Sourcing Guide
Bacteriostatic Water Is What
In research settings, bacteriostatic water serves as a sterile diluent for reconstituting lyophilized compounds, maintaining solution sterility during repeated withdrawals. The 0.9 % benzyl alcohol inhibits bacterial growth, allowing multi-dose use over several weeks. BAC Water Depot provides this product with USP <71> sterility certification, ensuring no microbial contamination at the time of release. After a vial is punctured, keep it refrigerated and discard it 28 days after the first puncture.
- ISO 9001:2015 US facility
- USP <71> sterility tested
- Per-lot Certificate of Analysis
- Same-day US shipping
Direct Answer
Bacteriostatic water is a sterile, non‑pyrogenic aqueous solution containing 0.9 % benzyl alcohol that inhibits bacterial growth and is sold for research use only. BAC Water Depot sells 10 mL Type I borosilicate vials at $9.99 each, each lot tested per USP <71> for sterility.
What is the composition of bacteriostatic water and how is it prepared?
Bacteriostatic water consists of purified water with 0.9 % (w/v) benzyl alcohol, which provides a bacteriostatic effect by disrupting bacterial cell membranes. The solution is prepared in a controlled environment using USP‑grade reagents and filtered through a 0.2 µm membrane to ensure sterility. Each lot undergoes independent third‑party verification of benzyl alcohol concentration by HPLC‑UV, confirming the 0.90 % ± 5 % specification. A common failure mode is deviation in benzyl alcohol content, which would cause the lot to be rejected during the CoA review and not released for sale. The final product is aseptically filled into 10 mL Type I borosilicate multi‑dose vials with tamper‑evident closures. USP <791> pH testing ensures the solution remains within the acceptable range (typically 6.0–7.5) to maintain chemical stability. Any vial that shows out‑of‑range pH or visible particulates in USP <788> subvisible particle testing is quarantined and excluded from distribution.
How is bacteriostatic water quality verified before release?
Each production lot receives a full Certificate of Analysis that documents results from multiple validated assays. Sterility is confirmed by USP <71> membrane filtration with a 14‑day incubation showing no microbial growth. Bacterial endotoxin levels are measured by USP <85> LAL testing and must not exceed 0.25 EU/mL. Microbial DNA is screened using a validated PCR assay, and any detectable DNA triggers lot rejection. The bacteriostatic effectiveness is evaluated per USP <51> Category 1B, confirming that the 0.9 % benzyl alcohol maintains inhibition for the defined storage period. Additional tests include container integrity per USP <1207>, ensuring the vial seal remains intact under pressure differentials, and subvisible particulates per USP <788>, which must be ≤ 10 particles ≥ 25 µm per vial. Failure in any of these critical tests—such as a positive PCR result or endotoxin level above the limit—results in the lot being marked non‑conforming and withheld from shipment.
What are the storage and handling requirements for bacteriostatic water after opening?
Unopened vials must be stored at controlled room temperature 15–30 °C, out of direct sunlight, with no refrigeration or cold‑chain shipping required. The expiration date is printed on the label and reproduced on the CoA, and it must be observed to ensure potency. Once a vial is punctured, the recommended practice is to refrigerate the remaining solution at 2–8 °C and discard it after 28 days, as the bacteriostatic effect diminishes over time and microbial contamination risk rises. A frequent handling error is failure to refrigerate after opening, which can lead to bacterial proliferation despite the presence of benzyl alcohol. Additionally, repeated needle insertions can compromise the tamper‑evident closure, allowing particulate ingress; therefore, using a new sterile needle for each withdrawal is essential to maintain the integrity of the sterility barrier.
Key Quality Specifications for BAC Water Depot Bacteriostatic Water (per lot)
| Specification | Test Method | Limit / Result |
|---|---|---|
| Sterility | USP <71> membrane filtration | No growth (14‑day incubation) |
| Endotoxin | USP <85> LAL assay | ≤ 0.25 EU/mL |
| Benzyl Alcohol Content | HPLC‑UV | 0.90 % ± 5 % |
| Bacteriostatic Effectiveness | USP <51> Category 1B | Effective for 28 days at 2–8 °C after opening |
| Subvisible Particles | USP <788> | ≤ 10 particles ≥ 25 µm per vial |
Key Facts
- BAC Water Depot’s bacteriostatic water is manufactured in an ISO 9001:2015‑registered US facility.
- Each lot is tested by an independent third‑party laboratory and the results are posted via a QR‑code linked to the CoA.
- The solution contains benzyl alcohol at 0.9 % (w/v) to provide bacteriostatic activity.
- USP <71> sterility testing requires a 14‑day membrane filtration incubation with no detectable growth.
- Orders placed before 2:00 PM CT Monday‑Friday ship the same business day from Dallas, TX.
Frequently Asked Questions
What is bacteriostatic water used for in research labs?
In research settings, bacteriostatic water serves as a sterile diluent for reconstituting lyophilized compounds, maintaining solution sterility during repeated withdrawals. The 0.9 % benzyl alcohol inhibits bacterial growth, allowing multi-dose use over several weeks. BAC Water Depot provides this product with USP <71> sterility certification, ensuring no microbial contamination at the time of release. After a vial is punctured, keep it refrigerated and discard it 28 days after the first puncture.
How does benzyl alcohol prevent bacterial growth in bacteriostatic water?
Benzyl alcohol disrupts bacterial cell membranes by solubilizing lipids, which halts protein synthesis and leads to cell death at low concentrations. At 0.9 % (w/v), it provides sufficient antimicrobial activity without compromising most protein stability. BAC Water Depot verifies the benzyl alcohol concentration by HPLC‑UV, confirming it meets the 0.90 % ± 5 % specification. The bacteriostatic effect persists for the recommended storage period, but the solution must be refrigerated after opening to maintain efficacy.
Can I use bacteriostatic water for cell culture media preparation?
Bacteriostatic water is generally not recommended for direct cell culture media preparation because the benzyl alcohol can be cytotoxic at the concentrations used. Researchers typically prefer sterile water for injection (SWFI) without preservatives for cell culture work. If a preservative‑free diluent is required, BAC Water Depot also offers sterile water for research, but the bacteriostatic formulation should be limited to applications where the preservative does not interfere with assay outcomes.
What are the packaging options and pricing for BAC Water Depot bacteriostatic water?
BAC Water Depot supplies 10 mL Type I borosilicate multi‑dose vials. A single vial costs $9.99. Bulk pricing reduces the per‑vial cost: 10‑pack at $74.99 ($7.49 each), 25‑pack at $174.99 ($6.99 each), and larger orders (150 vials or more) drop to $6.49 per vial. Free standard shipping is provided on orders over $250, covering up to 100 vials. All orders placed before 2:00 PM CT Monday‑Friday ship the same business day from the Dallas fulfillment center.
How can I verify the quality of a specific lot of bacteriostatic water?
Each vial bears a QR code that links to the lot‑specific Certificate of Analysis on bacwaterdepot.com/coa/<lot-number>. The CoA lists results for USP <71> sterility, USP <85> endotoxin, benzyl alcohol content, PCR‑based microbial DNA screening, and other critical tests. Researchers can scan the code with a smartphone to view the independent laboratory data before use, ensuring traceability and compliance with lab quality standards.
What is the recommended procedure for handling a punctured vial?
After the first puncture, the vial should be capped with its original tamper‑evident closure and stored at 2–8 °C. The solution must be discarded after 28 days, as the bacteriostatic effect diminishes and contamination risk increases. Using a new sterile needle for each withdrawal helps maintain the integrity of the closure and prevents particulate ingress, which can be a common cause of sterility compromise.
Are there any regulatory restrictions on using bacteriostatic water in animal studies?
Bacteriostatic water sold by BAC Water Depot is labeled for research‑use‑only and is not intended for clinical, veterinary, or human administration. Researchers must obtain appropriate Institutional Animal Care and Use Committee (IACUC) approvals for any animal work and ensure that the preservative (benzyl alcohol) does not interfere with study endpoints. The product’s USP <71> sterility and endotoxin testing provide confidence for laboratory use, but compliance with study‑specific protocols remains the investigator’s responsibility.
Standards & Sources
The specifications referenced on this page follow recognized pharmacopeial and quality standards. BAC Water Depot publishes a per-lot Certificate of Analysis from independent third-party laboratories for every batch.
- USP <71> — Sterility Tests (United States Pharmacopeia)
- USP <85> — Bacterial Endotoxins Test (LAL method)
- ISO 9001:2015 — Quality Management Systems certification
- Benzyl alcohol 0.9% w/v — the bacteriostatic preservative standard for multi-dose vials