Yes they need to establish the equivalency of both offline and online filtration. I have few questions:
- Was there any planned deviation/temporary change control for this?. If yes what reason was given?
- Is this change is covered in the intervention sections of process validation? If no, how they got authorization to change the method.
- Was online method was part of BMR? or is it a regular practice of online filtration, however offline was only selected for this validaiton (as per your protocol)?
- was any risk assessment of offline method was performed?
see as PDA and PICS guidelines Time limits should be established for each phase of processing, and equivalency should be addressed to identify worst case scenario e.g.
- maximum period between start of bulk product compounding and sterilization (filtration)
- product exposure on processing line
- storage of sterilized containers/components
- total time for product filtration to prevent organisms from penetrating filter
- maximum time for upstream filters used for clarification or particle removal (can support microbial attachment)
The time limit for both the processes (offline/online) should be established and validated so if there is any change in key chain of process, for establishing it…a validation is required to document and establishment of limits.
for your further reading please refer below few informative links:
7.4 Intervention Monitoring