Reconstitution

Reconstitution is the step that turns a vial of lyophilised powder into a solution. A measured volume of diluent, almost always bacteriostatic water, is drawn into a syringe, injected slowly into the vial along the inside of the glass, and the vial is left to dissolve without shaking. The peptide is then in solution at a known concentration, and doses can be drawn in syringe units.

The single decision that matters is how much diluent to add. It does not change how much peptide is in the vial; it changes how concentrated the solution is, and therefore how many syringe units correspond to a given amount. A 5 mg vial reconstituted with 1 mL holds 5 mg/mL, so each unit on a U-100 syringe carries 50 µg. Reconstituted with 2 mL it holds 2.5 mg/mL and each unit carries 25 µg. The dosage calculator does this arithmetic, and the dosing-math guide explains it.

Once reconstituted, a vial is a solution with a shelf life measured in weeks, kept refrigerated and never frozen. The reconstitution guide walks through the full procedure with photographs, including aseptic technique.