Step-by-step laboratory procedure for reconstituting a lyophilised vial with bacteriostatic water, including volume selection, swirling technique and labelling.
Never shake a reconstituted vial
Mechanical shear and foaming damage peptide structure. Add diluent slowly down the vial wall and swirl gently until the solution is completely clear.
Before you start
- Let the vial reach room temperature — around 20 minutes out of the refrigerator.
- Confirm the batch code on the label matches the certificate of analysis.
- Work on a clean, dedicated surface with gloves and eye protection.
- Have bacteriostatic water, an appropriate syringe and a labelled destination ready.
- Decide the target concentration before you draw any diluent.
Procedure
- Wipe both the peptide vial stopper and the bacteriostatic water stopper with an alcohol swab and let them dry.
- Draw the calculated volume of bacteriostatic water into the syringe.
- Insert the needle at an angle and let the water run slowly down the inside wall of the vial — never straight onto the powder.
- Withdraw the needle and leave the vial to stand; most peptides dissolve within a minute or two.
- If material remains, swirl or roll gently between the fingers. Do not shake — mechanical shear and foaming damage peptide structure.
- Inspect: the solution should be completely clear and free of particulates.
- Label immediately with compound, batch, concentration, diluent and reconstitution date.
Choosing a volume
Concentration is simply peptide quantity divided by diluent volume: a 10 mg vial reconstituted with 2 ml gives 5 mg/ml, or 5000 mcg per ml. Larger volumes make small measurements easier to draw accurately; smaller volumes conserve fridge space and reduce the working stock’s exposure. Two millilitres is a common default because it makes the arithmetic clean.
The reconstitution calculator in Tools & Calculators does this arithmetic for you, including the equivalent syringe units.
After reconstitution
- Refrigerate at 2–8 °C and protect from light.
- Aliquot if the stock will be used repeatedly, to avoid freeze-thaw cycling and repeated septum entry.
- Treat the solution as a short-lived working stock rather than long-term storage.
- Never return withdrawn material to the vial.
Supplied for laboratory research use only. Not for human or veterinary use.