In this article from Issue 12 of the Analytix Reporter, produced by Merck, learn more about the manufacturing and certification of the company's cannabinoid CRMs, for use as calibration solutions, for system suitability testing, and qualitative screening.
The interest in cannabinoid quantitation or potency testing of marijuana and hemp continues to grow with the expanding commercialization of cannabis dietary supplements and recreational products. While most of the U.S. states have legalized marijuana for medical use and several for recreational use, it still remains federally illegal and is classified as a schedule 1 substance. The growing of hemp crops in the U.S. was federally legalized by the U.S. Agricultural Improvement Act of 2018, also known as the 2018 Farm Bill. The U.S. Department of Agriculture (USDA) final rule for hemp production published on January 19, 2021 requires the total Tetrahydrocannabinol (THC) content of plant material on a dried weight basis to be less than 0.3% for it to be legally defined as hemp.
The accuracy of a testing laboratory’s calibration standards is a critical factor that directly impacts the accuracy of the test results. The labs must manufacture or purchase a suitable raw material or solution-based reference material for use as a calibrator. Availability of cannabinoid Certified Reference Materials (CRMs) allows testing laboratories to make cost-effective in-house calibrators, traceable to the CRMs, thereby contributing to a higher level of test accuracy and reproducibility.
The ISO defines a reference material (RM) as a material that is homogenous, stable, and fit for its intended measurement use. A CRM must meet additional requirements to those for RMs. CRM characterization methods must be metrologically valid and traceable to the measurement unit of the certified property value. The ISO guides give some flexibility to the CRM manufacturers as to how they meet these requirements.
As a result, the certification process can vary widely among the manufacturers, from assigning a potency from a simple chromatographic purity to a comprehensive MBPF approach. Cannabis testing laboratories must be mindful of this and review the CRM’s certificate of analysis (CoA) to ensure it is fit for their intended use.
Merck has developed CRMs of individual cannabinoids as well as mixes. These can be used for potency profiling of both hemp and cannabis. Specifically, the Hemp Compliance Mix was formulated to simplify standards preparation for analysis of THC content in hemp. Using rigorous process controls and formulation studies, stable cannabinoid mixtures have been formulated. Optimized raw material and packaging processes protect cannabinoids from oxidation, thus producing CRMs with long term stabilities. With the variability in testing methods and accreditation across laboratories, the use of accurate and traceable and properly certified CRMs is critical.
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*The life science business of Merck operates as MilliporeSigma in the U.S. and Canada.