Validating Alternative Testing Systems

Originally Published March 2010

By June 25, all dietary supplement manufacturers will have to comply with the Food and Drug Administration's (FDA) current good manufacturing practices (CGMPs)-regardless of whether companies have 1000 employees or 10. When FDA comes to call, you must be ready to prove that your products meet every part of the CGMPs.

Section 111.310 is one of the CGMPs' more challenging provisions. The section specifies that every manufacturer must use "adequate laboratory facilities to perform whatever testing and examinations are necessary to determine whether, a) Components that you use meet specifications; b) In-process specifications are met as specified in the master manufacturing record; and c) Dietary supplements that you manufacture meet specifications."

In plain English, dietary supplement CGMPs require that manufacturers take steps to ensure that products are free of contamination by objectionable microorganisms. Manufacturers must be prepared to test raw materials and finished products for relevant microorganisms.

The devil is in the details. Traditional plate methods for testing require time and manpower. Simpler, streamlined alternative tests can help. But there is an often-overlooked detail that comes along with all alternative systems-that these systems must comply with the methodology described in the relevant chapters of the U.S. Pharmacopoeia, says BioLumix (Ann Arbor, MI), makers of the BioLumix System. Specifically, alternative systems must be validated against USP chapters 2021, 2022, and 2023. Guidelines to help determine the appropriate tests are found in chapter 2023. The actual quantitative and qualitative testing procedures are located in chapters 2021 and 2022. The official ruling on dietary supplement CGMPs (21 CFR Part 111) can be found in chapter 2750.

What Are Validation Tests?

System validation consists of a series of challenges or tests. Basically, a system is compared to other test methods to make sure it performs as designed.

The first step, installation qualification, includes major component identification and validation, validation of environmental conditions, electrical requirements, computer qualification, installation checklist, and calibration documentation. The second step, operation qualification, includes a unique standard operating procedure for all product assay combinations that need to be performed, training documents, software characteristics, certification, and verification of 21 CFR Part 111 compliance, as well as an operation checklist. The third part, performance qualification, is the heart of a validation package. It includes a side-by-side comparison of the system data to USP methodology.

The comparison is done individually for each assay. One example, using the BioLumix system: 159 samples were analyzed for total aerobic count at various specification levels. In the results, 113 samples were below specification by both methods, while 46 were above the specified level by both methods. There was 100% agreement between the two methods, which meant that the system passed for TAC measurement.

Specificity (also call inclusivity and exclusivity) involves testing each test vial to ensure that each bacteria strain can be determined. Detection limit is validated by comparing a system against another method, such as plate count. Repeatability is checked for standard deviation for each media determined using naturally contaminated samples and samples inoculated with various organisms. Robustness involves looking at how the system copes with small variations in test parameters. With the BioLumix system, the parameters were the effect of changes in the instrument incubator temperature, the effect of sample size, and the effect of medium volume in the vial. The robustness was tested in various media with several repetitions.

Ruggedness does not involve dropping a system on the floor-although most labs have seen worse stress on their equipment. Ruggedness measures how precise a system can be when challenged by a variety of test conditions. False-negative tests are performed by challenging the system to detect which samples that are inoculated or naturally contaminated generate a positive result in the reference method (plate count) compared with a negative in the system. False positive is a test in which a sample that is not inoculated with the target organism generates a positive result in the system, but not in the plate-count method.

The quality of a finished product with respect to microbial growth should never be undervalued, and maintaining appropriate microbiological product attributes is crucial. It is always better to spend a few extra dollars on additional testing rather than risk lawsuits or recalls.