What Is Bacteriostatic Water?
Bacteriostatic water, often called BAC water, is sterile Water for reconstitution and preservation of lyophilized research compounds, peptides, and proteins for laboratory study that contains 0.9% benzyl alcohol as a preservative. The preservative inhibits bacterial growth after the vial has been opened, making it suitable for multi-dose laboratory environments where repeated access to the vial is required.
Unlike standard sterile water, bacteriostatic water is designed to remain bacteriostatic after opening because of the preservative. This characteristic makes it different from single-use sterile water products.
What’s Inside BAC Water?
A typical bacteriostatic water formulation contains:
- Sterile Water Base
- 0.9% Benzyl Alcohol
- USP-grade components
- Sterile multi-sampling vial
- Tamper-evident seal
The solution itself is clear, colorless, and free of visible particles.
BAC Water vs Sterile Water
| Feature | BAC Water | Sterile Water |
|---|---|---|
| Preservative | 0.9% Benzyl Alcohol | None |
| Bacteriostatic | Yes | No |
| Multi-sampling vial | Yes | Generally No |
| Sterility | Sterile | Sterile |
| Repeated laboratory access | Designed for it | Single use |
Quality Standards
High-quality bacteriostatic water products are commonly manufactured using:
- USP Type I borosilicate glass
- Sterile filling process
- Quality-controlled manufacturing
- Batch traceability
- Certificate of Analysis
- Tamper-evident packaging
Storage
Manufacturers commonly recommend:
- Store between 20–25°C (68–77°F)
- Protect from direct sunlight
- Keep vial sealed until needed
- Do not use damaged containers
Frequently Asked Questions
Is bacteriostatic water sterile?
Yes. It is sterile and also contains benzyl alcohol to inhibit bacterial growth.
Does BAC water contain medication?
No. It is simply sterile water with 0.9% benzyl alcohol.
Why is benzyl alcohol added?
It helps inhibit bacterial growth after the vial has been opened.
Conclusion
Bacteriostatic water provides sterile water combined with a preservative that supports multi-dose laboratory handling. Choosing a quality-controlled manufacturer helps ensure product consistency, sterility, and documentation.