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4.6 Antimicrobial effectiveness testing
Antimicrobial preservatives are ingredients added to dosage forms to protect them from microbiological growth and associated degradation. Where antimicrobial preservatives are added to a product, tests must be utilized that demonstrate the effectiveness of antimicrobial protection are performed on the product. Test methods used and tolerance limits should be as specified in an acceptable Pharmacopoeia (e.g., current USP <51>; Ph. Eur. 5.1.3), and should be performed on the final dosage form with suitable limits included.
The concentration of the preservatives shown to be effective in the final dosage form should be below a level that may be toxic to human beings, and should be at the lowest concentration necessary to preserve the product.
Original Message:
Sent: 08-May-2024 15:56
From: Tim White
Subject: Canada NHP - test method for antimicrobial properties
Hello Forum,
Would anyone be able to recommend a test method to show that a material has antimicrobial properties? Canadian Natural Health Products (NHP) GMP guidance includes an exemption to microbial contaminant testing if the manufacturer is able to demonstrate this. I contacted our Lab and they did not have an answer. I would think it must be a test where contaminants are added and then monitored for viability. If it's just a test for the presence of contaminants it wouldn't be conclusive whether the material was antimicrobial or the samples were just not contaminated.
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Tim White
RA Manager
Frisco TX
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