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trends in

Melanie Ooi, Gregor Steinhorn, and Manu Caddie

The Next Generation of Measurement Technology for
Medicinal Cannabis Production

cross the globe, legislation surrounding the application of cannabinoid compounds towards human
health is gaining momentum. Corresponding with
new regulations is a dramatic increase in cannabinoid-based
treatment options-from just a few drugs
in the early 2000s to now over 300 medical products currently in human trials
for ailments such as post-traumatic stress
disorder, nervous system degeneration, depression, epileptic seizures, Parkinson's
disease, multiple sclerosis and schizophrenia. Consumption of medicinal cannabis is
currently legal in over 40 countries and 33
states in the US, with the global sector estimated by some industry analysts to be
worth over USD 62.6 billion by 2024 [1].
Legalization of medicinal cannabis is under consideration in over a dozen other
countries, and more jurisdictions can be
expected to follow suit if the evidence for
efficacy of medicinal cannabis increases.
The Cannabis sativa plant includes a variety of compounds such as cannabinoids,
terpenes and phenolic compounds [2]. Cannabinoids and terpenes largely concentrate
on the secretory cavity of the glandular trichomes of female flowers. There are over
150 different cannabinoid compounds
that have been identified within the Cannabis sativa plant, and the concentration of
these compounds depends on tissue type,
age, variety, growth conditions (nutrition,
humidity, light level), harvest time and
storage conditions [3]. While the female
flower trichomes are of greatest production interest, the leaves and stems may also
be harvested based on the specific chemical
compound of pharmacological interest. Fig.
1 shows the Cannabis sativa plant.
Cannabinoids begin as Cannabigerol Acid, or CBGA, the
precursor to all other cannabinoids, and undergo a synthetization process to transform their chemical structure into
June 2020

other compounds such as THCA (Delta-9-Tetrahydrocannabinolic Acid). The most well-recognized cannabinoid compound
is probably THC, which has psychoactive properties that contribute to its popularity in recreational use. However, the
other most common cannabinoid in most varieties is cannabidiol or CBD, which is a non-psychoactive compound and
also has a range of proven medicinal benefits. In general, medicinal cannabis growers would normally select strains that
are balanced between THC and CBD, THC-dominant or CBDdominant, while recreational cannabis growers prefer strains
that are only THC-dominant. Upon harvest, medicinal cannabis products are chemically analyzed in laboratories to profile
their chemical compounds to determine the concentration of
cannabinoids and terpenes. The value of a crop intended for
pharmaceuticals is based on both the yield and consistency of
chemicals in the plant, as well as the absence of foreign contaminants (pests, disease, heavy metals, pesticides and other
microbiological organisms), and determines how much effort
is necessary during extraction to achieve the desired composition of the final pharmaceutical product.
Unfortunately, most chemical testing is expensive and performed only at the harvest stage of production as it is designed
to ensure compliance with quality standards for pharmaceutical manufacturing. This practice provides little support to the
grower because at this stage, the test results come too late to alter any decisions that led to the production of the crop. Thus,
the industry needs reliable plant tests not only in dedicated
quality control labs, but also within the cannabis production
cycle in order to support cultivation management, optimize
yields and improve the quality and consistency of their produce. This requires rapid testing capability in or close to the
cultivation facility. Fig. 2 provides an overview of the possible
testing needs during the production cycle.
Successful medicinal cannabis production relies on the
selection of the best cultivars to produce plant material
for a specific pharmaceutical product. Cannabis producers will select and purchase cultivars from companies that
have breeding programs to produce cultivars with specific chemical profiles. The selection criteria are based on
phenotypic and chemotypic characteristics (i.e., different cultivars produce different cannabinoid profiles), and some are
more consistent than others and resistant to environmental

IEEE Instrumentation & Measurement Magazine 63
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