Glossary
Bacteriostatic water
Also written BAC water, bac water
Sterile water containing a small amount of benzyl alcohol, which stops bacteria multiplying and allows a vial to be used more than once.
The benzyl alcohol is what distinguishes it from plain sterile water. Because it prevents bacterial growth, a vial mixed with bacteriostatic water can be entered repeatedly over a period of weeks rather than being discarded after one use.
It is not the same as sterile water for injection, and the two are not interchangeable for a multi-use vial.
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