Method Suitability

We perform two types of suitability testing. One tests for the suitability of the counting methods in the presence of a product, and is governed by USP <61>. The other tests for the suitability of the test methods in the presence of a product and is governed by USP <62>.

What is suitability testing, and why is it significant?

Suitability testing is an integral part of any microbiological test system. It allows us to determine the appropriate diluent/dilution factors/enrichment media required to neutralize any inherent antimicrobial properties of drug products and ingredients (tested according to USP chapters <51>, <61> and <62>) when sample preparations are challenged with specific, viable test microorganisms. We perform two types of suitability testing. One tests for the suitability of the counting methods in the presence of a product, and is governed by USP <61>. The other tests for the suitability of the test methods in the presence of a product and is governed by USP <62>. In either case, select test organisms are spiked into the product and cultured. The sample passes if a certain percentage of the organisms are recovered, proving the culture method suitable for the product.

When and how often is this test administered?

Suitability testing is the first test performed on new samples. As long as the formula of a finished product is not changed, this test need only be administered once.

We note that some of our clients request that we run several tests concurrently, including suitability testing, but we recommend that suitability testing be performed prior to any other tests. Should suitability testing fail for your product, then the results of any concurrent tests would be invalidated and unusable.

What methods do you follow for suitability testing?

We follow USP <51>, <61> and <62> for all suitability testing. Our FDA-regulated laboratory meets strict CGMP requirements, including rigorous documentation and quality assurance for all testing performed.

Do I need to get suitability testing for my sample?

We highly recommend suitability testing for all products, especially when products are being submitted to the FDA for approval. CGMP regulations, which are enforced by the FDA, require that methods are suitable for a given product. The FDA will require evidence that the tests given are valid for a given product with a recorded demonstration of validity.

In the absence of suitability testing, we would perform generic testing methods on your sample, but we would not be able to verify that the testing methods were valid for your sample. Consequently, there is a probability of obtaining false results. For example, if a sample contains antimicrobial properties, but those properties are not discovered during suitability testing and the sample is subjected to generic testing methods without accounting for or neutralizing antimicrobial properties, it is highly probable that any contamination in the sample will go undetected and result in a false negative.

Without suitability testing, the product will not withstand FDA scrutiny.

How should I submit my samples?

Samples must be shipped to us in sterile containers. Contaminated containers could cause false positive results as our testing methods will detect contamination that does not necessarily originate from the sample itself. It is not possible to distinguish if a sample fails its testing specifications due to contaminated sample containers or faulty manufacturing process. In either case, the manufacturer may need to discard the contaminated stock and investigate their processes, which can result in loss of time and money. Therefore, it is in your best interest to carefully package your samples in sterile containers to prevent loss of time and product.

Add Sample amount. All Suitability requires 150g. All Routine Testing requires 30-40g.

What types of products have you performed suitability testing on?

We can run suitability tests on many products. Examples of products we have run suitability tests on include pharmaceuticals, cosmetics, ointments, and toothpaste.

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