Filter Validation Revalidation Impact Assessment

Document type	Risk Assessment
Topic area	Drug Product
Level	Advanced
Updated	September 2026

This is a ready-to-use risk assessment for evaluating, at every process, formulation, or filter change, whether the existing sterilizing filter validation package still applies. Attach it to the relevant change control record. 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.

Document control header

Field	Entry
Document title	Filter Revalidation Impact Assessment for `<<FILL: change description>>`
Document number	`<<FILL: e.g. RA-FLT-021>>`
Version	`<<FILL>>`
Effective date	`<<FILL>>`
Linked change control number	`<<FILL>>`
Filter / membrane under assessment	`<<FILL>>`
Document owner	`<<FILL: e.g. Filter Validation Lead>>`

1. Purpose

This assessment determines whether a proposed process, formulation, or filter-manufacturer change invalidates any part of the existing sterilizing filter validation package, either the bacterial retention claim, the integrity test correlation, the bracketing rationale, or the extractables and leachables conclusion, and defines the action required before the change is implemented.

2. Scope

Dimension	Decision
Change under assessment	`<<FILL>>`
Existing filter validation package referenced	`<<FILL: document number>>`
Change category	`<<FILL: process parameter / formulation / filter sterilization method / filter manufacturer or membrane>>`
Out of scope	`<<FILL: e.g. downstream container closure integrity, covered separately>>`

3. Responsibilities

Role	Responsibility
Filter validation lead	Facilitates the assessment, owns the conclusion and any follow-up study scope
Change control owner	Ensures this assessment is triggered and closed before the change is implemented
Formulation / process development	Confirms whether the change moves the product outside the bracketed or previously bacteriostasis-screened range
Quality Assurance	Approves the conclusion and any decision that no further filter validation work is required

4. Change classification

Classify the change against the categories below. More than one row applicable increases the scope of follow-up work required.

Change type	Applicable?	Retention claim affected?	Integrity test correlation affected?
Filtration time, pressure, volume, or temperature moves outside the validated range	`<<FILL: Yes/No>>`	`<<FILL>>`	`<<FILL>>`
Formulation concentration, excipient, or pH change outside the bracketed range	`<<FILL: Yes/No>>`	`<<FILL>>`	`<<FILL>>`
Filter sterilization method or cycle parameters change	`<<FILL: Yes/No>>`	`<<FILL>>`	`<<FILL>>`
Filter manufacturer changes membrane raw material, manufacturing site, or design	`<<FILL: Yes/No>>`	`<<FILL>>`	`<<FILL>>`
Membrane lot change within the manufacturer’s existing qualified process only	`<<FILL: Yes/No>>`	`<<FILL>>`	`<<FILL>>`

5. Impact evaluation

Question	Answer
Does the change move any process parameter outside the range the original bacterial retention study challenged?	`<<FILL>>`
Does the change move the formulation outside the bacteriostasis screen or bracketing rationale already on file?	`<<FILL>>`
Does the change affect how the filter is prepared or sterilized before use, potentially invalidating the integrity test correlation?	`<<FILL>>`
Has the filter manufacturer notified a change under the quality agreement that requires a sponsor-level review?	`<<FILL>>`
Does the manufacturer’s own bridging data cover this change, or is sponsor-level testing required?	`<<FILL>>`

6. Conclusion and required action

Field	Entry
Existing validation package still applies without further work	`<<FILL: Yes/No>>`
If No, required action	`<<FILL: new or extended bacterial retention study / bracketing re-evaluation / integrity test re-correlation / bridge to manufacturer data>>`
Owner and target date for the required action	`<<FILL>>`
Can the change proceed before the action is complete?	`<<FILL: Yes/No, with justification>>`

7. 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. Internal quality agreement with the filter manufacturer, change notification clause.

Confirm the current version of each reference before issue.

8. Revision history

Version	Date	Author	Summary of change
`<<FILL: 1.0>>`	`<<FILL>>`	`<<FILL>>`	Initial issue.

9. Approvals

Role	Name	Signature	Date
Author (Filter Validation Lead)	`<<FILL>>`
Reviewer (Process Development)	`<<FILL>>`
Approver (QA)	`<<FILL>>`

Filled specimen

Extract for an example change control proposing to increase a biologic drug product’s maximum filtration time from 4 to 8 hours to accommodate a larger commercial batch size. Company and product are illustrative.

Change type	Applicable?	Retention claim affected?	Integrity test correlation affected?
Filtration time, pressure, volume, or temperature moves outside the validated range	Yes, filtration time doubling from the validated 4-hour worst case	Yes	No
Formulation concentration, excipient, or pH change outside the bracketed range	No	Not applicable	Not applicable
Filter sterilization method or cycle parameters change	No	Not applicable	Not applicable
Filter manufacturer changes membrane raw material, manufacturing site, or design	No	Not applicable	Not applicable

Impact evaluation: the original bacterial retention study challenged a 4-hour maximum filtration time; an 8-hour run sits outside that validated worst case, and prolonged product-membrane contact time is itself a variable ASTM F838 studies are designed to bound. Conclusion: existing validation package does not cover the proposed 8-hour filtration time. Required action: request an extended bacterial retention study from the filter manufacturer at the new 8-hour worst-case parameter set, with the bacteriostasis screen re-confirmed at the longer contact time. Owner: Filter Validation Lead, target date set to precede the change control’s planned implementation date. The change cannot proceed to commercial batches until the extended study report is issued and approved; QA holds the change control open pending that report.

Common inspection findings this risk assessment prevents

A process parameter change implemented through change control with no linked review of the filter validation package it affects.
A filter manufacturer’s change notification received and filed with no sponsor-level impact assessment performed against it.
A revalidation impact assessment performed after the change is already running in commercial manufacture rather than before.
A conclusion of “no impact” reached with no documented comparison against the original validated worst-case parameters.

How to adapt this risk assessment

Link this assessment to the actual change control record in the header, not as a standalone document.
Classify the change honestly against every row in section 4; more than one applicable row is common and each one needs its own impact evaluation.
State plainly in section 6 whether the change can proceed before the required action closes, and get QA’s explicit position on record either way.
Confirm every reference in section 7 against the current published version before issue.