Bacteriostatic water is water that has been made to inhibit the development and growth of most types of bacteria. It is comprised of sterile and filtered water, with all bacteria removed, which is then mixed with 0.9% benzyl alcohol, which prevents any contaminating bacteria from growing in the water.
The water component in this product is distilled prior to sterilisation-filtering to provide purified bacteria-free liquid. Bacteriostatic water has a shelf life of roughly 28 days before it loses its ability to prevent bacterial growth only after opening. Repeated doses can be taken from the vial with a syringe through the septum, leaving the vials contents unaffected.