Reconstitution converts a lyophilized powder into a solution of known concentration. Use the reconstitution calculator to decide how much diluent to add; this page covers the procedure itself.

Choosing a diluent

  • Bacteriostatic water (sterile water with 0.9% benzyl alcohol) is the standard diluent for vials that will be drawn from more than once, because the preservative inhibits bacterial growth.
  • Sterile water for injection has no preservative and is appropriate for single-use preparations.
  • Sterile 0.9% sodium chloride is used when ionic strength matters to the assay, but some peptides are less soluble in saline than in water.
  • Dilute acetic acid or DMSO are occasionally needed for very hydrophobic or basic sequences. Check the solubility line on the product page and the CoA first.

Procedure

  1. Let the sealed vial and the diluent reach room temperature.
  2. Remove the flip-off cap and wipe the stopper with 70% isopropanol. Allow it to dry.
  3. Draw the calculated volume of diluent into a sterile syringe.
  4. Insert the needle through the stopper and direct the stream down the inside wall of the vial, not onto the cake. Add the diluent slowly.
  5. Withdraw the needle and let the vial stand for a few minutes. Swirl or roll gently until the solution is clear. Do not shake.
  6. Inspect against a dark background. The solution should be clear and free of particles.
  7. Label the vial with the compound, the concentration, the date and the discard date.
  8. Store at 2–8 °C.

Working with small masses

A 2 mg vial reconstituted in 1 mL gives 2 mg/mL; the same vial in 0.5 mL gives 4 mg/mL but is harder to draw accurately from. For dilute working solutions it is usually better to make a concentrated stock and dilute an aliquot than to add a large volume of diluent to the original vial.

This procedure describes laboratory preparation of a research reagent. It is not guidance for administering any substance to humans or animals.