual dose on a whole number of units and life gets easier.
Bacteriostatic or plain sterile water?
That is sterile water, not bacteriostatic. Same appearance, different product, and it matters for a multi-draw vial.
a U-100 syringe reads 100 units to the millilitre, every time
Spent 21 weeks confused about this until somebody drew the table for me. 5mg, 2mL, 2.5mg/mL, 0.75mg is 30 units. That is the whole thing.
label the vial with the date as well as the concentration
bacteriostatic water has the preservative, sterile water does not