Before you open a vial
- Bring the sealed vial to room temperature — opening a cold vial pulls in moisture
- Confirm the label against your inventory record and the certificate of analysis
- Prepare your labelling before reconstitution, not after
- Work in a clean area with the stopper wiped and dried
- This page is reference information for laboratory personnel handling research materials. It contains no medical, dosing, or human-use guidance of any kind.
Solvent selection
Bacteriostatic water contains a preservative and suits preparations that will be accessed more than once. Sterile water contains no preservative and suits single-use preparations. Acetic acid solutions are used for peptides with poor aqueous solubility, and the choice should be driven by the compound's documented solubility rather than by habit.
Whatever is chosen, record it. Concentration is not reconstructible later without knowing both the solvent and the volume added.
Calculating concentration
Concentration is the vial's labelled mass divided by the solvent volume added. A 10 mg vial reconstituted with 2 mL yields 5 mg per mL. A 30 mg vial reconstituted with 3 mL yields 10 mg per mL.
The labelled mass is the figure on the vial, not an estimate from the cake's appearance. Lyophilised cakes vary in visible bulk between lots without any difference in mass.
Technique
- Add solvent slowly down the vial wall, never directly onto the cake
- Let dissolution happen passively; swirl gently rather than shaking
- Never vortex — shear degrades peptide chains
- Confirm a clear solution with no particulate before use
- Do not force a poorly soluble peptide with heat
Aliquoting and freeze-thaw
Each freeze-thaw cycle costs peptide integrity. Where a preparation will be accessed repeatedly, split it into single-use aliquots immediately after reconstitution so the bulk never cycles.
Aliquots should be labelled with the compound, concentration, solvent, and preparation date. An unlabelled aliquot is unusable material regardless of what is in it.
Storage summary
- Lyophilised, sealed: cold, dark, stable temperature, original packaging
- Reconstituted: refrigerated, light-protected, short window
- Aliquots: frozen, single-use, fully labelled
- All states: never store without lot traceability back to the certificate of analysis