PBL Logo - click here to return to homepage spacer



Antimicrobial Effectiveness Test (AET)

Nonsterile dosage forms of drugs typically have preservatives added to them in order to protect them from microbial contamination. Microbes can be introduced inadvertently during manufacturing, or during the continual use of a product.

The USP 51 antimicrobial effectiveness test, also known as the preservative efficacy test, is performed to determine if the chosen preservative is appropriate for a product formulation. It is also carried out as part of a stability study, to ascertain whether a preservative system is still effective up to the expiration date of a product. Testing is performed according to compendial requirements in both USP <51> and EP 5.1.3.

To evaluate the antimicrobial effectiveness of a product, the product is inoculated with a prescribed quantity of specified microorganisms. The effectiveness of the preservative is evaluated by comparing the initial level of microorganisms to the test sample at various time intervals over a period of 28 days at a specified temperature. Reduction of microorganisms is calculated logarithmically.

Available Antimicrobial Effectiveness Testing (AET) Services

  • AET Validation
  • USP (Category 1,2,3, and 4 Products)
  • EP/BP (Parenterals, Opthalmic, Topicals, and Oral Preparations)
  • Custom Studies

Antimicrobial Effectiveness Testing (AET) Standards

Antimicrobial Effectiveness Testing (AET) Related Testing

Read More About Antimicrobial Effectiveness Testing (AET)



Intertek Logo PBL is FDA registered and ISO 9001:2008 and ISO 13485:2003 certified by Intertek. AAALAC Logo Our animal science operations are accredited by AAALAC.

Request a quote Send an email