Sterile Water for Injection
Sterile water for injection is highly purified, sterile water without any preservative. It is suitable for single-use reconstitution only; once the vial is opened, it should not be used for additional doses due to lack of bacterial protection.
Overview
Sterile water for injection (SWFI) meets strict pharmaceutical standards for particulate matter and endotoxin levels but contains no antimicrobial preservative. Without benzyl alcohol or another bacteriostatic agent, any microorganisms introduced during needle puncture can multiply within the vial. For this reason, SWFI is intended for single-use: the entire vial contents are used at once and any remainder discarded. In practice, for research protocols requiring multiple doses from the same vial over days or weeks, bacteriostatic water is strongly preferred. SWFI may be appropriate in situations where benzyl alcohol is contraindicated (e.g., certain neonatal applications) or for a single-dose preparation to be used immediately.
Related Terms
Frequently asked questions
When should sterile water be used instead of BAC water?+
Sterile water is appropriate when the entire reconstituted vial will be used in a single session, or when the protocol specifies avoiding benzyl alcohol.
Is sterile water the same as distilled water?+
No. Sterile water for injection meets strict pharmaceutical standards for sterility, pyrogen levels, and particulate matter. Distilled water does not meet these standards and is not suitable for injection.
Can I sterilize regular water for use as a diluent?+
No. Sterilizing water at home cannot reliably remove pyrogens (bacterial endotoxins) or meet pharmaceutical sterility standards. Only commercially prepared sterile water for injection should be used.