Hospira bac water is bacteriostatic water for injection with 0.9% benzyl alcohol. Learn what it's used for, how to store it, and how to spot fake vials.
Hospira bac water is Bacteriostatic Water for Injection, USP — sterile water that contains 0.9% benzyl alcohol as a preservative and is supplied by Hospira, a Pfizer company, in multiple-dose vials. It is meant to dilute or dissolve compatible injectable drugs, not to be injected on its own. In the United States it is a prescription product, which is one reason unverified online listings deserve a second look.
What "Hospira Bac Water" Actually Means
"Bac water" is shorthand for bacteriostatic water. The word "bacteriostatic" describes the preservative, not an ability to sterilize a solution that has already been contaminated. The 0.9% benzyl alcohol simply slows bacterial growth that could occur when a needle punctures a stopper more than once.
- Manufacturer: Hospira, which Pfizer acquired in 2015, so current labels and packaging reflect Pfizer-affiliated branding.
- Composition: Sterile, non-pyrogenic water for injection plus 0.9% (9 mg/mL) benzyl alcohol.
- Container: Multiple-dose vials built for repeated withdrawals.
- Regulatory status: A prescription (Rx-only) drug product in the United States, not an over-the-counter supply.
Because the USP monograph for Bacteriostatic Water for Injection is publicly defined, several manufacturers produce an equivalent item. "Hospira bac water" names a brand, not a unique formulation.
What Bac Water Is Used For
Hospira's labeled purpose is to dilute or dissolve drugs intended for intramuscular, intravenous, or subcutaneous injection. Pharmacies that stock clinical and compounding diluents keep bac water for injection on the same shelf as sterile water and sterile saline.
The preservative is what makes a multiple-dose vial practical. Staff can draw from the same vial several times instead of opening a fresh single-use container for every dose, which reduces waste and cost in busy settings.
Reconstitution in research and hobbyist settings
Outside clinical pharmacy, the same product is widely discussed as bac water for peptides, since it is the diluent most often used to reconstitute lyophilized peptide powders. That use is informal and is not an FDA-approved indication, and benzyl alcohol can degrade or interact with certain compounds.
Where bac water should not be used
- As a standalone injection or for wound irrigation.
- In newborns and premature infants — benzyl alcohol exposure has caused serious, sometimes fatal, toxicity in this group.
- For routes such as intrathecal or epidural administration.
- With any drug that is chemically incompatible with benzyl alcohol.
Bacteriostatic Water vs. Sterile Water and Saline
Bacteriostatic water and sterile water for injection are not interchangeable in every situation. The table below covers the differences that matter most.
| Product | Contains | Preservative | Typical use |
|---|---|---|---|
| Bacteriostatic water for injection (Hospira bac water) | Sterile water, 0.9% benzyl alcohol | Yes | Diluting or dissolving compatible drugs in a multi-dose vial |
| Sterile water for injection | Sterile water only | No | Single-use dilution; discard after opening |
| Bacteriostatic 0.9% sodium chloride | Sterile saline, 0.9% benzyl alcohol | Yes | Diluting compatible drugs that require a saline base |
| Sterile 0.9% sodium chloride | Sterile saline only | No | IV fluids, flushes, single-use dilution |
Plain sterile water has no preservative, so an opened container is generally treated as single-use. Bacteriostatic saline is a separate product: normal saline with benzyl alcohol added.
Sizes, Packaging, and Availability
Hospira's catalog presentation has historically been a 30 mL multiple-dose vial, so the most common single-vial order in clinical and wholesale channels is bac water 30ml.
- Single vials: The standard unit for pharmacies, clinics, and individual buyers with a valid prescription.
- Case quantities: Institutional distributors and some resellers list a hospira bacteriostatic water 25 pack, which is a case count rather than a different product.
- Smaller formats: If you are searching for hospira bac water 10ml or a 3 mL vial, verify the seller carefully — smaller fills are frequently offered by other manufacturers, compounders, or secondary-market resellers rather than as standard Hospira catalog items.
Supply has been uneven in recent years. Pfizer has periodically listed bacteriostatic water for injection as backordered or on allocation, which pushes buyers toward secondary marketplaces where quality controls are weaker.
Storage and Handling
Bacteriostatic water for injection should be stored at controlled room temperature, roughly 20 °C to 25 °C (68 °F to 77 °F), and should not be frozen. Freezing can damage the container and compromise the preservative system.
- Inspect the vial before each use; do not use a solution that is cloudy, discolored, or contains particles.
- Swab the stopper with an appropriate disinfectant and let it dry before drawing.
- Note the date the vial was first entered and follow the manufacturer's in-use limits or your facility's policy.
- Discard the vial when the labeled beyond-use period ends, even if liquid remains.
Safety, Legal Status, and Gray-Market Risk
Bacteriostatic water for injection is a prescription drug in the United States, not a general-purpose supply. Buying it outside a licensed pharmacy or authorized distributor means you cannot confirm its identity, sterility, fill volume, or storage history.
No research-chemical listing can guarantee that a vial labeled Hospira bac water is genuine, sterile, or handled correctly. Common problems in that market include relabeled vials from unrelated manufacturers, underfilled containers, and water that was never sterile-filtered in the first place.
Benzyl alcohol is the reason bacteriostatic water is not used in newborns, and it is also why the product is not appropriate for every drug or every route of administration. Anyone reconstituting a medication or research compound should confirm compatibility with a licensed pharmacist or physician before use. This article is informational only and does not replace professional medical advice.
Frequently Asked Questions
Is Hospira bac water the same as bacteriostatic water?
Yes. Hospira bac water is the common shorthand for Hospira's Bacteriostatic Water for Injection, USP, which is sterile water containing 0.9% benzyl alcohol as a preservative. Several other manufacturers make an equivalent product under the same USP monograph, so the formulation is not unique to Hospira.
Can you use Hospira bac water to reconstitute peptides?
Bacteriostatic water is the diluent most often used for reconstituting lyophilized peptide powders in research and hobbyist settings, but that is not an FDA-approved indication. Benzyl alcohol can degrade or interact with certain peptides, and bacterial growth is only slowed, not stopped. Talk to a pharmacist or physician about compatibility before reconstituting anything.
Why is Hospira bacteriostatic water sometimes hard to find?
Pfizer has periodically listed bacteriostatic water for injection as backordered or on allocation, so availability varies by distributor and month. When supply tightens, secondary-market listings appear with little or no quality assurance. A licensed pharmacy or authorized wholesaler is the only way to confirm authenticity and proper storage.
This page provides educational research information and does not replace medical advice, diagnosis, or treatment.