Steri-Pep BAC Water 30ml
A 30ml multiple-dose vial of bacteriostatic water for injection, USP, preserved with 0.9% benzyl alcohol so it can be drawn from repeatedly.
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Same business day dispatch before 3pm. Flat $7.95 shipping, plain packaging.
What is bac water?
Bac water is bacteriostatic water for injection, USP: sterile water with 0.9% benzyl alcohol added as a preservative. That preservative is the entire difference between it and every other water in a vial. It suppresses bacterial growth after the stopper has been punctured, which is what lets one vial be drawn from many times repeatedly instead of being thrown away after a single use.
It is a diluent. Its job is to dissolve or dilute something else, and it has no effect of its own.
How does bac water differ from sterile water?
| Bacteriostatic water | Sterile water | |
|---|---|---|
| Preservative | 0.9% benzyl alcohol | None |
| Doses per vial | Multiple | One |
| Use window after opening | the expiration date | Immediately, then discard |
| Typical use | Reconstituting a vial used over time | A single preparation |
Pick sterile water when whatever you are mixing will be used at once, and bacteriostatic water when the vial has to last. Full comparison on the bac water vs sterile water page.
Why does the benzyl alcohol preservative matter?
Every time a needle goes through a rubber stopper it carries the possibility of introducing organisms. In an unpreserved vial there is nothing to stop what gets in from multiplying, which is why single-dose vials are single-dose. Benzyl alcohol at 9 mg per mL holds that growth down, and the expiration date is the window that concentration is rated for.
Benzyl alcohol is also why the manufacturer prints a neonate restriction on the label. The material sold here is supplied for laboratory research use only in any case.
What are the full specifications?
| Specification | Value |
|---|---|
| USP grade | Bacteriostatic Water for Injection, USP |
| Preservative | Benzyl alcohol 0.9% (9 mg/ml) |
| Sterility | Sterile, non-pyrogenic |
| Container | Multiple-dose glass vial |
| Closure | Rubber stopper with aluminum seal and flip-off cap |
| Storage | Refrigerated. Good until the printed expiration date. |
| Not for use in | Neonates |
Volume in this vial is 30 mL. Every figure above comes from the USP monograph and the manufacturer's label.
How do you use bac water to reconstitute a peptide?
- Let both vials come to room temperature and wipe each stopper with an alcohol prep pad.
- Draw your chosen volume of bacteriostatic water into a syringe.
- Angle the needle so the water runs down the inside wall of the vial rather than jetting onto the powder.
- Let it dissolve on its own. Swirl gently if it needs help. Do not shake.
- Label the vial with the date you reconstituted it before you put it away.
Shaking is the one step people get wrong. It is unnecessary and it damages the compound you just dissolved.
How much bac water do you need per vial size?
The arithmetic is the same every time: concentration equals milligrams divided by millilitres. More diluent gives a weaker solution and larger measured volumes, less gives a stronger one and smaller volumes.
| Vial | Bac water added | Concentration |
|---|---|---|
| 2 mg | 1 mL | 2 mg per ml |
| 5 mg | 1 mL | 5 mg per ml |
| 5 mg | 2 mL | 2.5 mg per ml |
| 10 mg | 1 mL | 10 mg per ml |
| 10 mg | 2 mL | 5 mg per ml |
| 10 mg | 3 mL | 3.33 mg per ml |
| 15 mg | 3 mL | 5 mg per ml |
| 20 mg | 2 mL | 10 mg per ml |
| 30 mg | 3 mL | 10 mg per ml |
| 50 mg | 5 mL | 10 mg per ml |
For any combination not in the table, the reconstitution calculator works it out.
How should you store it before and after puncture?
- Before puncture: room temperature, 20°C to 25°C, out of direct light. No refrigeration.
- After puncture: same conditions, and write the date on the label.
- Discard good until the printed expiration date when kept refrigerated, or at the printed expiry, whichever comes first.
- Whatever you reconstitute may need refrigerating even though the diluent does not.
How long does bac water last?
Unopened, until the expiry date printed on the vial. Once punctured, the expiration date. Those are two separate clocks and the one that matters is whichever runs out first.
How do you tell if a vial has gone bad?
Hold it up to a light. It should be completely clear and completely empty of particles. Cloudiness, floating matter, any tint, a cracked stopper or a broken seal all mean discard. So does an unlabelled vial you cannot date.
What is included?
- One sealed 30 mL multiple-dose vial of bacteriostatic water for injection, USP, per unit ordered.
- Flip-off cap and aluminum seal intact, lot number and expiry printed on the vial.
- Rigid protective packaging with no product name on the outside.
Should you buy the 10mL or the 30mL?
| 10 mL | 30 mL | |
|---|---|---|
| Best for | One or two reconstitutions | Regular or repeated use |
| Cost per mL | Higher | Lower |
| Risk of waste | Low | Only if unused before the expiration date |
The 30mL is better value per mL, but only if you will actually use it inside the window. Buying two 10mL vials and opening them a month apart wastes less than throwing away half a 30mL.
How is it packaged and shipped?
Orders before 3pm go out the same business day. Glass travels in rigid protective packaging, and the outside of the box carries an address and nothing else. Shipping is a flat $7.95. Full terms on the shipping and returns page.
What is frequently bought with it?
- Insulin syringes, for drawing the reconstituted solution.
- Mixing syringes, for moving diluent into the vial.
- Alcohol prep pads, for the stopper before every puncture.
- Empty sterile vials, if you are splitting a preparation.
- A sharps container.
Frequently Asked Questions
- How many times can you use a 30mL vial of bac water?
- A 30mL vial can be punctured repeatedly after the first draw, because the 0.9% benzyl alcohol suppresses microbial growth between uses. How many reconstitutions that covers depends on how much diluent each one takes.
- How should you store bac water?
- Bac water is stored refrigerated and is good until the expiration date printed on the vial, typically several years from manufacture. Whatever you reconstitute with it has its own, usually shorter, storage requirement.
- Does bacteriostatic water need to be refrigerated?
- Bacteriostatic water does not need refrigeration. Store it at 20°C to 25°C, which is ordinary room temperature, with excursions permitted between 15°C and 30°C. What you reconstitute with it may have its own storage requirement.
- How can you tell if bacteriostatic water has gone bad?
- Hold the vial to the light and look for cloudiness, floating particles, or any change in color from completely clear. Check the stopper for cracks and the seal for damage. If the vial is past the expiration date from first puncture or past its printed expiry, discard it whichever way it looks.
- Why does bacteriostatic water contain benzyl alcohol?
- Benzyl alcohol at 0.9% is the bacteriostatic agent, and it is what makes the vial multiple-dose. It suppresses the growth of bacteria introduced when the stopper is punctured, which is why a preserved vial can be drawn from repeatedly and an unpreserved one cannot.
- Is bacteriostatic water the same as sterile water?
- No. Bacteriostatic water contains 0.9% benzyl alcohol and can be used. Sterile water contains no preservative and is single-use, discarded immediately after opening.
- What size bac water vial should you buy?
- Buy the 30mL vial if you reconstitute regularly or work through several vials, and the 10mL if you are doing one or two. The 30mL is better value per mL, but only if you can use it before the expiration date.
- Can bacteriostatic water be used for anything other than reconstitution?
- Bacteriostatic water is a diluent, so its role is reconstituting a compound supplied as a powder. Bacteriostatic water is supplied for laboratory research use only and has no activity of its own.
- How is this vial shipped?
- Orders placed before 3pm ship the same business day in rigid protective packaging. Shipping is a flat 7.95, and nothing on the outside of the box names the contents.
Important notices
Bacteriostatic water for injection, USP sold on this site is supplied strictly for laboratory research use only. It is not a drug, not a dietary supplement, and not intended for human or veterinary use, diagnosis, treatment, or the prevention of any condition. It may not be administered to humans or animals. By ordering you confirm you are a qualified buyer purchasing for in vitro research conducted in a controlled laboratory environment.