Liquid manufacturing- filtration process

Dear All,
What is the frequency of usage of filters used during filtration of bulk liquid solutions.?
How this frequency of usage let, 2 times or 5 times is selected?
How the integrity is checked?


Filter pads are used for filtration of bulk liquid solutions which are fitted in siutable size of filter presses.frequency of these is 12 cycles of usage.

Thank you,
from where i can get the reference for number of usage? any study required to prove it !!and what is the base for it?


The information that i have provided is as per our inhouse practices and sop.

I think that theoretically a non sterile liquid filter can be used as long as integrity tests pass and differential pressure across the filter does not exceed maximum allowable differential pressure stated by filter manufacturer.

But I think it is preferred to know the duration (no. of usages) after which the used filter in your non sterile facility typically deteriorates regarding integrity or differential pressure and define this duration in the SOP for changing the filter.

But in case of sterile liquid filter used for non terminally sterilized aseptically filled sterile products extensive validation studies for aseptic filtration process should be accomplished regarding maximum filter usage period and other filtration aspects. Generally it is preferred to use aseptic liquid filter not more than 1 working day and not more than 1 batch, according to EU Annex 1 Draft 2017 which is expected to be approved during this spring

Annex 1 Aseptic filtration.pdf (84.2 KB)

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Thanks you.

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According to our SOP we use filter cloth in Filterpress for 5 batches.

Sir, frequency of product filters is single time use,bz of cross product contamination. After each batch pre integrity should be performed same should be considered after filtration.

when it comes to batch count it differs from 8-12 batches but most important thing is these filter pads are to be changed if the Product is going to be changed. You cannot use a set of same filter pads to different batches.They must be changed, new ones are to be taken.
Not only 8-12 consecutive batches we can use but also a time period is to be maintained , example they should be used for consecutive batches within 1 month of duration. Even if they are used for less batches but the time period is completed then u have to change the filter pads.

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But what if there are set of dedicated filter bags for different products?

dedicated filter cloths should be used .

Dedicated bags can be used for 8-12 continuous batches (based on different products and companies) that too within 30 days of period.

maintaining dedicated filter bags is not an easy thing , if your particular manufacturing section manufactures 10+ products then u have to maintain separate log books for each of the product just to enter the details of each filter pad u use , you cannot maintain one log book for these many different dedicated filter bags. And more challenging part is maintaining them without getting mix-ups.
Maintaining dedicated filter bags is not less than a challenging part.

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Ok, What are the test to be conducted to define this limit besides integrity test?

Differential pressure across the filter

most simple may be the physical examination of filter cloth.