ABSTRACT: This overview covers a wide range of cannabis topics, initially examining issues indispensaries and self-administration, plus regulatory requirements for production of cannabis-based medicines, particularly the Food and Drug Administration “Botanical Guidance.” The remainder pertains to various cannabis controversies that certainly require closer examination if the scientiﬁc, consumer, and governmental stakeholders are ever to reach consensus on safety issues, speciﬁcally: whether botanical cannabis displays herbal synergy of its components, pharmacokinetics of cannabisand dose titration, whether cannabis medicines produce cyclo-oxygenase inhibition, cannabis-drug interactions, and cytochrome P450 issues, whether cannabis randomized clinical trials are properly blinded, combatting the placebo effect in those trials via new approaches, the drug abuse liability (DAL) of cannabis-based medicines and their regulatory scheduling, their effects on cognitive function and psychiatric sequelae, immunological effects, cannabis and driving safety, youth usage, issues related to cannabis smoking and vaporization, cannabis concentrates and vape-pens, and laboratory analysis for contamination with bacteria and heavy metals. Finally, the issue of pesticide usage on cannabis crops is addressed. New and disturbing data on pesticide residues in legal cannabis products in Washington State are presented with the observation of an 84.6% contamination rate including potentially neurotoxic and carcinogenic agents. With ongoing developments in legalization of cannabis in medical and recreational settings, numerous scientiﬁc, safety, and public health issues remain.
Project CBD received this inquiry from a Canadian citizen:
“I'm wondering the best way to use CBD from flowers. Smoking a high CBD strain (Charlottes Web) still got me stoned despite having very minimal THC. I am thinking about buying a Volcano Digital Vaporizer, but I want to make sure I can effectively get CBD. So, can I vaporize the THC out of cannabis flowers? Can I vaporize at 157°C and let the THC escape and then vaporize between 160°C-180°C to get just the CBD only? Or is that an impossibility and you have to have both THC and CBD together? Much appreciated, thanks for your time!”
Project CBD responds:
"Thank you for contacting Project CBD. Check out the boiling point chart on various cannabinoids and terpenes below. THC boils at a slightly lower temperature than CBD. However, when vaporizing a strain that contains any THC at all, you still may absorb some effects. Here is why:
CBD doesn't have a clear set boiling point. It's more in the 160-180°C range. While THC is listed at 157 Celsius, the fact is that both will sublimate off at a lower temperature. This is similar to the way the snow disappears on a really cold day when the humidity is low and there is sun or wind—the flakes just go directly from solid to gas (water vapor) even though the temperature is seemingly too low for melting.
As great of a product as a Volcano is, it is not perfect. The digital Volcano model provides tolerances at +/- 0.5 degrees Celsius. Nevertheless, beyond that, there are marked temperature gradients in the chamber—one area will be quite hot compared to another, particularly if the herbal material is large or clumped. Thus, you cannot ensure that the herbal material will be exposed to uniform temperatures required for fractionation. Therefore, if there is THC present in the cannabis you are vaporizing, some will likely remain in the vapor even after its boiling point is exceeded.
Separating out cannabinoids from one another is practical only with industrial strength techniques, such as centrifugal partition chromatography. It can't be done in the kitchen, unfortunately. So your best bet would be to try another strain if you do not like the psychoactivity. Cannatonic (ACDC) is one strain that can have an 18:1 CBD/THC profile. Users generally find that they can also develop a tolerance to psychoactivity over time.
I hope this is helpful. Let me know if you have further questions."
Another reader from Poland had a related question on decarboxylation from CBDA to CBD:
"At what temperature I should heat cannabis to decarboxylated CBDA to CBD? 80 degrees Celsius? 120 degrees?"
Project CBD's Response:
"130°C is the boiling point for CBDA, but the boiling point is different than decarboxylation. There are a couple of issues. Decarboxylation happens at different temperatures at different speeds. You lose some of the plant's compounds when you bake cannabis in the oven, for example. It can be done more slowly at 80°C, but takes several hours. Cannabinoids and other compounds in the plant will sublimate off at a lower temperature. We are not sure of the ideal method for you in a home situation, so it will require some experimentation. You could try using a jar placed in water. Heat the water to 80 degrees Celsius for 4 hours, and check on it to ensure the temperature remains the same.
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