How long does orforglipron stay within specification at 37 °C once reconstituted?

Setup, so nobody has to ask: orforglipron · 37 °C.

This is a procedural question rather than a theoretical one, and I would like the procedure rather than the theory.

What I have done so far is read the label documentation where it exists and the two pharmacopoeial monographs that are publicly available, which cover the licensed presentation and say nothing about a research one.

What does a defensible version of this look like in practice?

Whatever the refrigerated figure is, divide it by about 9.2. 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. So a preparation with a twenty-eight day refrigerated figure has roughly 3 days at 37 °C on the same assumption — an order-of-magnitude answer, not a shelf life, and it says nothing about sterility, which has its own clock. "Within specification" also needs a specification: purity, content, or both, and at what limit. Without that the question has no numerical answer at all.

To be exact about it, aggregation is a physical process and is the one most often caused by handling rather than by time.

Oxidation targets methionine, cysteine and tryptophan, adding sixteen daltons per oxygen. It is catalysed by trace metals and promoted by dissolved oxygen and by light.

Reported and extrapolated stability by condition

Windows for the solid state are chemical; windows for solution are microbiological and usually shorter than the chemical limit.

Aggregation is physical: peptides unfold at air-liquid interfaces and associate. Shaking maximises that interface, which is why swirling and shaking produce visibly different outcomes on the same vial.

Swirl, never shake. Aggregation is a handling problem more than a time problem.

Answering this needs the physical state, since a dry powder is protected from most of these and a solution is protected from none.

Freeze-thaw cycling drives aggregation through concentration at the ice interface and pH shifts as buffer components crystallise out at different rates. Each cycle costs something.

A mass spectrum resolves most of this: minus eighteen is dehydration or succinimide, plus one is deamidation, plus sixteen is oxidation, and an unchanged mass with a shifted retention time is an isomer.

Aggregation at air-liquid interfaces is established from surface-tension and particle-count studies and is the basis for anti-agitation handling guidance.

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

Sequence decides which pathways are even available. Check the residues.

edited 14 Mar 2025 by Dr_Jonas_Halvorsen — tightened the wording; no substantive change

The short version: water enables most of it, oxygen enables oxidation, surfaces enable adsorption, and agitation enables aggregation.

Deamidation converts asparagine or glutamine to the corresponding acid via a succinimide intermediate, adding one dalton. It is base-catalysed, accelerates above neutral pH and is the dominant aqueous pathway for many peptides.

Worth being precise here: adsorption onto glass and plastic is significant at low concentrations — micrograms per millilitre — and negligible at milligrams per millilitre. It is the usual explanation for an apparent loss in a dilute preparation.

Adsorption losses at low concentrations are quantified in formulation studies and are the reason carrier proteins are used in dilute preparations.

The caveat is that none of these pathways can be seen by looking at a vial, and a clear solution can be substantially degraded.

A mass spectrum names the pathway. Plus one, plus sixteen, minus eighteen.

Asparagine and glutamine are the deamidation risk, and methionine is the oxidation risk.

Hydrolysis cleaves the backbone, most readily at aspartate-proline and aspartate-glycine sequences, and is acid-catalysed. In a dry solid it barely proceeds at all.

Metal-catalysed oxidation of methionine is documented across peptide and protein formulations and is why chelators appear in some formulations.

Cold, dry, dark, still. Those four words cover most of the mitigation.

Start with the sequence, because which pathways are available depends on which residues are present.

Light exposure matters for tryptophan-containing sequences and for anything with a chromophore. Amber vials and a closed box are free mitigations.

At dilute concentrations, suspect adsorption before you suspect chemistry.