Stated plainly: dulaglutide · minus 80 °C · ten days.
I would like to set this up properly once, rather than adjust it repeatedly.
My budget is real but not tight, and my tolerance for uncertainty is low.
What should I decide now, and what should I defer?
Ten days at minus 80 °C. minus 80 °C is 85 kelvin below a refrigerator, and below the glass transition of a lyophilised cake the ten-degree rule of thumb stops applying at all — solid-state chemistry is not slow liquid chemistry, it is a different regime, and the failure modes that survive it are mechanical rather than chemical. The thing to establish is how many times it froze and thawed, not how long it sat: ten days at one stable temperature is gentler than a single uncontrolled transition. Either way, record the ten days and the temperature now, while you still know them; an excursion you did not write down is an excursion you cannot interpret later.
Start with the physical state, because it changes the answer completely and is the first thing to establish.
That is the argument for shipping lyophilised rather than for shipping colder. A dry powder with low residual moisture is stable at ambient for months; the pathways that matter need water.
A single-use temperature logger costs a few pounds, records the whole journey and converts an argument into a record. If the history matters, this is the answer.
Arrhenius kinetics predict approximately a doubling of degradation rate per ten-degree rise and are the standard basis for cold-chain design.
Reconstituted material has a genuine cold-chain requirement and it starts the moment water is added.
A liquefied pack is expected. It is not evidence of a problem.
Analytical standards and reagents with traceable certificates. Every quantitative result you read inherits the accuracy of the standard behind it.
Shop standardsThe short version: a spent cold pack on arrival is expected, the solid does not mind, and the pack was never going to last twelve days.
Anything shipped in solution is a different risk category, because hydrolysis and deamidation proceed in the aqueous phase and are strongly temperature-dependent.
Stated carefully, arrhenius behaviour means the degradation rate roughly doubles per ten degrees. A week at thirty degrees is therefore a meaningful exposure for a solution and an immaterial one for a dry solid.
Buy a logger if you actually want to know. Everything else is inference.
edited 14 Feb 2026 by marta_okonkwo — removed a claim I could not source
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