Blog articles

Multiple use of sterile filters?

Written by Dr. Janet Thode on . Posted in Filter validation


Some time ago, I received a very interesting request that I’d like to use as an opportunity for writing this blog article.


The question

According to the draft of the revised Annex 1 "Manufacture of Sterile Medicinal Products" of the EU GMP guidelines, sterile filters should be discarded after having been used. Multiple use is excluded, with the exception that a use for more than one working day has been validated. This phrasing is not quite unambiguous. So how should we interpret the following requirement "Liquid sterilizing filters should be discarded after the processing of a single lot. The same filter should not be used for more than one working day unless such use has been validated." (8.89)?

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Influence of polysorbate 20 on the filter integrity test of a PVDF sterile filter

Written by Gastautor on . Posted in Filter validation

As part of the release testing of parenteral pharmaceuticals, sterility of the pharmaceuticals must be ensured after filling. Since a direct check of every filled vial or every syringe cannot be performed, the sterile filters are checked for their integrity, more precisely for their pore diameter, instead. According to the specifications of the WHO, a pore diameter of maximum 0.2 µm is allowed for sterile filtration [1]; accordingly, filtration with a sterile filter possessing a pore diameter of 0.2 µm or less results in a sterile filtrate.

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Review of the book “Analytische Qualitätskontrolle und pharmazeutische Mikrobiologie” (Analytical Quality Control and Pharmaceutical Microbiology)

Written by Dr. Janet Thode on . Posted in Think out of the box

As with some of the previous reviews, this book has also been part of my vacation reading and, in addition to the already hot temperatures, made me sweat a lot ;-)

Therefore, this blog article contains the review of the book "Analytical Quality Control and Pharmaceutical Microbiology", which Concept Heidelberg published in 2015 as part of the Pharma Technology Journal series by Editio Cantor Verlag in the first edition (ISBN: 978-3-87193-424-7).

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Limit tests - (when) do they play a role?

Written by Dr. Janet Thode on . Posted in Method validation

Purity determinations are applied as part of the quality control of pharmaceuticals, their active pharmaceutical ingredients (and, if applicable, their excipients in case they are not yet obtained in compendial quality). This includes quantitative determinations, resulting in a definite statement of the quantity or concentration, as well as qualitative / semi-quantitative determinations with results allowing only conclusions to be drawn as to whether the impurity is present or not or whether it is below a certain limit value. Such determinations are also known as "limit tests". Some people will think back to a laboratory practical training in drug analysis during their studies with more or less enthusiasm when they hear the word "limit test"...

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Calculation template for the evaluation of precision during method validations

Written by Dr. Janet Thode on . Posted in Method validation

To make work easier, I’d like to continue with our already started template series and today I’d like to post a template that can be used during method validations to evaluate the validation parameter precision (including repeatability, instrumental precision, and two versions for intermediate precision).

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Using the relative response for method validations and routine measurements

Written by Dr. Janet Thode on . Posted in Method validation

A wide variety of analysis methods are used in the pharmaceutical quality control laboratory. In addition to methods to proof the identity of the active pharmaceutical ingredient and qualitative tests, quantitative determinations are also included. A (calibration) standard of different concentrations is run in parallel within each analysis and the intensity of the measurement signal (detector response) is then plotted against the concentration.

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