Article

Thermal stability of cannabinoids in dried cannabis: a kinetic study

Authors:
  • National Research Council Canada, Halifax
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Abstract

This study was undertaken to quantitatively explore the effect of temperature on the degradation of cannabinoids in dried cannabis flower. A total of 14 cannabinoids were monitored using liquid chromatography and tandem mass spectrometry in temperature environments from − 20 to + 40 °C lasting up to 1 year. We find that a network of first-order degradation reactions is well-suited to model the observed changes for all cannabinoids. While most studies focus on high-temperature effects on the cannabinoids, this study provides high-precision quantitative assessment of room temperature kinetics with applications to shelf-life predictions and age estimates of cannabis products.

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... When the oil was stored at 20 and 25 • C, the half-lives were 49 and 20 days, respectively. Meija et al. [145] conducted stability testing on seven cannabinoid pairs (CBC, ∆9-THC, CBN, CBG, CBD, ∆9-THCV, and CBDV, as well as their acidic forms) in dried hemp material stored in the dark at temperatures ranging from −20 to 40 • C). The average monthly degradation of ∆9-THCA + ∆9-THC was 2% at 20 • C. It was observed that the storage of these compounds at 4 • C did not ensure long-term (more than 12 months) cannabinoid stability. ...
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Solutions of pure cannabinoids, nine samples of herbal and two of resin cannabis (one freshly prepared) were stored in varying conditions for up to 2 years. Exposure to light (not direct sunlight) was shown to be the greatest single factos in loss of cannabinoids especially in solutions, which should therefore be protected from light during analytical and phytochemical operations. Previous claims that solutions in ethanol were stable have not been substantiated. The effect of temperature, up to 20 degrees, was insignificant but air oxidation did lead to significant losses. These could be reduced if care was taken to minimize damage to the glands which act as "well filled, well closed containers". Loss of tetrahydrocannabinol after exposure to light does not lead to an increase in cannabinol, but air oxidation in the dark does. It is concluded that carefully prepared herbal or resin cannabis or extracts are reasonably stable for 1 to 2 years if stored in the dark at room temperature.
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A simple procedure based on a common silica gel column chromatography for the isolation of Delta9-tetrahydrocannabinolic acid A (Delta9-THCA-A) from hemp in a multi-milligram scale is presented. Further, the decarboxylation reaction of Delta9-THCA-A to the toxicologically active Delta9-tetrahydrocannabinol (Delta9-THC) at different analytical and under-smoking conditions is investigated. Maximal conversion in an optimised analytical equipment yields about 70% Delta9-THC. In the simulation of the smoking process, only about 30 % of the spiked substance could be recovered as Delta9-THC.
Government of Canada
Canada: Cannabis Act. In: Statutes of Canada. Government of Canada. 2018; https://laws-lois.justice.gc.ca/eng/acts/C-24.5/ fulltext.html.
ISO: Reference materials -guidance for characterization and assessment of homogeneity and stability
ISO: Reference materials -guidance for characterization and assessment of homogeneity and stability. In: Guide 35:2017. International Organization for Standardization. 2017; https:// www.iso.org/standard/60281.html.
Chemistry of cannabis. Comprehensive natural products II
  • A Hazekamp
  • J T Fischedick
  • M L Díez
  • A Lubbe
  • R L Ruhaak
Measurement uncertainty: a reintroduction. Sistema Interamericano de Metrologia
<https://doi.org/10.4224/40001835>
  • A Possolo
  • J Meija