What is Water for Injection?
Water for Injection (WFI) is sterile water used for the manufacturing of pharmaceutical products which are administered parenterally, ophthalmically, or inhaled. WFI also is used for cell culture growth media, washing, and rinsing bioreactors in fast-growing biologic therapies.
Water for Injection is similar to purified water; it must meet the same quality requirements as this water purity classification but needs to undergo additional treatment to meet the strict endotoxin limits to be considered safe for injection.Â
Systems producing WFI also need to undergo a validation process to ensure it is producing water that meets the required specifications in order to be used safely.
Water for Injection Specifications
To be an acceptable source of WFI, the USP (US Pharmacopeia) and the European Pharmacopeia require that water produced using distillation or membranes must meet strict specifications for conductivity, bacteria, TOC (total organic carbon), and endotoxins. (See the chart below for WFI specifications).
Water for Injection Quality Requirements
| USP (US Pharmacopiea) | European Pharmacopoeia | Japanese Pharmacopoeia | |
|---|---|---|---|
| Conductivity |
< 1.3 μS/cm at 25°C* |
< 1.1 μS/cm at 20°C |
< 2.1 μS/cm at 25°C** |
| Bacteria |
<10 cfu / 100 ml (Guideline action limit) |
<10 cfu / 100 ml (Guideline action limit) |
<10 cfu / 100 ml (Guideline action limit) |
| TOC |
< 500 ppb |
< 0.5 mg/l*** |
< 0.5 mg/l |
| Endotoxin |
< 0.25 l.U. / ml |
< 0.25 l.U. / ml | < 0.25 l.U. / ml |
| * Offline conductivity measurements possible. If in-line conductivity exceeds values then refer to USP Â tables in section 645
**Offline conductivity limit after agitating ***or pass oxidizable substances test |
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