Bac water: questions answered
How long does bac water last?
Unopened, it lasts until the expiry date printed on the label, which is 24 months from the fill date. Once the stopper has been pierced, use it within 28 days, then discard the vial.
How long does bac water last after opening?
28 days from the first time the stopper is pierced, as long as it is kept between 2 and 25 °C. Writing the date on the vial when you first open it makes this easy to track.
Does bac water need to be refrigerated?
No. Store it between 2 and 25 °C, away from light, before and after opening. A fridge falls within that range, so keeping it in the fridge is fine, but it is not required.
Can bac water be frozen?
No. Freezing takes it below the 2 to 25 °C storage range. If a vial has frozen, do not use it.
Can bac water get too warm?
Keep it at or below 25 °C and out of direct light. Do not leave it somewhere that heats up, such as a car or a sunny windowsill.
Can you use bac water after the expiry date?
No. Do not use it after the expiry date on the label, or more than 28 days after the stopper was first pierced, whichever comes first.
Can you use bac water more than once?
Yes. That is what the 0.9% benzyl alcohol is for: it keeps a vial usable for multiple withdrawals for 28 days after it is first opened.
Should bac water be clear?
Yes. It should be clear and colourless with nothing floating in it. If a vial looks cloudy or has particles in it, do not use it.
What is bac water?
Bac water is short for bacteriostatic water: sterile purified water with 0.9% benzyl alcohol added as a preservative. It is also sold as mixing water.
What is bac water made of?
Purified water and benzyl alcohol at 0.9% w/v. Nothing else.
Does bac water have alcohol in it?
It contains 0.9% benzyl alcohol, which is a preservative. It is not the same kind of alcohol as the one in drinks.
Does bacteriostatic water kill bacteria?
Bacteriostatic means it stops bacteria from growing rather than killing them outright. The benzyl alcohol keeps the water from supporting bacterial growth once the stopper has been pierced.
Is bac water the same as sterile water?
No. Both are sterile, but sterile water has no preservative, so a vial is meant for a single use. Bac water contains 0.9% benzyl alcohol, which allows multiple withdrawals over 28 days.
Is bac water the same as saline?
No. Saline is a sodium chloride (salt) solution. Bac water is purified water with benzyl alcohol and contains no salt.
Is bac water the same as deionised or distilled water?
No. Deionised and distilled water are purified, but they are not sterile and contain no preservative. Bac water is sterile filtered, sealed and preserved with 0.9% benzyl alcohol.
What is the difference between bac water and acetic acid 0.6%?
Both are laboratory diluents. Bac water is purified water with a preservative. Acetic acid 0.6% is mildly acidic and is used where a lyophilised reagent specifies an acidic solution. On Labdrop vials, bac water has a blue cap and acetic acid a red one.
Where can I buy bac water in the UK?
Labdrop holds bac water in UK stock. Orders placed before 3pm Monday to Friday are dispatched the same working day. It comes in packs of 1, 10 and 50 vials, and unlabelled in bulk packs of 50, 100 and 200.
Can I buy bac water at Boots or a pharmacy?
Pharmacies do not generally stock it. Labdrop supplies it as a laboratory reagent, for laboratory use only.