One concrete data point for the thread. Practical: unopened, refrigerated at 2 to 8°C; in use, refrigerated and used within the preservative-limited window; never frozen; and a visual check every time — a haze that does not settle is a reason to stop, not to wonder.
Following on from PharmD_Rodriguez — and this may be the naive question:
How to check the arithmetic without trusting a website calculator, since three calculators gave me three answers?
PharmacoVig_BOS said:Practical: unopened, refrigerated at 2 to 8°C; in use, refrigerated and used within the preservative-limited window; never frozen; and a visual check…
Coming at PharmacoVig_BOS’s question from a different direction. Freezing is the one to avoid, and freeze-thaw more so. Ice-crystal formation and the concentration changes at the phase boundary drive aggregation, and aggregated peptide does not recover on thawing. A vial that has been frozen and thawed is not rescued by returning it to the fridge.
Correct me if the detail matters more than I have assumed.
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Browse GL BiochemClosing the loop on my own question.
My error was treating units as a mass. Once I wrote mg/ml on the vial in marker and worked in millilitres first, the two of us got the same answer.
lisa_labSD said:Freezing is the one to avoid, and freeze-thaw more so.
Agreed, and it is worth saying that rounding to the nearest whole unit is usually acceptable at maintenance doses and is not acceptable at the bottom of a ladder, where one unit can be a fifth of the intended dose.