How to store and handle lyophilised peptides

The powder is forgiving, within limits

A sealed vial of lyophilised peptide at ambient temperature is the normal shipping condition. What damages it is moisture ingress and repeated temperature cycling, not the ambient temperature itself.

For storage beyond three months, −20 °C is preferable to ambient. The important word is cycling: a vial that moves between −20 °C and room temperature ten times is worse off than one held continuously at either end.

Moisture is the real enemy

Lyophilised cakes are hygroscopic. Opening a vial in a humid room lets the cake absorb water, and a partially hydrated cake degrades faster than a fully reconstituted one that is kept cold.

Practical rule: let a cold vial reach room temperature in its sealed state before opening it. Opening a cold vial invites condensation on the inside of the glass.

Reconstitution decisions

Use bacteriostatic water where repeated withdrawals are planned and sterile water where a single session is planned. Bacteriostatic water contains 0.9% benzyl alcohol, which suppresses microbial growth between withdrawals.

Add the diluent down the wall of the vial rather than onto the cake, and swirl rather than shake. Mechanical shear is a real degradation route for larger peptides.

Light, labels and record keeping

Several sequences are light-sensitive in solution, which is why amber glass and opaque secondary cartons appear in the catalogue for those lines.

Write the reconstitution date on the vial, not on the box. The box is the first thing separated from the vial in a working refrigerator.

Research use only. Not for human or veterinary use.