Efficacy of Anti-Microbial Preservation - Eurofins Scientific
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Efficacy of Anti-Microbial Preservation

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he purpose of the preservative effectiveness test (PET) is to evaluate microbiologically the efficacy of preservative(s) added in samples using multidose containers. The efficacy of the preservatives is assessed by direct inoculation and mixing of the test bacterial strains into the sample product and tracking the survival of the test bacterial strains over time.

Precaution must be taken to minimize the amount of preservatives used, and the PET provides the justification for the amount of preservatives.

Example of Drug Products with Preservatives Added (Multidose Containers)

  • Oral liquid preparations
  • Topical preparations (such as creams)

Test Method

  • JP General test; Preservative effectiveness test
  • USP <51> Antimicrobial effectiveness test
  • EP 5.1.3 Efficacy of antimicrobial preservation


  • Biosafety cabinet
  • Laminar flow hood
  • Spiral plater
  • Incubator (30°C − 35°C, 20°C − 25°C etc.)