How long does semaglutide stay within specification at 25 °C once reconstituted?

Concretely: semaglutide · 25 °C.

I am trying to do this correctly the first time rather than learn it by getting it wrong.

I have already made one mistake here that cost me a vial, so I am being deliberately careful.

What would you do, and what would you check afterwards?

Whatever the refrigerated figure is, divide it by about 4. 25 °C is 20 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 4 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 7 days at 25 °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.

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

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.

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.

Put another way, 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.

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

The relevant point is that a mass shift of plus one dalton is deamidation and plus sixteen is oxidation, so degradation is often visible in a mass spectrum if anyone looks.

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.

Stated carefully, 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.

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

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

edited 13 Jun 2025 by ten_mg_vial — corrected a unit error in the worked example