Reconstitution Basics for Lyophilised Peptides

Research peptides are supplied as a lyophilised powder, freeze-dried to a stable solid. Before any measurement, the powder is reconstituted: brought into solution with a diluent. The concentration of that solution is set by two numbers, the mass of peptide in the vial and the volume of diluent added. A 5 mg vial brought up in 2 mL of diluent gives 2.5 mg/mL. Adding 1 mL instead gives 5 mg/mL. The powder mass is fixed by the vial; the concentration is chosen through the volume added.

Technique protects the material. Diluent is directed against the wall of the vial rather than sprayed onto the powder, because peptides can be sensitive to mechanical shear at the surface. The vial is swirled, not shaken, and left to dissolve rather than forced. Reconstituted peptide is generally less stable than the dry powder and is kept cold and protected from light.

Diluent choice follows the handling plan, which is where bacteriostatic and sterile water differ. That distinction is covered in its own article.

This piece describes laboratory handling of research material. It is not preparation guidance for administration. For the concentration arithmetic, the Peptheos Reconstitution Calculator does the volumes.