Reconstitution
In short Returning a lyophilised powder to solution with a laboratory diluent under controlled conditions.
Reconstitution is the step that turns the dry powder in a vial back into a solution that can be used in an experiment. It is done with a sterile laboratory diluent, added slowly down the side of the vial so the powder dissolves without vigorous shaking, which can damage some peptides.
The diluent depends on the substance. Bacteriostatic water, which contains 0.9% benzyl alcohol, suits most peptides and limits bacterial growth when a vial is opened several times. Dilute acetic acid helps dissolve some peptides that are poorly soluble at neutral pH. The choice should follow the protocol of the experiment and the literature for that compound.
Once reconstituted, a peptide is far less stable than in dry form. Solutions are kept at 2 to 8 °C, protected from light, and used within the period the protocol allows. Repeated freezing and thawing of solutions is best avoided.
UKPeps supplies the diluents but gives no instructions for use beyond laboratory handling, and does not answer questions about administration.