Bacteriostatic Water for Injection, USP
What Is BAC Water?
What does bacteriostatic actually mean?
Bacteriostatic means holding bacterial growth in check rather than killing bacteria outright. The distinction matters here: the benzyl alcohol is not sterilizing the vial, it is preventing anything introduced on a needle from multiplying between draws. The water was already sterile when it was sealed.
What is in the vial?
| Specification | Value |
|---|---|
| USP grade | Bacteriostatic Water for Injection, USP |
| Preservative | Benzyl alcohol 0.9% (9 mg/ml) |
| Sterility | Sterile, non-pyrogenic |
| Container | Multiple-dose glass vial |
| Closure | Rubber stopper with aluminum seal and flip-off cap |
| Storage | Refrigerated. Good until the printed expiration date. |
| Not for use in | Neonates |
Sterile water and benzyl alcohol. Nothing else.
What is bac water used for?
It is a diluent. Something supplied as a freeze-dried powder cannot be measured or drawn until it is dissolved, and bac water is what dissolves it. The water contributes nothing beyond being a clean, preserved liquid to put the powder into.
Bac water is not a treatment, a supplement or an active ingredient, and it is supplied for laboratory research use only.
How long does bac water last?
Bac water is good until the expiration date printed on the vial, typically several years from manufacture, when it is kept refrigerated. The benzyl alcohol is what allows the same vial to be drawn from more than once.
How is it different from sterile water and saline?
| Bacteriostatic water | Sterile water | Saline | |
|---|---|---|---|
| Preservative | 0.9% benzyl alcohol | None | None (usually) |
| Contains salt | No | No | Yes, 0.9% sodium chloride |
| Doses | Multiple | One | Varies |
| Use window | the expiration date | Immediate | Varies |
The full comparison is on bac water vs sterile water.
Where do you get it?
Not from a supermarket shelf. It is a prescription product, so it comes from an online supplier, a pharmacy counter, or a licensed distributor. Retailer by retailer, that is covered on where to buy bac water.
Frequently Asked Questions
- What does bac water stand for?
- Bac water is short for bacteriostatic water for injection, USP. Bacteriostatic means it suppresses bacterial growth rather than killing bacteria outright, which is the job of the 0.9% benzyl alcohol it contains.
- What is bac water used for?
- Bac water is used in the laboratory as a diluent, to reconstitute a compound supplied as a powder. Bac water has no activity of its own and is supplied for research use only.
- What grade is bac water?
- Bac water is manufactured to the USP monograph for Bacteriostatic Water for Injection. The material sold here is supplied for laboratory research use only and is not for human or veterinary use.
- What is in bac water?
- Bac water contains sterile water for injection and benzyl alcohol at 0.9%, which is 9 mg per mL. There is nothing else in the vial.
- Why is bac water called multiple-dose?
- It is called multiple-dose because the benzyl alcohol lets the stopper be punctured repeatedly. Vials without a preservative are single-dose and are discarded after one use.
- Can bac water expire?
- Yes, in two ways. Unopened it expires on the date printed on the vial. Once punctured it lasts the expiration date regardless of that date, and the earlier of the two is the one that applies.
Important notices
Bacteriostatic water for injection, USP sold on this site is supplied strictly for laboratory research use only. It is not a drug, not a dietary supplement, and not intended for human or veterinary use, diagnosis, treatment, or the prevention of any condition. It may not be administered to humans or animals. By ordering you confirm you are a qualified buyer purchasing for in vitro research conducted in a controlled laboratory environment.
