Water for Injection (WFI)

Water of high purity

As termed by the USP, WFI is considered to be a component or "ingredient materials" intended to be used in the production of drug products. According to the FDA, water for injection can only be made by distillation or reverse osmosis. Usually, it's produced using a continuously circulating system at a high temperature maintained throughout the system. Best practice is to dispose of WFI or divert to a non-WFI system 24 hours after being produced.