How to use this document
Copy the template below into your quality system. Replace every <<FILL: ...>> placeholder with your company, system, and process specifics, then route it through your own document control, review, and approval. The filled specimen shows one worked example; adapt the numbers and scope to your operation and verify each cited regulation or standard against the current source before you rely on it.
This is a generic, originally worded starting point. It contains no confidential, proprietary, or employer material, it is drafted with AI assistance and reviewed, it is not legal or compliance advice, and adopting it does not by itself create or prove compliance. See the Disclaimer and Terms.
This is a ready-to-use protocol for validating a sterilizing-grade filter for a biologic or oligonucleotide drug product: the bacterial retention study design, the bacteriostasis screen that decides whether the challenge runs on product or a surrogate fluid, and the physical integrity test correlation that stands in for retention testing in routine manufacture. Replace every <<FILL: ...>> placeholder with your own specifics and route it through your normal document control, review, and approval. A worked filled specimen follows. Verify each cited reference against the current source before you rely on it.
1. Purpose
This protocol defines the bacterial retention study, bacteriostasis screening, and physical integrity test correlation used to qualify <<FILL: filter model>> as sterilizing-grade for <<FILL: product>> at the stated worst-case process conditions, per ASTM F838 and PDA Technical Report No. 26.
2. Scope
3. Responsibilities
4. Prerequisites
5. Bacterial retention study design
6. Physical integrity test correlation
7. Test matrix
8. Acceptance criteria
9. Deviation handling
Log any deviation from the stated worst-case parameters, test fluid, or challenge level in real time. A deviation that changes what the study actually demonstrates, a lower challenge level, a less severe condition, invalidates the study for the intended claim regardless of the pass/fail result, and requires re-execution rather than a documented exception.
10. Summary and conclusion
State plainly whether the filter is qualified as sterilizing-grade for this product at these worst-case conditions, and whether the physical integrity test limit set here is the one released into the routine batch record.
11. References
ASTM F838, Standard Test Method for Determining Bacterial Retention of Membrane Filters Utilized for Liquid Filtration.
PDA Technical Report No. 26, Sterilizing Filtration of Liquids.
FDA guidance, “Sterile Drug Products Produced by Aseptic Processing: Current Good Manufacturing Practice” (2004).
EU GMP Annex 1 (2022), Manufacture of Sterile Medicinal Products.
Confirm the current version of each reference before issue.
12. Revision history
13. Approvals
Filled specimen
Extract for an example oligonucleotide drug substance final filtration step. Company, product, and numbers are illustrative.
The correlation study challenged 6 normally manufactured filters, 4 filters with a minor induced membrane stress, and 3 filters with a deliberate gross defect. All normally manufactured and minor-stress filters passed bacterial challenge with diffusive flow readings between 4 and 18 mL/min; all gross-defect filters failed bacterial challenge with readings above 60 mL/min, a clear separation supporting the 12 mL/min production limit with real margin.
Common inspection findings this protocol prevents
- A retention certificate covering generic conditions that do not match the actual worst-case process parameters.
- A direct product challenge run without first screening for bacteriostasis or bactericidal potential.
- An integrity test production limit with no visible correlation study behind it.
- A viability control omitted or not reported alongside the challenge result.
- A deviation from stated worst-case conditions treated as an acceptable exception rather than grounds for re-execution.
How to adapt this protocol
- Set your document number, product, and filter model in the header.
- Confirm the bacteriostasis screen in section 4 before scheduling the manufacturer study; this decision cannot be made after the challenge runs.
- Write your actual worst-case process parameters into section 5 explicitly; do not accept a generic manufacturer study as a substitute.
- Set the production integrity test limit in section 6 only from a real correlation study, with margin on the safe side of the retentive population.
- Confirm every reference in section 11 against the current published version before issue.
