Handling lyophilised peptides in the lab: receipt to storage

Definitions

• Lyophilisation: freeze-drying; water is removed from a frozen sample under vacuum, leaving a dry cake or powder.
• Hygroscopic: tending to absorb moisture from the air. Many lyophilised peptides are.
• Aliquot: a portion of a stock divided off so the remainder is not repeatedly opened or thawed.

On receipt

• Check each vial is sealed and the cake or powder is intact.
• Record the compound, vial size and the printed lot number in your lab log before storage.
• Request or file the lot's CoA and confirm the lot number matches.
• Move vials to cold storage promptly; for the temperatures used, see our storage and solubility reference data.

Keeping moisture out

Let a cold vial reach room temperature, unopened, before opening it, so atmospheric water does not condense on the cold powder. Open briefly, reseal, and consider a desiccator for opened vials. Moisture uptake is a well-documented cause of degradation and aggregation in lyophilised protein and peptide solids.

Source: Moisture-induced aggregation of lyophilized insulin, Pharm Res 1994 (PubMed 8140052)

Solutions and aliquots

• Peptides in solution are much less stable than the dry solid; prepare solutions as needed for the experiment.
• If a stock must be kept, divide it into single-use aliquots so each is thawed once.
• Label every aliquot with compound, concentration, date and the source lot number.
• Use the concentration calculator for mg/mL arithmetic, and account for net peptide content.

Records that make results reproducible

Linking each experiment to the lot number lets you trace an unexpected result back to a specific lot and its certificate. Sable prints a lot number on every vial and holds a CoA for every lot.

Frequently asked questions