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Microbial Contamination Control: Part 1

As our industry evolves, we find ourselves more and more reliant upon the principals of Pharmaceutical Quality Standards, based upon 21 CFR Parts 210 and 211.


It is only a matter of time before cannabis becomes federally legal!


Our industry is continuing to recruit Subject Matter Experts (SMEs) in the pharmaceutical and biotechnology industries. Why? Because it is only a matter of time before cannabis becomes federally legal. When this occurs, Congress will enact legislation, and the Food and Drug Administration will become the compliance enforcement arm of the federal government, much as it did for the dietary supplements industry (21 CFR Part 111) and, later, the tobacco industry (21 CFR Part 1140).

One of the myriad aspects of current pharmaceutical current Good Manufacturing Practices (cGMPs) is microbial contamination control. In this blog, I wish to address one important aspect of this control: disinfectant efficacy testing (DET).

Pharmaceutical and biotechnology industries rely on the United States Pharmacopeia (USP) chapter <1072>, “Disinfectant and Antiseptics”, among other industry guidances. USP <1072> prescribes an approach for demonstrating adequate reduction of a microbial challenge, in the presence of a firm’s Materials of Construction (MOC), elicited by a pre-defined exposure to a disinfectant. Essentially, a 2” x 2” “coupon” of a MOC is first inoculated with a known concentration of a microorganism, followed by a timed exposure to a firm’s disinfectant(s). After exposure time, the surviving microorganisms are harvested and enumerated. The "before” and “after” concentrations are converted to log10 formats, and a log-reduction is calculated. The criteria in USP <1072> is that a 2-log reduction be achieved for vegetative microorganisms (such as non-spore-forming bacteria and yeast) and a 3-log reduction be achieved for spore-forming microorganisms (such as spore-forming bacteria [e.g., Bacillus spp] and molds).

The Parenteral Drug Association’s (PDA) Technical Report No. 70 provides excellent further guidance, in stating: “Selection of organisms should be based on the type of environmental isolates recovered from the facility”. In essence, this means that a firm should use its own microflora as its challenge panel (USP <1072> also supports this), instead of standard (“type culture”) microorganisms.

In a future blog, I will provide guidance on how to understand, trend, isolate and use a firm’s own microflora for this testing.

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