Accepted answer
The relevant practical failure is not chemical at all: it is losing the link between a vial and its certificate when the box gets thrown away.
Position matters less than people think: upright or on its side makes no difference to a lyophilised powder, and upright is marginally better for a reconstituted vial because it keeps the stopper dry.
Label the vial at reconstitution with the date, the concentration and the resulting units per dose. This is the single most useful thirty seconds in the whole process.
Residual moisture is the dominant determinant of solid-state stability, which is why desiccants accompany lyophilised material.
Keep the desiccant with the vial and the certificate with the lot code.
edited 4 Mar 2025 by esben_lykke — expanded the table to cover the lower concentration
4Adding for future readers: the domestic leg after delivery is the part you control. – k_szabo 7 months ago 3Adding a vote because this deserves more of them. – two_two_micron 6 months ago add a comment