Putting the water back
Freeze-drying removes water from a material so it keeps better. Reconstitution reverses that: a liquid is added and the dry solid dissolves to form a solution again.
The ICH stability guideline for biological products uses the term in exactly this sense, for "the reconstitution of powders or lyophilised cakes".
What labs look at afterwards
Stability guidance lists the kinds of things that are checked on a dissolved product:
Why the solution needs its own data
Dry powder slows down the reactions that break peptides apart. In solution those reactions can speed up, so a reconstituted product is a different thing to store. ICH guidance says the stability of a freeze-dried product after reconstitution has to be demonstrated for the conditions and maximum storage period that are stated for it.
Concentration depends on the amount
The concentration of the solution depends on how much material is in the vial and how much liquid is added. The amount of actual peptide can be lower than the powder weight, because freeze-dried peptide also contains water and counter-ions. Research peptides are for laboratory research only and are not approved medicines.
Educational information only. Nothing here is medical advice, dosing guidance or a recommendation to use any substance. Research peptides are not approved medicines and are not for human or animal consumption. Speak to a qualified professional and follow the law where you are.
