Lyophilisation (freeze-drying) removes water from a peptide so it stays stable far longer than it would in solution. The powder is robust, but not indestructible: heat, moisture, light and air all degrade it over time. These are the storage practices most laboratories follow.
Temperature
- Long-term storage: −20 °C or colder, in a freezer that does not run auto-defrost cycles if possible.
- Short-term storage: 2–8 °C (a standard laboratory refrigerator) for days to weeks.
- Transit: freeze-dried peptides generally tolerate a few days at ambient temperature. Cold packs during shipping add a safety margin, especially in summer.
Record the temperature conditions on arrival. If a parcel arrives warm after a long delay, note it against the batch.
Moisture
Water is the main enemy of a lyophilised powder. The cake absorbs moisture from the air, which speeds up degradation.
- Keep vials sealed until they are needed.
- Let a cold vial reach room temperature before opening it. Opening a cold vial pulls condensation onto the powder.
- Store vials with a desiccant in a closed container where practical.
Light and air
Some amino acids, such as tryptophan, methionine and cysteine, are sensitive to light and oxidation. Keep vials in their box or in an opaque container, and limit the time they spend open.
Freeze–thaw cycles
Repeated freezing and thawing damages peptides, particularly once they are in solution. Laboratories usually divide material into single-use portions (aliquots) so that each portion is thawed only once.
Solutions are less stable than powder
Once a peptide is dissolved, its stability drops sharply and depends on the solvent, pH, concentration and temperature. Follow the methods in the published literature for your specific application. R3TA does not provide protocols for preparing solutions for administration.
Keep records
Good records make results traceable:
- batch number and COA for each vial;
- date received and storage location;
- date opened and any deviations (for example a warm delivery).
R3TA labels every vial with its batch number and ships each order in an insulated box with gel packs. Storage conditions for R3TA vials: −20 °C, protected from light.