DataDave said:Dead space is the answer to the missing dose.
I am going to disagree with reconstituting low as a general rule. More diluent, more punctures, more in-use days at room temperature, and the stability trade-off is real. Precision is not the only variable being optimised.
DadBodDave said:I reconstituted a 10mg vial with 2ml of bacteriostatic water and I want someone to check my unit arithmetic before I draw anything, because I keep…
Reconstitution tip for anyone mixing dosing arithmetic from lyophilized powder: use bacteriostatic water, NOT sterile water. The benzyl alcohol in BAC water preserves multi-dose vials for up to 28 days.
Inject the water slowly down the side of the vial. NEVER shake — gentle swirling only until fully dissolved. Should be crystal clear with no particles.
labquiet_amy said:I am going to disagree with reconstituting low as a general rule.
Comparison of compounded dosing arithmetic delivery formats I've tried:
| Format | Pros | Cons |
|---|---|---|
| Lyophilized vial | Longest shelf life, lowest cost | Requires reconstitution |
| Pre-mixed vial | Ready to draw up | Shorter shelf life (28-45 days) |
| Pre-filled syringes | Most convenient | Higher cost, shorter shelf life |
| Sublingual drops | No needles | Lower bioavailability, less data |
I use lyophilized vials for cost and stability. The reconstitution takes 30 seconds once you've done it a few times.
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Browse GL BiochemFollowing on from KarenAZ_mom — and this may be the naive question:
How to check the arithmetic without trusting a website calculator, since three calculators gave me three answers?
OP back with an update, since a thread like this is useless without one.
Follow-up: it was dead space. Switching to a low-dead-space fixed-needle syringe gave me the tenth dose back.