SOP on integrity testing of cartridge filter.


To lay down a procedure for integrity testing of cartridge filter.


This SOP is applicable for integrity testing of cartridge filter in formulation plant.


Production officer / Executive shall be responsible for follow the procedure mentined in this SOP.


Production Head and QA Head shall be accountable for compliance of SOP.


SOP : Standard Operating Procedure.

IPA : Isopropyl alcohol


Pre Start up

Close the air vent of the filter housing.

Check the tightness of the clamp. It should not be loose at the connections.

Ensure that compressed air is available at a pressure of 4 to 6 kg/cm².

Start up

Wet the cartridge filter with Water for Injection (WFI) or Iso propyl alcohol (use Water for injection for hydrophilic filter and 70% Iso Propyl Alcohol (IPA) for hydrophobic filter) through the filter housing.

Open the air vent of filter housing so that air is removed form the vent and close the air vent when water for injection or Iso Propyl Alcohol droplet starts oozing out.

Connect the filter housing inlet to outlet of integrity testing instruments.

Connect the compressed air supply to the inlet of integrity testing instrument.

Open the valve of compressed air supply line and adjust the air pressure between 4-6 kg/cm² for the integrity testing instruments.

Connect the power supply of the instrument and switch ON the instrument.

Integrity testing instruments is itself start the self test programme.

During this test instruments check the correct functioning of internal communication, inlet pressure, pressure transducers, valves and regulators are checked. An internal leak test is also carried out.

After completion of self test, instrument display the main menu. Press the “Bubble Point” then after screen display the bubble point test.

Enter the PIN and Password then press Ok. Screen display the Bubble Point Test the test programme and press OK.

Check the test programme and enter the details as per given below:-

S.No Filter details Location Filter ID.No Catalogue/ Part No Minimum Bubble Point value
1.0 Hydrophobic Filter
1.1 Compressed air line Filter Vial washing Machine 1320 mbar
1.2 Compressed Air Line Filter Garment washing Area 1100 mbar
1.3 Compressed Air Line Filter Equipment Wash Area 1100 mbar
1.4 Compressed Air Line Filter Bung Processor Cum steam sterilizer  


1100 mbar
1.5 Compressed Air Line Filter Cooling Zone 1100 mbar
1.6 Vacuum Break Filter Bung Processor cum steam sterilizer sterile side (Cooling Zone) 1100 mbar
1.7 Compressed Air Line Filter Vial Filling machine 1320 mbar
1.8 Compressed Nitrogen Line Filter Vial Filling machine 1320 mbar
1.9 Compressed Air Line Filter Vial Filling Machine(Pneumatic Operation) 1320 mbar
1.10 Compressed Nitrogen Line Filter Vial Filling Machine (Process Operation) 1320 mbar
1.11 Vacuum Line Filter Vial Filling Machine 1320 mbar
1.12 carbon dioxide line filter Vial Filling Machine 1100 mbar
2.0 Hydrophilic Filter
2.1 Disinfectant solution, water for injection and IPA Cooling Zone 3450 mbar

Press the start to run the machine. In the bubble point test, pressure develop upto 700 mbar (10 PSI) then instrument check the pressure leak in the filter.

During the measurement phase of the test, pressure increases and simultaneously instruments measure the pressure decay.

When the develop pressure attain the specified minimium bubble point line then test result display “BP within limit” and if develop pressure not attain the specified bubble point line then test result display “ BP outside limit” so filter is defective.

If the filter fails in integrity on retesting, then reject the filter and replace it with new filter and check its integrity.

Shut Down

Disconnect the integrity testing apparatus from the filter housing.

Incase a sterilizing grade filter which is used for filtration of Nitrogen, Compressed Air  carbon dioxide in Vial Filling Room, fails in integrity test (post), inform the Production Manager and Quality Assurance. The Production Manager to initiate an investigation in consultation with Q.A for the failure. The decision for the release or disposition of batch to be taken by Q.A. department.

Record the integrity testing of cartridge filter details in Annexure No – 1


Every 15 days for air line cartridge filter/after dissembling of filter from the line.

Before and after sterilization of cartridge filter.

Before and after filtration of Water for Injection / Disinfectant solution/IPA


Integrity Testing of Cartridge Filter Record

Filter Location:                                                                                 Filter ID No.:

Filter Type:                                                                                       Pore Size:

Filter Part No.                                                                                  Filter Serial No.

Date Standard bubble Point value Measured bubble Point Value Result


Done By Checked By Remarks



Master copy –  Quality Assurance

Controlled copies- Quality Assurance, Production, Quality Control


Date Revision Number
Reason for Revision
00 New SOP


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