Revalidate Water for Injection (WFI) Generation Systems Periodically

Do Revalidate Water for Injection (WFI) Generation Systems Periodically

Remember: Perform periodic revalidation of WFI systems to ensure continued microbial quality, equipment performance, and GMP compliance.

Why This Matters in GMP

Water for Injection (WFI) is a critical utility used in sterile product manufacturing, cleaning of product-contact parts, and as a diluent for injectable drugs. Over time, even well-maintained systems can experience changes in performance due to scale build-up, component wear, microbial ingress, or changes in feed water quality. Revalidation helps confirm that the system still consistently produces water meeting pharmacopeial and GMP specifications.

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For instance, if a multi-effect distillation unit has not been revalidated in two years, subtle degradation in heat exchanger efficiency or an undetected breach in a condenser seal could lead to elevated endotoxin or microbial levels. Without routine revalidation, such deviations could go unnoticed and compromise product sterility and patient safety.

Regulatory and Compliance Implications

21 CFR Part 211.63 mandates the use of appropriately designed, sized, and maintained equipment. EU GMP Annex 1 requires requalification of water systems and emphasizes continuous verification of performance. WHO GMP recommends periodic review of critical utility systems to ensure consistent performance over time.

Regulators expect documented evidence of

system validation, including installation qualification (IQ), operational qualification (OQ), performance qualification (PQ), and ongoing periodic requalification. Gaps in revalidation can result in findings under utility control, validation program deficiencies, or water quality failures.

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Implementation Best Practices

Define revalidation frequency based on system complexity, historical performance, and product risk. Include microbial, chemical, and endotoxin testing at critical user points during PQ. Review alarm histories, maintenance logs, and calibration data as part of requalification planning.

Ensure QA approval of revalidation protocols and reports. Integrate trending data from routine sampling into risk-based assessments. Train utility and quality teams on identifying signs of performance drift and initiating early revalidation triggers.

Regulatory References

– 21 CFR Part 211.63 – Equipment suitability and maintenance
– EU GMP Annex 1 – Water system validation
– WHO TRS 970, Annex 3 – Pharmaceutical water system validation
– USP – Water for Pharmaceutical Purposes

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