Bacteriostatic water is used to dilute or dissolve medications for patient injection. Bacteriostatic Water for Injection is sterile, non-pyrogenic water that contains 0.9% benzyl alcohol (9mg/mL) added as a bacteriostatic preservative, which prevents any contaminating bacteria from growing in the water. In this way, the water has become ‘static’, or relatively unchanging in its bacterial content.T his preparation of sterile water and benzyl alcohol (BnOH) allows repeated withdrawals to be made from a single vial. Once a vial of bacteriostatic water is open, the preservatives will prolong its life, up to 28 days.
The difference between bacteriostatic water and sterile water is that other sterile waters for injection do not contain a bacteriostatic agent. As such, they are single-dose vials and should be discarded after a single use.