[Meta] proposal — a flair for bacteriostatic water posts
Putting this to the board: proposal — a flair for bacteriostatic water posts. Aim the stream down the wall of the vial rather than into the cake. Reconstitution is a solubility problem, not a mixing problem, and mechanical shear does nothing helpful. The lyophilised cake displaces a small volume, so the true…
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.
Small fix — a U-100 syringe is 100 units per mL. If yours is marked differently it is not U-100 and the whole calculation changes.
How many mg in the vial and how many mL are you adding?
What is written on the vial right now?
That only works if the fill weight is exactly the label weight, and it usually is not exactly anything.
Right — the volume you add is the only variable you control here, and the cake does not change it meaningfully.
That is sterile water, not bacteriostatic. Same appearance, different product, and it matters for a multi-draw vial.
Yes, and the dead-space point is worth repeating: it is small, it is real, and it is the same for every draw.
the powder cake sits at the bottom, the volume you add is the volume that counts
if the maths gives you a fraction of a unit, change the concentration