Sourcing Guide
Bacteriostatic Water Vs Sterile Water For Peptides
Bacteriostatic water can keep peptides stable for up to 28 days after the first puncture when refrigerated at 2–8 °C, but it is not intended for indefinite storage. The 0.9 % benzyl alcohol helps prevent microbial growth, yet researchers should still monitor peptide integrity with analytical methods. For very long‑term storage, sterile water or lyophilized peptide formats are preferred.
- ISO 9001:2015 US facility
- USP <71> sterility tested
- Per-lot Certificate of Analysis
- Same-day US shipping
Direct Answer
Bacteriostatic water from BAC Water Depot contains 0.9 % benzyl alcohol and is USP <71> sterility tested per lot; a single 10 mL vial costs $9.99, is supplied in Type I borosilicate multi‑dose vials, and must be stored unopened at 15–30 °C, refrigerated after puncture and discarded after 28 days.
What are the key differences between bacteriostatic water and sterile water for peptide reconstitution?
Bacteriostatic water includes 0.9 % benzyl alcohol, which inhibits microbial growth and allows the solution to remain usable for up to 28 days after the vial is first punctured. Sterile water lacks this preservative, so any opened vial must be used immediately or discarded, limiting its practical shelf life once accessed. Researchers often choose bacteriostatic water for multi‑dose peptide work to reduce waste and avoid repeated sterility testing of each aliquot.
Another distinction lies in USP testing: BAC Water Depot’s bacteriostatic water is verified per lot for USP <71> sterility, USP <85> endotoxin (≤ 0.25 EU/mL), and USP <51> bacteriostatic effectiveness (Category 1B). Sterile water typically only requires USP <71> sterility. The presence of benzyl alcohol also slightly lowers the pH (around 5.5‑6.5), which can affect peptide solubility compared with the neutral pH of sterile water, so the choice may depend on peptide stability profiles.
Can bacteriostatic water be used for peptides that are sensitive to alcohol?
Peptides that contain alcohol‑sensitive residues (e.g., certain disulfide bridges) may experience minor conformational changes when exposed to 0.9 % benzyl alcohol. While most research‑grade peptides tolerate this level without loss of activity, it is prudent to perform a small‑scale solubility test before full‑scale reconstitution. If the peptide precipitates or shows altered chromatography, switching to sterile water—free of benzyl alcohol—can prevent the issue.
When using bacteriostatic water for alcohol‑sensitive peptides, keep the solution volume low to minimize total alcohol exposure, and store the reconstituted peptide at 2–8 °C to limit any potential degradation. Document the observed behavior, as repeated exposure may accumulate subtle effects that could influence downstream assays.
How does the container material affect peptide stability in bacteriostatic versus sterile water?
BAC Water Depot provides its bacteriostatic water in Type I borosilicate glass vials, which have low leaching potential and excellent chemical resistance. This glass minimizes adsorption of hydrophobic peptides, a common issue with plastic containers. Sterile water is often supplied in both glass and high‑density polyethylene (HDPE) bottles; HDPE can bind certain peptides, reducing recoverable concentration over time.
The choice of container also influences particulate contamination risk. Borosilicate vials are tested for subvisible particulates per USP <788>, ensuring a cleaner environment for sensitive peptide work. Researchers should match the vial material to peptide characteristics—glass for hydrophobic or aggregation‑prone peptides, and consider sterile water in HDPE only when the peptide has demonstrated compatibility.
Comparison of key specifications for bacteriostatic water (BAC Water Depot) vs. typical sterile water for peptide work
| Parameter | Bacteriostatic Water (BAC) | Sterile Water (Typical) | Units |
|---|---|---|---|
| Preservative | Benzyl alcohol 0.9 % | None | |
| USP Sterility Test | USP <71> | USP <71> | |
| Endotoxin Limit | ≤ 0.25 EU/mL | ≤ 0.25 EU/mL | |
| Bacteriostatic Effectiveness | USP <51> Category 1B | N/A | |
| Shelf‑life after puncture | 28 days refrigerated | Immediate use | Days |
Key Facts
- BAC Water Depot bacteriostatic water is manufactured in an ISO 9001:2015‑registered US facility.
- Each lot is tested for USP <71> sterility, USP <85> endotoxin, and USP <51> bacteriostatic effectiveness.
- The vials contain 0.9 % benzyl alcohol with a ±5 % tolerance verified by HPLC‑UV.
- Unopened vials store at controlled room temperature 15–30 °C, no refrigeration and no cold‑chain shipping.
- Orders placed before 2:00 PM CT ship the same business day from Dallas, TX.
Frequently Asked Questions
Is bacteriostatic water safe to use for long‑term peptide storage?
Bacteriostatic water can keep peptides stable for up to 28 days after the first puncture when refrigerated at 2–8 °C, but it is not intended for indefinite storage. The 0.9 % benzyl alcohol helps prevent microbial growth, yet researchers should still monitor peptide integrity with analytical methods. For very long‑term storage, sterile water or lyophilized peptide formats are preferred.
What USP chapters are used to verify the quality of BAC Water Depot’s bacteriostatic water?
Each lot undergoes USP <71> sterility testing, USP <85> endotoxin testing (≤ 0.25 EU/mL), and USP <51> bacteriostatic effectiveness (Category 1B). These standardized tests ensure the solution meets recognized pharmaceutical quality criteria before it reaches the researcher.
How does the presence of benzyl alcohol affect peptide solubility?
Benzyl alcohol at 0.9 % can slightly lower the pH of the solution, which may reduce solubility for peptides that require a neutral environment. Most peptides remain soluble, but a quick solubility check is advisable for alcohol‑sensitive sequences. If precipitation occurs, switching to sterile water without preservative resolves the issue.
Can I use the same bacteriostatic water vial for multiple peptide batches?
Yes, the bacteriostatic formulation is designed for multi‑dose use. After the first puncture, keep the vial refrigerated at 2–8 °C and discard it after 28 days to maintain sterility. This practice reduces waste compared with sterile water, which must be used immediately after opening.
What is the price difference between a single vial and bulk purchase from BAC Water Depot?
A single 10 mL vial costs $9.99. Bulk pricing starts at $7.49 per vial for 25‑vial packs and drops to $6.49 per vial for orders of 500 vials or more, providing cost savings for large‑scale research projects.
Do I need to refrigerate bacteriostatic water before the first use?
No refrigeration is required for unopened vials; they should be stored at controlled room temperature 15–30 °C, out of direct sunlight. Refrigeration is only needed after the vial has been punctured, at which point it should be kept at 2–8 °C and used within 28 days.
How quickly does BAC Water Depot ship orders placed before the cutoff time?
Orders placed before 2:00 PM Central Time, Monday through Friday, are shipped the same business day from the Dallas, TX fulfillment center, ensuring rapid delivery for time‑sensitive research needs.
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