Sourcing Guide
Bacteriostatic Water Is Sterile Water
Bacteriostatic water is sterile water that also contains 0.9 % benzyl alcohol to inhibit microbial growth after opening. The sterility is confirmed by USP <71> testing, while the bacteriostatic effect meets USP <51> Category 1B. BAC Water Depot provides both certifications on each lot’s CoA. Therefore, while all bacteriostatic water is sterile, not all sterile water includes a bacteriostatic agent.
- ISO 9001:2015 US facility
- USP <71> sterility tested
- Per-lot Certificate of Analysis
- Same-day US shipping
Direct Answer
BAC Water Depot’s bacteriostatic water is sterile, USP <71>‑tested research‑grade water containing 0.9 % benzyl alcohol. Unopened vials store at controlled room temperature 15–30 °C, no refrigeration, and once punctured refrigerate at 2–8 °C and discard after 28 days.
What USP tests confirm that bacteriostatic water is sterile?
Each lot of BAC Water Depot’s bacteriostatic water undergoes USP <71> sterility testing by membrane filtration, which requires no microbial growth after a 14‑day incubation period. The test is performed by an independent third‑party laboratory and the result appears on the lot’s Certificate of Analysis, accessible via a QR code on the vial. Failure to meet USP <71> results in the lot being rejected and re‑processed, ensuring only sterile product reaches the researcher.
In addition to USP <71>, the product is screened for bacterial endotoxin using USP <85> LAL assay, with a specification of ≤ 0.25 EU/mL. This dual‑testing approach catches both viable organisms and pyrogenic contaminants. A common failure mode is a false‑positive endotoxin result caused by contaminated filtration equipment; the independent lab repeats the assay to verify before releasing the lot.
How is the benzyl alcohol concentration verified in each vial?
BAC Water Depot specifies benzyl alcohol at 0.9 % ± 5 % by weight, verified with HPLC‑UV analysis on every production batch. The HPLC method quantifies the alcohol peak against a calibrated standard curve, and the net content result is listed on the Certificate of Analysis. If the measured concentration falls outside the 0.855–0.945 % range, the batch is flagged and the vials are quarantined until corrective action restores compliance.
A typical source of deviation is solvent evaporation during storage, which can artificially raise the measured percentage. Because the vials are sealed with tamper‑evident closures and stored at 15–30 °C, evaporation is minimized. Researchers should inspect the closure integrity; a compromised seal can lead to concentration drift and affect the bacteriostatic effectiveness defined by USP <51> Category 1B.
What are the packaging and container integrity specifications for the vials?
The product is supplied in 10 mL Type I borosilicate multi‑dose vials, chosen for chemical inertness and low leachability. Container integrity is confirmed per USP <1207> by a helium leak test, ensuring the closure maintains a pressure differential of less than 0.02 in Hg. The CoA records the leak test result, and any vial failing this test is excluded from the shipment. This specification prevents ingress of atmospheric microbes that could compromise sterility after the initial USP <71> test.
Subvisible particulate testing follows USP <788>, with a limit of ≤ 10 particles ≥ 10 µm per vial. Particulate formation can occur if the glass surface is scratched during handling, creating nucleation sites for particles. The manufacturing process includes a visual inspection step to reject any vial with surface defects. Researchers should handle vials with powder‑free gloves to avoid introducing particles that could invalidate the USP <788> specification.
Key Specification Comparison for BAC Water Depot Bacteriostatic Water
| Specification | USP Reference | Accepted Limit/Value |
|---|---|---|
| Sterility | USP <71> | No growth after 14‑day membrane filtration |
| Endotoxin | USP <85> | ≤ 0.25 EU/mL (LAL assay) |
| Benzyl Alcohol | Identity/HPLC‑UV | 0.9 % ± 5 % |
| Bacteriostatic Effectiveness | USP <51> | Category 1B |
| Container Integrity | USP <1207> | Leak ≤ 0.02 in Hg |
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 on a QR‑linked Certificate of Analysis.
- The product contains 0.9 % benzyl alcohol, verified by HPLC‑UV with a ± 5 % tolerance.
- Unopened vials store at controlled room temperature 15–30 °C, no refrigeration, and no cold‑chain shipping.
- Orders placed before 2:00 PM CT Monday‑Friday ship the same business day from Dallas, TX.
Frequently Asked Questions
Is bacteriostatic water the same as sterile water?
Bacteriostatic water is sterile water that also contains 0.9 % benzyl alcohol to inhibit microbial growth after opening. The sterility is confirmed by USP <71> testing, while the bacteriostatic effect meets USP <51> Category 1B. BAC Water Depot provides both certifications on each lot’s CoA. Therefore, while all bacteriostatic water is sterile, not all sterile water includes a bacteriostatic agent.
How long can I keep bacteriostatic water after I puncture the vial?
Once a BAC Water Depot vial is punctured, it must be refrigerated at 2–8 °C and used within 28 days. After that period the benzyl alcohol can lose effectiveness, and the USP <71> sterility guarantee no longer applies. The label and the Certificate of Analysis both state this 28‑day discard rule. Discarding after 28 days prevents potential microbial contamination that the bacteriostatic agent can no longer control.
What is the price per vial for bulk purchases?
BAC Water Depot offers tiered pricing: 25–49 vials cost $7.49 each, 50–149 vials $6.99 each, 150–499 vials $6.74 each, and 500 + vials $6.49 each. Single‑vial purchases are $9.99. Prices include the cost of the 10 mL Type I borosilicate vial and the 0.9 % benzyl alcohol formulation. Shipping is free for orders over $250, which covers up to 100 vials, and same‑day dispatch applies to orders placed before 2:00 PM CT on business days.
Can I rely on the Certificate of Analysis for each lot?
Yes. Every lot of BAC Water Depot bacteriostatic water is accompanied by a Certificate of Analysis generated by an independent third‑party laboratory. The CoA lists USP <71> sterility results, USP <85> endotoxin levels, benzyl alcohol content, pH, subvisible particulates, and container integrity. The QR code on each vial links directly to the CoA at bacwaterdepot.com/coa/<lot-number>, providing transparent, verifiable data for each purchase.
What are the recommended storage conditions before opening the vial?
Unopened vials should be stored at controlled room temperature between 15 °C and 30 °C (59 °F–86 °F), away from direct sunlight. No refrigeration or cold‑chain shipping is required. The label and CoA both specify these conditions, ensuring the benzyl alcohol remains at the intended 0.9 % concentration and the sterility remains intact until the vial is punctured.
How is microbial DNA contamination checked?
BAC Water Depot employs a validated PCR assay on each lot to detect any microbial DNA. The assay’s detection limit is below 10 CFU/mL, and a result of “no detectable microbial DNA” is recorded on the Certificate of Analysis. If DNA is detected, the lot is rejected and re‑tested until it meets the zero‑detectable standard, providing an additional layer of assurance beyond culture‑based sterility testing.
What USP chapters are relevant to the quality testing of bacteriostatic water?
Key USP chapters for BAC Water Depot’s product include USP <71> for sterility, USP <85> for bacterial endotoxin (LAL assay), USP <51> for bacteriostatic effectiveness, USP <788> for subvisible particulates, USP <791> for pH, and USP <1207> for container integrity. Each of these tests is performed on every lot and the results are documented on the lot’s Certificate of Analysis, giving researchers a complete view of compliance with recognized pharmacopeial standards.
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