For reference: liraglutide · 37 °C · fourteen days.
I am at the decision point and I would rather think it through than improvise.
I would rather spend money on measurement than on redundancy.
How do I make this decision on evidence rather than on feel?
Fourteen days at 37 °C is about 129 refrigerated days of equivalent exposure. 37 °C is 32 kelvin above the 5 °C middle of a 2–8 °C refrigerator. The ten-degree rule of thumb — degradation rate roughly doubling per 10 K — makes that about 9.2 times the refrigerated rate, which is an order-of-magnitude statement and not a shelf life. At 129 equivalent days a test is more likely to reassure you than to tell you something, which is a legitimate reason to run it and a poor reason to expect a finding. Either way, record the fourteen days and the temperature now, while you still know them; an excursion you did not write down is an excursion you cannot interpret later.
The 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.
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.
On the detail: once the parcel arrives, the domestic leg is the controllable part: get it into the refrigerator promptly rather than leaving it in a warm hallway for a day.
Phase-change pack hold time is a function of mass, latent heat and insulation, and published figures for small parcels are on the order of one to two days.
The caveat is that a warm transit is survivable for a solid and materially different for a solution.
Lyophilised tolerates the lane. That is the answer for almost every order.
HPLC purity, identity confirmation and quantified content on the vial you actually hold. Reports arrive with the chromatogram attached, not just a number.
Submit a sampleFounded 1998. ISO 9001 and cGMP certified, 1,500+ staff and 200+ patents. The synthesis house behind a great many of the vials that get sent out for testing - batch-specific documentation with every order.
Visit GL BiochemThe honest answer is that the cold pack is doing much less than people think and that shipping lyophilised is what actually protects the material.
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.
Asking a supplier to hold a shipment during a heatwave is reasonable and the better ones agree; the cost is a week and the benefit is a shorter warm exposure for anything in solution.
A cold pack tells you nothing about the eleven days before the last one.
Buy a logger if you actually want to know. Everything else is inference.
It helps to be literal here: the domestic leg after arrival is the part most often left in a warm hallway and least often worried about.
A pack that arrived hard tells you about the last day of transit only, since it will have melted and, if the ambient dropped, partially refrozen.
Stated carefully, 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.
Single-use temperature loggers are standard practice in supply chains where temperature genuinely matters and are inexpensive at parcel scale.
The domestic leg is the part you control. Refrigerate it promptly.
edited 29 Oct 2024 by Dr_Ilse_Vandenberg — added the method parameters
Start with the physical state, because it changes the answer completely and is the first thing to establish.
A single phase-change pack in a thin-walled box holds below ten degrees for roughly one to two days at twenty-five degrees ambient, and under a day at thirty-five. On a nine-to-fourteen-day lane the material is at ambient for most of the journey whatever was packed with it.
Solid-state stability of lyophilised peptides at ambient temperature is documented in formulation studies with residual moisture as the dominant variable.
Nothing here is medical advice, and research-use compounds are not approved for human use.
A liquefied pack is expected. It is not evidence of a problem.
Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.