When is an Antimicrobial Preservative Effectiveness test needed?

• Performed during product development
• Test the chosen preservative
• Stability program
• Product validation

What products need  USP <51> test?

• Multiple-dose topical and oral dosage forms
• Nasal aqueous products
• Otic products
• Antacids made with aqueous base

How much sample is needed?

Preferably 5 original containers containing at least 100 mL or 100 g.  This will be enough for validation purposes as well as product testing.

How it works?

A product is inoculated with a controlled quantity of specified microorganisms.
USP <51> requires 5 different microorganisms, for bacteria:

Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli; for yeast, Candida albicans, and for mold, Aspergillus niger.

If the criteria for the specific category is met, then the product requirements for AME pass.