Is survodutide at 20 mg/mL stable enough for ten weeks of multi-withdrawal use?

Conditions: survodutide · 20 mg/mL · ten weeks.

The claim is plausible, which is exactly why I want to check it.

I am able to read a paper if someone points me at one.

Can anyone point me at a primary source, or confirm that there is not one?

ten weeks is 70 days and, on a weekly schedule, 10 stopper punctures out of one vial at 20 mg/mL. Set the chemical question aside for a moment, because the puncture count is the one with a convention attached: 70 days is 2.5 times the twenty-eight days conventionally allowed for a preserved multi-dose preparation once it has been entered. Chemically, 20 mg/mL is high enough that adsorption to the glass is a rounding error and low enough that it is not protecting you from anything. What 10 withdrawals do add is 10 opportunities to introduce air, 10 coring events on the same stopper, and a headspace that grows with every draw — none of which show up on a certificate and all of which are avoided by splitting into aliquots at reconstitution.

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.

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

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

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

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

Answer first: the degradation pathways worth knowing are hydrolysis, deamidation, oxidation, aggregation and adsorption, and each has a different trigger and a different mitigation.

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.

Stated carefully, 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.

Deamidation via the succinimide intermediate is well characterised, with sequence-dependent rates highest for asparagine-glycine motifs.

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

edited 28 Dec 2025 by ten_mg_vial — corrected a unit error in the worked example