Research Calculator
Bac Water Expiration Tracker
Bacteriostatic water vials with 0.9% benzyl alcohol preservative are typically considered usable for 28 days after first puncture, when stored at 2–8 °C. Enter the date you punctured the vial to see the calculated expiration.
28 days is the standard USP-aligned window for multi-dose preserved vials.
Result
Discard on or after
Saturday, June 20, 2026
28 days remaining.
Storage reminder
- • Refrigerate at 2–8 °C (36–46 °F)
- • Discard if cloudy, discolored, or has particulates
- • Use aseptic technique with every puncture
Informational only — not medical advice. Follow your institution's SOPs and the manufacturer's package insert.
The 28-day rule
United States Pharmacopeia (USP) general guidelines indicate multi-dose vials containing preservatives such as benzyl alcohol may be used for up to 28 days after the initial puncture, provided they are stored properly and free from visible contamination.
The 28-day window assumes:
- Refrigerated storage between 2 °C and 8 °C (36 °F – 46 °F)
- Aseptic technique when withdrawing from the vial
- No visible particulate matter, cloudiness, or color change
- An intact rubber septum that re-seals after each puncture
If any of these conditions are not met, discard the vial earlier. When in doubt, throw it out — a fresh 10 mL vial is inexpensive insurance.
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