The peptide arrives as a dry powder and, to work with it, it has to be brought back into solution. The most common solvent in research is bacteriostatic water (sterile water with 0.9% benzyl alcohol), because it allows volume to be drawn from the same vial several times while reducing the risk of contamination. Some poorly soluble peptides need a slightly acidic medium.
The technique follows simple rules: let the vial reach room temperature, disinfect the stopper, add the solvent slowly running it down the wall of the vial rather than aiming at the powder, and dissolve by swirling gently, without shaking. Shaking creates foam and air-liquid interfaces where the peptide unfolds and aggregates.
The amount of solvent does not change the amount of peptide, only its concentration. Choosing a round volume makes every later calculation easier.
Once reconstituted, the peptide loses the stability of the dry state: it must be kept refrigerated and protected from light, and its shelf life is then measured in weeks. It is worth writing the reconstitution date on the vial itself.
Related terms
Learn it in depth at the Peptide University
- Practical calculation cases and common errors · Module 9
- Reconstitution and aseptic technique · Module 9
- The lyophilized form and its diluents · Module 8
- The arithmetic of concentration · Module 9
- Stability and storage · Module 9
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Definition for educational and scientific purposes. It is not medical advice or a recommendation for use. NeoPeptidos products are sold labelled for research use only (RUO).