Is 40 °C an acceptable storage condition for lyophilised orforglipron?

Numbers first: 40 °C · orforglipron.

I would rather be corrected now than propagate something wrong.

I am specifically not interested in a testimonial; I am interested in a measurement.

Is this actually true, and what is the evidence?

40 °C is above the refrigerated band, and how far above is the whole answer. 40 °C is 35 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 11 times the refrigerated rate, which is an order-of-magnitude statement and not a shelf life. Lyophilised material tolerates this far better than solution does, which is why it is shipped that way, but "tolerates" is a statement about weeks and the vial is being asked about months. Log the excursion rather than guess at it. Nothing here is medical advice, and research-use-only material is not approved for human use.

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

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.

Degradation pathway by condition

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.

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

Minus eighty buys very little over minus twenty for a dry solid.

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

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

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.

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.

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

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

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.

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.

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.

Residual moisture is the dominant determinant of solid-state stability, which is why desiccants accompany lyophilised material.

Equilibrate before opening or you condense water into the cake.

edited 19 Jul 2024 by h_pergande — added the method parameters

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

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.

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

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.

The short version: powder in the freezer or fridge, reconstituted in the fridge for weeks, and never anything on a windowsill.

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.

Deamidation kinetics for asparagine in peptides are well characterised and strongly sequence-dependent: the residue following the asparagine dominates the rate, with glycine and serine at the n+1 position accelerating it by an order of magnitude relative to bulkier residues. That is why two peptides in the same buffer at the same temperature can have quite different shelf lives.

A printed expiry on research-grade material has no stability programme behind it.

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