The method for mixing a lyophilized peptide is the same for nearly every compound: choose a diluent volume, add bacteriostatic water gently, dissolve without shaking, then label and store. This guide covers the general procedure. For compound-specific notes, follow the links to the individual guides.
Why bacteriostatic water
Bacteriostatic water is sterile water containing 0.9% benzyl alcohol, which inhibits bacterial growth. That is why it is the usual diluent for multi-use research vials. Sterile water has no preservative, so once opened it offers no ongoing protection. Our guide to what bacteriostatic water is explains the difference in detail.
The procedure
- Prepare the workspace. Clean surface, hands washed, supplies laid out.
- Bring the vial to room temperature if it was stored cold.
- Wipe both stoppers with alcohol swabs and let them dry.
- Choose the volume. Concentration is peptide amount divided by diluent volume. For example, 5 mg in 2 mL is 2.5 mg per mL. The calculator handles any combination.
- Draw the bacteriostatic water into a sterile syringe.
- Add it slowly down the inside wall of the peptide vial, never directly onto the powder.
- Swirl gently until clear. Do not shake.
- Label the vial with the date and concentration.
- Refrigerate at about 2-8 °C and protect from light.
How much water should you use
There is no single correct volume. A smaller volume gives a more concentrated solution and a larger one gives a more dilute solution that is easier to measure precisely. Pick the volume that fits your protocol and write it down. The arithmetic is covered in reconstitution calculations.
Compound-specific guides
Bacteriostatic water is also stocked here: 10 mL vial.
For laboratory research use only. Not for human or animal consumption.