Technical library
Storage and stability
Most material that underperforms was not badly made. It was badly kept, usually in a way nobody recorded at the time.
Conditions
What to hold, and where
| Lyophilised, in transit | Ambient transit is normally tolerated for short periods. What matters is total time and peak temperature, not whether a cold pack was still cold on arrival. |
|---|---|
| Lyophilised, on receipt | Refrigerated at 2 to 8 degrees Celsius, dry, away from light, is the usual specification. Long-term holding may call for frozen storage. |
| Reconstituted | Refrigerated, and subject to a materially shorter life than the lyophilised form. Reconstitution starts a clock that the dry powder was not subject to. |
| Light | Amber vials or opaque secondary packaging. Light exposure is cumulative and is not reversed by returning material to the dark. |
| Freeze and thaw | Repeated cycles are the avoidable damage. Aliquot before freezing so a single vial is not thawed and refrozen repeatedly. |
| Humidity | Lyophilised material is hygroscopic. A vial opened in a humid room takes on water that never fully leaves. |
Record the receipt as well as the order. Date of arrival, condition on arrival, and transit duration. Without those three, a later question about a batch has no evidence behind it and becomes an argument.
Why it degrades
Four mechanisms worth knowing
Hydrolysis
Water is the reason lyophilised material is stable and reconstituted material is not. Removing water is what gives the dry form its shelf life, and adding it back is what ends it.
Oxidation
Air exposure at each opening, cumulative across the life of a vial. Fewer openings is better than shorter openings.
Aggregation
Driven largely by mechanical and thermal stress, which is why repeated freeze and thaw cycles matter more than a single cold excursion.
Light
Cumulative and irreversible. Secondary packaging exists for this and works only if the material is actually kept in it.
Procurement
How to specify this in an agreement
Name the storage condition for the lyophilised form, name it separately for the reconstituted form, and state who bears the risk during transit and from what point. Then say what evidence is required if a batch is questioned: batch number, certificate, receipt date, and storage record.
That clause takes four lines and removes most of the ambiguity that otherwise surfaces at the worst possible moment.
Questions
Storage, answered
Does a warm shipment mean the material is compromised?
Not automatically. Lyophilised peptides generally tolerate short ambient excursions. The meaningful question is cumulative time and peak temperature, which is why transit duration is worth recording on receipt.
How long does a reconstituted vial last?
Materially less than the dry form, and it varies by compound and by diluent. Record the reconstitution date and count a new shelf life from it.
Should storage conditions be in the supply agreement?
Yes. If conditions are not specified in writing, there is no agreed standard to point to when a shipment is questioned, and the discussion becomes a matter of opinion.
Does the certificate tell us the shelf life?
It gives the analysis date and, where applicable, a retest date. Shelf life is a function of that date plus the storage conditions actually maintained since, which only your own records can establish.
What is the single most common storage mistake?
Repeated freeze and thaw cycles on a vial that was never aliquoted. It is entirely avoidable and it is invisible until something does not behave as expected.
Supply enquiries
Storage conditions for every compound we supply are stated on its page and on its certificate.
| Working through a supplier decision? Tell us the compounds and the market. | Talk to us |
Also in the library
Related reference material
How to choose a peptide supplier
Eight checkable questions for vetting any wholesale supplier, including this one.
Procurement glossary
What the terms on a peptide quote mean, so two suppliers can be compared like for like.
Reconstitution concentration calculator
Work out the concentration of a reconstituted vial, how much compound sits in a given draw volume, and how many draws a vial yields.
How to read a Certificate of Analysis
What a batch certificate must contain, what each section actually tells you, and the six ways a weak certificate gives itself away.