Quality Assurance
USP <71> Sterility Testing for Bacteriostatic Water — What It Means
USP <71> is the United States Pharmacopeia chapter that defines the sterility test for injectable solutions. It requires that a sample be filtered and incubated in two growth media for 14 days to confirm the absence of viable microorganisms. An independent third-party laboratory runs this test on every BAC Water Depot production lot, and the result is documented on that lot’s Certificate of Analysis. Passing USP <71> indicates the water meets the regulatory sterility standard for research use.
- ISO 9001:2015 US facility
- USP <71> sterility tested
- Per-lot Certificate of Analysis
- Same-day US shipping
Direct Answer
USP <71> sterility testing verifies that each lot of BAC Water Depot bacteriostatic water contains no viable microorganisms, meeting the United States Pharmacopeia requirement for injectable solutions. Each 10 mL vial is priced at $9.99 and every lot is tested by an independent third-party laboratory with a per-lot Certificate of Analysis.
How is USP <71> sterility testing performed on bacteriostatic water?
USP <71> requires a membrane filtration method where 100 mL of the water sample is passed through a 0.45 µm pore-size filter, then the filter is incubated in two separate media: Fluid Thioglycollate Medium at 30 °C for 14 days and Tryptic Soy Broth at 20-25 °C for 14 days. For BAC Water Depot lots, an independent laboratory performs this test and reports the outcome on the Certificate of Analysis; a negative result—no growth in the test or media controls—is recorded before the lot is released. A common failure mode in sterility testing is filter breach or improper aseptic technique, which can introduce contaminants that proliferate during the 14-day incubation—one reason the test includes media controls. Any lot that shows growth is not released, and the vials themselves are Type I borosilicate glass with a tamper-evident closure, both of which are also checked on the Certificate of Analysis.
What storage conditions preserve sterility of bacteriostatic water after USP testing?
Sterility is established at release; storage afterwards is about keeping the sealed system intact. Unopened BAC Water Depot vials are stored at controlled room temperature, 15–30 °C (59–86 °F), out of direct sunlight—no refrigeration and no cold-chain shipping are required, and the expiration date is printed on the label and the Certificate of Analysis. The 0.9 % benzyl alcohol is a bacteriostatic preservative for a multi-dose vial: it suppresses growth of organisms introduced after the seal is first punctured, which is why the label directs that a punctured vial be refrigerated at 2–8 °C and discarded after 28 days. Before any use, inspect the solution—it should be clear, colorless, and free of visible particulates—and discard any vial that is cloudy or past its expiration date.
Can USP <71> sterility testing detect endotoxin contamination in bacteriostatic water?
USP <71> sterility testing is designed to detect viable microorganisms, not endotoxins, which are heat-stable lipopolysaccharides from Gram-negative bacteria. To assess endotoxin levels, a separate test such as the Limulus Amebocyte Lysate (LAL) assay (USP <85>) is required. Each BAC Water Depot lot is LAL-tested by the independent laboratory against a specification of ≤ 0.25 EU/mL, and the measured result is printed on the Certificate of Analysis. A failure to perform endotoxin testing can lead to pyrogenic reactions even when sterility is confirmed. In practice, a lot that passes USP <71> but exceeds the endotoxin threshold must be re-processed or discarded. BAC Water Depot’s dual-testing approach—USP <71> for sterility and USP <85> for endotoxin—provides a comprehensive safety profile for research-grade applications.
Parameters reported on a BAC Water Depot per-lot Certificate of Analysis
| Parameter | Specification | Test Method |
|---|---|---|
| Sterility | No microbial growth in 14-day membrane filtration test | USP <71> |
| Bacterial endotoxin | ≤ 0.25 EU/mL | USP <85> · LAL |
| Microbial analysis | No detectable microbial DNA | Validated PCR-based assay |
| Bacteriostatic effectiveness | USP <51> Category 1B criteria met | USP <51> |
| Benzyl alcohol (net content) | 0.90 % ± 5 % | HPLC-UV |
| Storage (unopened) | Controlled room temperature 15–30 °C (59–86 °F) | Label / CoA |
Key Facts
- BAC Water Depot manufactures bacteriostatic water in a US facility certified to ISO 9001:2015.
- Each lot is USP <71> sterility tested using the membrane filtration method with 14-day dual-media incubation.
- Independent third-party laboratory results — sterility, endotoxin, microbial PCR, bacteriostatic effectiveness, benzyl alcohol content — are published on a per-lot Certificate of Analysis.
- The product contains 0.9 % benzyl alcohol as a bacteriostatic preservative.
- Orders placed before 2:00 PM CT ship the same day from a US fulfillment center.
Frequently Asked Questions
What does USP <71> mean for bacteriostatic water?
USP <71> is the United States Pharmacopeia chapter that defines the sterility test for injectable solutions. It requires that a sample be filtered and incubated in two growth media for 14 days to confirm the absence of viable microorganisms. An independent third-party laboratory runs this test on every BAC Water Depot production lot, and the result is documented on that lot’s Certificate of Analysis. Passing USP <71> indicates the water meets the regulatory sterility standard for research use.
How often is bacteriostatic water re-tested after the initial USP <71> test?
USP <71> testing is performed once per production lot before release; the test is not repeated on individual vials after distribution. Each Certificate of Analysis lists the lot’s release date, retest date, and expiration date, so the testing window for any vial is visible on the report itself. If a customer reports a problem with a vial, the lot can be re-examined under the same USP <71> protocol to investigate the cause.
Is the 0.9 % benzyl alcohol concentration verified for each lot?
Yes. Benzyl alcohol net content is measured on each lot by HPLC-UV against a specification of 0.90 % ± 5 %, and identity is confirmed against a benzyl alcohol reference. Both results appear on the Certificate of Analysis alongside the USP <71> sterility result. Consistent concentration ensures the preservative effect is maintained throughout the product’s shelf life.
Can I use BAC Water Depot bacteriostatic water for human injections?
No. BAC Water Depot bacteriostatic water is sold for research and laboratory use only. It is not for human or veterinary use, and nothing on the Certificate of Analysis changes that: USP <71> sterility and USP <85> endotoxin results describe the lot; they are not a clearance for any use outside the laboratory.
Does bacteriostatic water need to be refrigerated during shipping?
No. Unopened vials are stored at controlled room temperature, 15–30 °C (59–86 °F), which is the storage condition printed on each lot’s Certificate of Analysis, so standard ground and overnight shipping without cold packs is appropriate. Keep vials out of direct sunlight. Once a vial has been punctured, refrigerate it at 2–8 °C and discard it after 28 days.
How do I verify the Certificate of Analysis for a specific lot?
Each vial carries a scannable QR code that links directly to bacwaterdepot.com/coa/[lot-number]. The online page displays the USP <71> sterility result, benzyl alcohol concentration, endotoxin level, and the independent laboratory results for that lot. The report can be saved for record-keeping.
What is the price advantage of buying BAC Water Depot in bulk?
A single 10 mL vial costs $9.99. Purchasing 25 vials reduces the unit price to $7.49, 50 vials to $6.99, 150 vials to $6.74, and 500 vials or more to $6.49 per vial. All bulk orders include the same USP <71> sterility testing and per-lot Certificate of Analysis, and they qualify for same-day US shipping when ordered before 2:00 PM CT.
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