For laboratory research use only.
Bacteriostatic water is sterile water that includes a bacteriostatic preservative. In research catalogs it is listed as a vehicle material, not as an active peptide or other analyte.
Composition
Official labeling for Bacteriostatic Water for Injection, USP describes a sterile, nonpyrogenic preparation of water for injection containing benzyl alcohol as a bacteriostatic preservative. Common labeled strengths are 0.9% (9 mg/mL) or 1.1% (11 mg/mL) benzyl alcohol (DailyMed labeling). Because more than one preservative strength appears in official labeling examples, the vial label for the lot in hand is the authority for what was received.
Compared with sterile water
Sterile Water for Injection is prepared from Water for Injection that is sterilized and packaged without an antimicrobial agent or other added substance, according to the USP monograph framing (USP Sterile Water for Injection). Bacteriostatic water and preservative-free sterile water are therefore related aqueous vehicles with different preservative status. A method that names one should not treat the other as an unspoken equivalent.
Why vehicle identity matters in research records
Preservatives can change some cell-assay backgrounds or interact with analytes. Recording the named vehicle from the method and the labeled product that was used keeps datasets interpretable when labs compare results across lots or sites. This article covers composition and identity only.
Sources
- DailyMed: Bacteriostatic Water for Injection labeling (benzyl alcohol 0.9–1.1%)
- Sterile Water for Injection (USP monograph: no antimicrobial agent)