Medidental

Bacteriostatic water vs. sterile water

Both are the same water to begin with. USP defines bacteriostatic water as containing one or more antimicrobial agents, and sterile water as containing none — nor any other added substance. Neither definition mentions a container.

Bacteriostatic water vs. sterile water
Labeler Product Name Preservative Container Type Volume NDC
Hospira, Inc. Bacteriostatic Water for Injection, USP 0.9% or 1.1% benzyl alcohol Multiple-dose container — —
HF Acquisition Co LLC (HealthFirst) BACTERIOSTATIC WATER INJECTION, SOLUTION 1.1% benzyl alcohol Multiple-dose container 30 mL 51662-1473-1
Fujian Genohope Biotech Ltd. BACTERIOSTATIC WATER INJECTION, SOLUTION — Multiple-dose container 30 mL —
Medefil, Inc. STERILE WATER (Sterile Water for Injection) None (No antimicrobial or added buffer) Single-dose container — —

What are the official definitions?

Both products originate from a single base article. The USP-NF defines this article as Water for Injection. The USP-NF Water for Injection monograph (M88820_04_01, 2018 edition preview) states the base is purified water. It contains "no added substance."

The definitions diverge asymmetrically in their respective USP-NF monographs. Both monographs were compared string-by-string at the publisher's official host on 2026-08-07. The USP-NF Bacteriostatic Water for Injection monograph (M88830_03_01, 2017 edition preview) defines its product as "prepared from Water for Injection that is sterilized and suitably packaged, containing one or more suitable antimicrobial agents." In contrast, the USP-NF Sterile Water for Injection monograph (M88870_05_01, 2020 edition preview) defines its product as "prepared from Water for Injection that is sterilized and suitably packaged," but specifies that "It contains no antimicrobial agent or other added substance." This distinction is not merely about a preservative. The sterile definition excludes a broader class of additives, including buffers. The bacteriostatic definition requires an antimicrobial agent.

What do the labels say?

The contrast between these two products is mirrored on manufacturer labels. The labels use identical opening phrases. Hospira, Inc.'s label (document LAB-0977-2.0, revised 08/2019) describes its Bacteriostatic Water for Injection, USP as "a sterile, nonpyrogenic preparation of water for injection containing 0.9% (9 mg/mL) or 1.1% (11 mg/mL) of benzyl alcohol added as a bacteriostatic preservative." It notes the product is "supplied in a multiple-dose container." Medefil, Inc.'s label describes its Sterile Water for Injection, USP as "a sterile, nonpyrogenic preparation of water for injection which contains no bacteriostat, antimicrobial agent or added buffer and is supplied only in single-dose containers."

USP monographs stop at the phrase "suitably packaged." They do not define container types. The container designation comes from each label instead. Hospira's names a multiple-dose container and Medefil's names a single-dose container. On volume the labels converge: Hospira, HF Acquisition and Fujian Genohope each publish a 30 mL multiple-dose presentation, three of the four bacteriostatic labels read here.

What the labels print about neonates

Henry Schein, Inc.'s label carries the restriction as a boxed warning, which reads: "Multiple-dose Vial WARNING: NOT FOR USE IN NEONATES." Hospira's label also states a neonatal warning. "Where water is required for preparing or diluting medications for use in neonates, only preservative-free Sterile Water for Injection should be used."

For official FDA definitions on container designations, refer to single-dose vs. multi-dose vials. That page outlines recommended standards for multiple-dose and single-dose packaging. Detailed distinctions on irrigation water are available at sterile water for injection vs. irrigation. Our methodology is outlined in how we verify specifications.

We do not link a retail listing here. Every row above is a prescription drug product identified by an NDC, and a listing would have to carry that NDC to match one.

Sources

Specifications last verified: