The case in front of me: 4 °C · liraglutide.
I want to know whether there is evidence behind this or only repetition.
I have checked the obvious registries and monographs without success.
Has anyone verified this independently?
4 °C is inside or near the refrigerated band. 4 °C is the condition the rule of thumb is anchored to, so it is the baseline rather than a multiplier: everything else in this thread is quoted relative to it. That is the condition most lyophilised peptide is specified at, so the useful question moves to what happens after reconstitution, where the same temperature buys far less. Nothing here is medical advice, and research-use-only material is not approved for human use.
Start with the physical state, because lyophilised and reconstituted material have completely different storage answers.
Reconstituted with a preservative-containing diluent: refrigerated, conventionally treated as usable for about 28 days from first entry. Without a preservative, single use and discard.
Store with the desiccant sachet if one was supplied, inside the secondary container rather than loose in a drawer. Residual moisture is the dominant variable in solid-state stability.
Residual moisture is the dominant determinant of solid-state stability, which is why desiccants accompany lyophilised material.
Label the vial at reconstitution with date, concentration and units per dose.
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 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.
On the detail: let a refrigerated or frozen vial equilibrate to room temperature before opening, so humid air does not condense water onto a cold cake.
Two-to-eight-degree refrigeration and minus-twenty freezing are the standard storage conditions for lyophilised peptides in supplier documentation across the market.
Dry, cold, dark, still. Four words and you have the answer.
edited 3 Dec 2024 by h_pergande — fixed an arithmetic slip in the third paragraph
Keep the paperwork with the material, or the material becomes anonymous.
Keep the certificate with the vial, physically or as a photograph filed under the lot code. A vial without a traceable certificate is an anonymous vial regardless of where it came from.
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.
Photodegradation of tryptophan-containing peptides is documented and is the basis for light-protected storage recommendations.
Keep the desiccant with the vial and the certificate with the lot code.
It helps to be literal here: this is the tag where the advice is cheapest to follow and most often ignored.
Keep vials in their original carton or in an opaque box. Light exposure matters for tryptophan-containing sequences and for anything with a chromophore, and a closed box is free.
The 28-day in-use period for preservative-containing multi-dose preparations is printed on the diluent labelling and is a long-standing pharmacy convention.
Nothing here is medical advice, and research-use compounds are not approved for human use.
Equilibrate before opening or you condense water into the cake.
Answering this needs the intended duration, since a fortnight and two years call for different arrangements.
Lyophilised powder: refrigerated at two to eight degrees for months, frozen at minus twenty for longer. The gain from minus eighty over minus twenty is small for a dry solid and is not usually worth the arrangement.
A printed expiry on research-grade material has no stability programme behind it.
Minus eighty buys very little over minus twenty for a dry solid.
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.