Lyophilised peptide is a stable material, which is why it survives a courier network without refrigeration. Most of the degradation researchers actually encounter happens after the vial is opened, in the first ten minutes, and is entirely avoidable.
Let the vial reach room temperature first
Opening a cold vial pulls humid air in. The powder takes up that moisture, and a hygroscopic peptide that has absorbed water has a shorter shelf life than one that has not. Take the vial out, leave it sealed on the bench, and give it twenty minutes.
Direct the solvent down the wall
Bacteriostatic or sterile water, drawn into a syringe, introduced against the inside wall of the vial rather than fired directly into the powder. A jet delivered straight onto lyophilised material shears the chain — you lose product before the solution is even mixed.
Then swirl. Do not shake, do not vortex. Peptides denature at air–liquid interfaces, and vigorous agitation manufactures a great many of those interfaces very quickly.
Write on the vial before you put the syringe down
Concentration is milligrams divided by millilitres: a 10 mg vial reconstituted with 2 mL is 5 mg/mL. This is trivial arithmetic and it is the single most common source of error in downstream work, because it is done from memory an hour later. Compound, concentration, date — on the vial, at the moment of reconstitution.
Storage
| Lyophilised, sealed | -20°C for long-term storage. Room temperature is fine in transit. |
|---|---|
| Reconstituted | 2–8°C, protected from light. Use within the window on the certificate. |
| Freeze–thaw | Aliquot into single-use volumes. Repeated cycles cost you material every time. |
| Light | Keep in the supplied vial. Some sequences are photosensitive and none benefit from the exposure. |
Disposal
Unused material and sharps go through your institution’s chemical waste procedure. Reconstituted peptide does not go down a drain.
Research use only
Everything above concerns laboratory handling of research compounds. These products are not approved for human or veterinary use, have not been evaluated by the Food and Drug Administration, and must not be administered to people or animals.