Overview

Bacteriostatic Water (often labeled Bacteriostatic Water for Injection, USP) is a sterile, nonpyrogenic water preparation containing benzyl alcohol as a bacteriostatic preservative.
It is designed for multi-dose use where repeated withdrawals are made under aseptic conditions.

In laboratory workflows, bacteriostatic water is commonly used as a diluent for reconstitution or preparation of test solutions when a preserved, multi-dose aqueous vehicle is required by protocol.

Composition & specifications (per labeling)

• Base: Water for Injection
• Preservative: benzyl alcohol (commonly listed as 0.9% = 9 mg/mL; some labeled products may list 1.1% = 11 mg/mL)
• Container type: multi-dose container intended for repeated withdrawals
• pH: approximately 5.7 (range 4.5–7.0) in common labeled products

Common research/lab uses

• Reconstitution vehicle for compounds requiring an aqueous preserved diluent (protocol-dependent)
• Method development where multi-dose withdrawal stability is needed (aseptic technique required)
• Control/vehicle in studies comparing preserved vs non-preserved aqueous diluents

Handling & storage (general guidance)

• Use aseptic technique for each withdrawal to maintain container integrity.
• Keep tightly closed when not in use; store according to manufacturer labeling and your lab SOPs.
• Do not substitute for sterile, preservative-free water when your protocol requires single-dose or preservative-free conditions.

RUO disclaimer

For Research Use Only when supplied as a research reagent by Trusted Peptides. If using a USP-labeled pharmaceutical product, follow the manufacturer’s labeling and institutional policies.

Selected references

• Pfizer labeling PDF: Bacteriostatic Water for Injection, USP
• DailyMed: Bacteriostatic Water for Injection, USP