Preservative efficacy testing
Start with the big picture
PET challenges a product with specified microorganisms and measures their recovery over time. The compendial panel includes bacteria and fungi, with additional in-house isolates considered when product risk warrants. Testing involves preparing a standard inoculum, incubating under specified conditions, sampling at defined intervals, and enumerating organisms on suitable media. Because residual preservative can continue killing organisms during plating, neutralization or dilution must be validated to prevent carry-over effects. Acceptance criteria depend on product category; the source gives a Category 1 parenteral criterion as an example, not a universal rule. PET is performed on the final container–closure system, repeated after formulation or manufacturing changes, and incorporated into stability assessment through release and end-of-shelf-life.
What you'll learn
- Explain the purpose of PET and the products to which it applies.
- Identify the compendial challenge panel and when additional isolates may be considered.
- Outline inoculation, incubation, sampling, enumeration, and preservative neutralization.
- Describe how product category and lifecycle changes relate to PET acceptance and testing.
- Recognize key documentation elements for PET records.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
