Is minus 20 °C an acceptable storage condition for lyophilised a GLP-1 receptor agonist?

What I am working with: minus 20 °C · a GLP-1 receptor agonist.

This is asserted often enough that I assumed it was established, and then I went looking for the source.

I have searched the primary literature and found one paper that is adjacent but not on point.

Is there data behind this, or is it received wisdom?

Answering this needs the intended duration, since a fortnight and two years call for different arrangements.

Let a refrigerated or frozen vial equilibrate to room temperature before opening, so humid air does not condense water onto a cold cake.

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.

Equilibrate before opening or you condense water into the cake.

edited 28 Aug 2024 by leonid_marchuk — expanded the table to cover the lower concentration

Desiccant matters more than the last few degrees of cold for a lyophilised powder.

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.

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.

Appearance does not indicate stability; a normal-looking cake can be substantially degraded.

Label the vial at reconstitution with date, concentration and units per dose.

This is the tag where the advice is cheapest to follow and most often ignored.

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.

Photodegradation of tryptophan-containing peptides is documented and is the basis for light-protected storage recommendations.

The caveat is that storage conditions preserve what you have and cannot improve it.

Dry, cold, dark, still. Four words and you have the answer.

The honest answer is that ordinary refrigeration handles almost every case people ask about.

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.

Two-to-eight-degree refrigeration and minus-twenty freezing are the standard storage conditions for lyophilised peptides in supplier documentation across the market.

Nothing here is medical advice, and research-use compounds are not approved for human use.

Keep the desiccant with the vial and the certificate with the lot code.