TL;DR
Fill volume deviation is usually a worn pump piston, a leaking check valve, or a fill needle tip blocked with product. Check and recalibrate the fill pump and valves first.
What you might see
- fill weight or volume outside specification on IPC sample
- systematic over-fill or under-fill on one fill station
- check valve leaking back between fills
- fill weight trend shifting after product change
Likely causes
Pump piston or barrel wear increasing the effective stroke volume
Check valve seat wear or particle contamination allowing back-flow
Fill needle tip partially blocked causing incomplete fill per cycle
Product viscosity change between batches altering the effective fill volume
Required tools
- Analytical balance for fill weight verification
- Fill pump disassembly kit
- Check valve inspection tools
- Replacement pump piston, barrel, and check valve parts
Safety first
- Follow GMP gowning and aseptic handling procedures throughout all work on the filling line. Improper gowning risks product contamination.
- Drug product residue on components can be biologically active. Wear appropriate PPE for the specific product class when disassembling wetted parts.
- Perform a cleaning validation hold before restarting production after any pump repair.
Procedure
- 1
Stop the line and perform an in-process check (IPC) sample of 10 vials from the affected fill station. Weigh each vial and calculate the mean and range.[1]
- 2
If the deviation is systematic (all vials over or under), adjust the pump stroke set-point incrementally and re-check after 5 vials.
- 3
Disassemble the fill pump and inspect the piston and barrel for wear, scratches, or scoring. Replace the piston and barrel as a pair if wear is visible.[1]
- 4
Inspect the check valves for seat wear or particulate lodged in the seat. Clean or replace the check valve balls and seats.
- 5
Check the fill needle tip for product buildup or deformation. Clean or replace the needle tip.
- 6
Verify the product viscosity against the specification. If a different product batch is in use, recheck the fill volume calibration.
- 7
After any repair, re-verify fill volume with a 10-vial IPC sample and accept only when the mean and range are within the batch record limits.
Sources
Bosch / Syntegon Syntegon FXS / FLS Vial / Syringe Filling Line general technical documentation, Bosch / Syntegon
Syntegon FXS / FLS filling line general pump maintenance and IPC procedures (general)
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Stop fixing the same fault twice.
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