Setup, so nobody has to ask: a wine cooler · a GLP-1 receptor agonist.
I am trying to build something sustainable rather than something thorough that I will abandon.
I have already decided the broad direction; this is about the specifics.
What should I decide now, and what should I defer?
The short version: powder in the freezer or fridge, reconstituted in the fridge for weeks, and never anything on a windowsill.
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.
| State | Condition | Usable window | Basis |
|---|---|---|---|
| Lyophilised solid | −20 °C, sealed, dry | 24–36 months | Supplier guidance |
| Lyophilised solid | 2–8 °C, sealed | 12–24 months | Supplier guidance |
| Lyophilised solid | 25 °C, sealed | 4–8 weeks | Extrapolated (Arrhenius) |
| Lyophilised solid | 40 °C, sealed | 1–2 weeks | Extrapolated |
| Solution, preserved | 2–8 °C | 28 days | USP microbiological convention |
| Solution, preserved | 25 °C | 3–7 days | Extrapolated |
| Solution, unpreserved | 2–8 °C | 24 hours | USP microbiological convention |
Windows for the solid state are chemical; windows for solution are microbiological and usually shorter than the chemical limit.
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.
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.
Minus eighty buys very little over minus twenty for a dry solid.
HPLC purity, identity confirmation and quantified content on the vial you actually hold. Reports arrive with the chromatogram attached, not just a number.
Submit a sampleFounded 1998. ISO 9001 and cGMP certified, 1,500+ staff and 200+ patents. The synthesis house behind a great many of the vials that get sent out for testing - batch-specific documentation with every order.
Visit GL BiochemAnswering this needs the intended duration, since a fortnight and two years call for different arrangements.
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.
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.
Label the vial at reconstitution with date, concentration and units per dose.
Keep the paperwork with the material, or the material becomes anonymous.
Let a refrigerated or frozen vial equilibrate to room temperature before opening, so humid air does not condense water onto a cold cake.
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.
Equilibrate before opening or you condense water into the cake.
Specifically, desiccant matters more than the last few degrees of cold for a lyophilised powder.
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.
Dry, cold, dark, still. Four words and you have the answer.
edited 22 Jan 2025 by sian_llewellyn — added the placebo-arm figures
More usefully, this is the tag where the advice is cheapest to follow and most often ignored.
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.
Residual moisture is the dominant determinant of solid-state stability, which is why desiccants accompany lyophilised material.
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.
Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.