Bacteriostatic Water

Sterile water containing 0.9% benzyl alcohol. The benzyl alcohol is a preservative that inhibits bacterial growth, so a vial can be entered more than once. Without the preservative, the product is simply sterile water.

Both are sterile. Bacteriostatic water contains 0.9% benzyl alcohol, which inhibits bacterial growth and allows multiple entries into the same vial. Sterile water contains no preservative and is meant for single use; once opened, it should be discarded. Some peptides and assays are not compatible with benzyl alcohol, so the right diluent depends on the experiment.

It is one of several common diluents for lyophilized peptides. The preservative allows a reconstituted vial to be entered repeatedly while limiting bacterial growth, which suits work that draws from the same vial over several days. Other protocols call for sterile water, saline or a dilute acid, depending on the peptide's solubility and the assay.

Yes. An unopened vial is good until the expiration date on its label. Once the stopper has been punctured, the usual practice is to discard the vial after 28 days, because the preservative cannot fully prevent contamination indefinitely. Discard it sooner if it looks cloudy or contains particles.

No. Bacteriostatic water is normally stored at controlled room temperature, about 20–25 °C, away from light. Refrigeration does it no harm, but it is not required.

Let the sealed vial reach room temperature so moisture does not condense inside. Disinfect the stopper with alcohol, then add the chosen sterile diluent slowly down the inside wall of the vial rather than directly onto the powder. Swirl or roll gently until dissolved; do not shake. The resulting concentration is the peptide's labeled mass divided by the volume added. Label the vial with the date and concentration and store it refrigerated.

No. Bacteriostatic water is sterile water with 0.9% benzyl alcohol and no salt. Normal saline is sterile 0.9% sodium chloride in water, usually without a preservative. Saline's salt content makes it isotonic, which some cell-based protocols require, but salt can lower the solubility of some peptides. The right diluent depends on the peptide's solubility and the assay.

Both contain 0.9% benzyl alcohol as a preservative and both allow multiple entries into the vial. Bacteriostatic sodium chloride is 0.9% saline with that preservative, while bacteriostatic water contains no salt. The choice depends on whether the protocol calls for an isotonic, salt-containing diluent and whether the peptide stays soluble in salt.

Distilled and deionized water are purified water, but they are not packaged as sterile products and contain no preservative, so neither is bacteriostatic. Bacteriostatic water is sterile, sealed in a stoppered vial, and contains 0.9% benzyl alcohol to inhibit bacterial growth after the vial is first entered. For reconstituting peptides intended for biological assays, laboratories use sterile diluents rather than water from an opened bottle.

"Reconstitution solution" is a general term for any liquid used to dissolve a powder, and bacteriostatic water is one of them. Others include sterile water, saline, bacteriostatic saline and dilute acetic acid, which is used for some peptides that dissolve poorly in water. A product labeled only "reconstitution solution" should state its composition; if it does not, you cannot know whether it contains a preservative.

Two ingredients: sterile water and benzyl alcohol at 0.9% (9 mg per mL). Benzyl alcohol is an aromatic alcohol used as a preservative; it is not ethanol, the alcohol in drinks. The solution is prepared under sterile manufacturing conditions and sealed in stoppered vials.

Not reliably. Bacteriostatic means it inhibits bacterial growth and reproduction, as opposed to bactericidal, which means killing bacteria outright. The 0.9% benzyl alcohol keeps small numbers of bacteria introduced when the vial is entered from multiplying, but it does not sterilize contaminated material and is not active against every microorganism. Aseptic technique is still required.

Not to the same standard outside a sterile manufacturing facility. Commercial bacteriostatic water is produced under sterile conditions, with a controlled benzyl alcohol content, sterility and endotoxin testing, and sealed vials. Mixing benzyl alcohol into water yourself gives neither verified sterility nor a verified preservative concentration, and it can introduce endotoxins that interfere with biological assays. Buy it sealed from a supplier.

Yes, within limits; that is what the preservative is for. A vial of bacteriostatic water is a multiple-entry vial: the 0.9% benzyl alcohol limits bacterial growth between entries. Disinfect the stopper before each entry, use sterile technique, and follow the usual practice of discarding the vial 28 days after the stopper is first punctured, or sooner if the water looks cloudy or contains particles.

It is not recommended. Bacteriostatic water is meant to be stored at controlled room temperature, about 20–25 °C. Freezing can crack the glass vial or loosen the stopper's seal as the water expands, which compromises sterility. Discard a vial that has frozen, especially if the glass, stopper or seal looks damaged.

Avoid it. Bacteriostatic water is labeled for storage at controlled room temperature, about 20–25 °C, and brief excursions between 15 and 30 °C are generally acceptable. Prolonged heat, such as in a parked car, increases evaporation and pressure inside the vial and stresses the stopper seal. Replace a vial that has been badly overheated, looks cloudy or has a damaged seal.

Two separate limits apply. The expiration date on a sealed vial reflects the manufacturer's stability data for the solution, preservative and container. Once the stopper is punctured, the 28-day discard practice applies, because each entry can introduce microorganisms and the preservative can only hold them back for a limited time. Discard it sooner if it looks cloudy or contains particles.

Every lot is documented with a Certificate of Analysis. The certificate for the current lot is published when the lot is received; past certificates are in the COA library, and we will send a lot's COA on request.

Bacteriostatic Water is supplied as a sealed vial of solution: 10ml. In stock and dispatched in 1–2 business days. Quantity pricing applies automatically at 5+ and 10+ vials of the same size.

Store sealed at 20–25 °C, protected from light.