A multiple-dose container is one the manufacturer designed for repeated withdrawals, and it carries a preservative for that reason. A single-dose container is opened once and the rest is discarded. The word on the label decides which you have; the volume and the look of the vial do not.
What the label means by multiple-dose
The prescribing information for Bacteriostatic Water for Injection, USP describes the product as supplied in a multiple-dose container from which repeated withdrawals may be made. That is the whole definition: the container is designed to be entered more than once. The 30 mL Hospira vial carries the words Multiple-dose Vial on its label, and AUBACWATER's own-label 3, 10, 20 and 30 mL vials are multiple-dose vials too.
Nothing about the glass, the stopper or the flip-off cap tells you this on its own. Single-dose and multiple-dose vials can look alike. The statement on the label is what distinguishes them.
Why a multiple-dose vial carries a preservative
Once a vial has been entered, its contents are no longer in a sealed, sterile container. A product meant for repeated withdrawals therefore carries a bacteriostatic preservative to inhibit the growth of bacteria that might be introduced. In bacteriostatic water that preservative is benzyl alcohol at 0.9% (9 mg/mL), or 1.1% in one glass presentation, and the same 0.9% benzyl alcohol appears in bacteriostatic 0.9% sodium chloride.
Bacteriostatic means growth-inhibiting. It does not mean sterilising, and the preservative does not restore sterility to a container that has been contaminated or handled badly. It also does not extend the expiry date on the label.
Single-dose containers are the opposite case
Sterile Water for Injection, USP contains no bacteriostat, antimicrobial agent or added buffer, and for that reason its label says it is supplied only in single-dose containers. The same label instructs: do not reuse single-dose containers; discard the unused portion. Without a preservative there is no basis for keeping an opened container.
So the two products answer the same question in opposite ways. Bacteriostatic water: multiple-dose, preservative present. Sterile water for injection: single-dose, no preservative, discard the remainder. Buying one when you needed the other is the most common mix-up between clear vials, and the label term is the quickest way to avoid it.
| Product | Container statement | Preservative | What the label says about the remainder |
|---|---|---|---|
| Bacteriostatic water | Multiple-dose; repeated withdrawals may be made | 0.9% benzyl alcohol (1.1% in one presentation) | Not stated on the label; the container is designed for re-entry |
| Sterile water for injection | Single-dose containers only | None | Do not reuse; discard unused portion |
| Bacteriostatic 0.9% sodium chloride | Multiple-dose; repeated withdrawals may be made | 0.9% benzyl alcohol | Not stated on the label; the container is designed for re-entry |
What to check on a multiple-dose vial when it arrives
Because the container will be in use for a period rather than opened once, the identifying details on it matter more, not less. Record them while the label is clean and legible.
- The words multiple-dose on the label, matching the product you ordered.
- The preservative and its percentage, printed on the label.
- The lot or batch number and the expiry date; write them into your stock record on arrival.
- The storage statement, 20 to 25 °C on the three labels above, and any in-use period the label sets; this article does not set one.
- That the flip-off cap is intact and the stopper undisturbed before the vial goes into storage.
What this article does not cover
It explains a label term. It does not describe how any product is prepared, withdrawn, mixed or used, and it is not medical or clinical advice. AUBACWATER's own-label vials are supplied for laboratory use and are not for injection, infusion or administration; the Hospira presentation is a manufacturer-labelled diluent to be used only as its label directs.
Sources
- Bacteriostatic Water for Injection, USP, multiple-dose vial: prescribing information published by Hospira, Inc. (DailyMed, US National Library of Medicine; label revised August 2019)
- Sterile Water for Injection, USP, single-dose: prescribing information (DailyMed, US National Library of Medicine)
- Bacteriostatic 0.9% Sodium Chloride Injection, USP, multiple-dose vial: prescribing information published by Hospira, Inc. (DailyMed, US National Library of Medicine)
These guides support product comparison and stock organisation. Follow the exact product label and intended-use information for the presentation you choose.
