Practical handling notes for qualified researchers working with lyophilised peptides. Pair these with the peptide calculator when planning a protocol.
Reconstituting a lyophilised vial
Bring the vial to room temperature, swab the stopper, and run bacteriostatic water slowly down the inner glass wall. Swirl — never shake — until the solution is completely clear with no visible particulate.
- Use bacteriostatic water for multi-draw vials; sterile water is single-use only.
- 2 mL of diluent in a 10 mg vial gives 5 mg/mL — 250 mcg is 5 units on a 100-unit syringe.
- Label the vial with the date of reconstitution and the resulting concentration.
Cold chain and storage
Lyophilised powder is stable at 2–8°C for months and at −20°C for long-term archives. Once in solution, peptides degrade far faster and should be treated as short-lived material.
- Lyophilised: 2–8°C short term, −20°C long term, protected from light.
- Reconstituted: refrigerate at 2–8°C and use within roughly 28 days.
- Avoid repeated freeze–thaw cycles; aliquot instead where the protocol allows.
Choosing a syringe
Match the syringe to the volume you actually draw. Small volumes measured on a large barrel introduce the biggest percentage error in a study.
- Draws under 0.3 mL: use a 30-unit barrel for readable graduations.
- 0.3–0.5 mL: 50-unit barrel.
- Above 0.5 mL: 100-unit barrel, or split the draw.
Reading a certificate of analysis
A COA should identify the lot, the analytical method and the acceptance criteria. If any of those three are missing, the document is marketing rather than evidence.
- HPLC chromatogram with a purity percentage against the main peak.
- Mass spectrometry confirming the expected molecular weight.
- Lot number and test date that match the label on your vial.
Safe handling in the lab
Treat every compound as an unknown biological hazard. Gloves, eye protection and a documented disposal route are the minimum for any peptide work.
- Work on a disinfected surface; discard sharps into an approved container.
- Never re-enter a vial with a used needle.
- Keep a written log of lot numbers against experimental runs.