Solving the soluble puzzle for cannabis edibles

Many new products within the cannabis food and beverage industry are likely to launch once permits start being issued by Health Canada, expected in late 2019, exposing Canadians to hundreds of new formulations of consumer-packaged goods containing cannabis.

Canadians are in the midst of playing catch-up to a recreational cannabis industry that has been legal for several years in other jurisdictions—including Washington, Colorado and, more recently, California—that have already worked through some of the technical challenges. For example, edibles and extractions exceeded flower sales in California in 2018 and a recent ArcView and BDS Analytics report estimates edibles sales by 2022 will be worth US$4.1 billion.

 

 

What to do since cannabinoids and water simply don’t mix

THC and other cannabinoids are all, to a varying degree, oil- and alcohol-soluble molecules that don’t mix with water. THC is easily extracted in oil and anyone who has made pot brownies by creating a sauté of toasted dried cannabis and butter is taking advantage of that principle. The heating of the cannabis and immersion in the oil decarboxylates the THC(A) and CBD(A) molecules into THC and CDB, which, in turn, can bind to a person’s cannabinoid receptors as it gets metabolized by the body into 11-hydroxy-THC and then into 11-nor-9-carboxy-THC.

The oil in the aforementioned butter binds to the oil-loving cannabinoids. The high content of water in butter causes some of the hydrophilic molecules, such as chlorophyll, to be drawn from the cannabis, thereby giving canna-butter its distinctive pale green colour and bitter taste.

“Cannabinoids are fat-soluble and this is why they [edibles] have lived in the world in the [black] market as sweets and candies to combat the bitter taste of canna-butter,” says Jeremy Goldstein, chief operating officer and co-founder of Stillwater Brands, a Denver-based processor, manufacturer and distributor of soluble cannabinoid-infused, consumer-packaged goods and commercial ingredients.

While canna-butter will work for products that can use oil and plenty of sugar in their formulations, Canada’s prohibitions on sugar, colours or sweeteners in products means a move from a simpler preparation to a more complex one. Additionally, products will be launching that are water-soluble only (think cannabis water), bringing new challenges to deliver those same lipid-loving THC and CBD molecules in a hydrophilic solution.

Canadians are in the midst of playing catch-up to a recreational cannabis industry that has been legal for several years in other jurisdictions

Stillwater produces Ripple, a single-serve powder pouch of dissolvable, no-calorie THC and CDB powder that has been exclusively licensed in Canada by The Green Organic Dutchman.

Emulsions offer a solubility fix for edibles

Solubility of an insoluble substance is something that has been solved in the food and pharmaceutical industries many times with the aid of emulsions, a dispersion of particles within a non-miscible solution, including milk (an oil in water emulsion) and margarine (a water in oil emulsion). The expense and energy requirements to create emulsions come down to the desired particle size and creation methodology.

Emulsions are generally categorized as macro-emulsions, micro-emulsions and nano-emulsions. Alexey Peshkovsky, PhD is co-founderpresident and chief science officer of Industrial Sonomechanics LLC, a research and development, equipment design and process consulting firm specializing in high-intensity ultrasonic technology for liquid treatment. Having started its work to solve the solubility problems for the enterprise pharmaceutical industry more than a decade ago, Peshkovsky explains the process of ingesting a rough macro-emulsion like canna-butter and converting it to a water-soluble substance the body can process and absorb.

“When you ingest monoglycerides like cannabis, they have to travel through your stomach to reach your small intestine,” he says. “Once they have reached the small intestine, the body starts the process of breaking down and converting these molecules into mixed micelles, essentially nano-emulsion droplets of about 10 nanometres (nm) in size, but while it’s doing this, it is moving out of your system,” he notes.

Peshkovsky explains, however, why this process hinders bioavailability. “You need to make these micelles first, and that process is slow and gradual. Much of it is lost as it travels through and out of the small intestine, and what is absorbed is not absorbed all at once,” he says. “That is why the bioavailability is low, because it takes forever to do this conversion and so most is just lost. You are slowly making those (micelles) as you go along, some are being absorbed while others are still being converted. That is why there is a slow and unpredictable curve of the effects,” he adds.

That slow and uneven curve is what causes the 30-minute delay to the onset of the effects of the ingested cannabis and, perhaps, what causes some users to over-consume, resulting in a much higher dosage than expected.

Enter emulsions. “Nano-emulsions mimic those micelles,” Peshkovsky says, commenting on the benefit of emulsions. “They are essentially suspensions of these micelles that arrive in the lower intestine in ready-to-be absorbed form, meaning the bioavailability is higher and the onset reaction is faster,” he explains.

What are emulsions?

A macro-emulsion is simplest to create and has the largest particle size, at greater than 100 nm, and because it is above the threshold that the eye can perceive (50 nm), it will not appear translucent. Anyone who has made a salad dressing from oil and vinegar by vigorous shaking has seen an example of a macro-emulsion. Macro-emulsions are unstable and will return to separate layers, sometimes with a mixed layer in between.

Both nano- and micro-emulsions can appear clear, as both particle sizes can be greater than 50 nm, but the prefix of nano or micro, in this case, is deceiving. In scientific terms micro refers to a factor of 10^-6 (millionth) and nano refers to a factor of 10^-9 (billionth), but the size of nano-emulsion particles can actually be larger than the particles within a micro-emulsion.

Increasing bioavailability of cannabis allows users to have an earlier onset and higher absorption rate of cannabinoids.

Nano-emulsions are thermodynamically unstable while micro-emulsions are thermodynamically stable—meaning a micro-emulsion can be shaken or heated, but will eventually return to its original state regardless of creation methodology, which is primarily chemical. The surfactants (for example oleic acid, Tween 80 and Cremophor RH 40 in the case of this patent), encapsulant and water, will spontaneously form into a micro-emulsion, while nano-emulsions have to be created mechanically. The number and quantity of surfactants used in the mechanical preparation of the nano-emulsions is typically 10 times less. A popular surfactant for nano-emulsions in the food world is Quillaja Saponaria (soapbark tree).

Increasing bioavailability of cannabis allows users to have an earlier onset and higher absorption rate of cannabinoids. “There are no specific studies that look at the increase in bioavailability of cannabis (prepared as a nano-emulsion), but by looking at the literature and studies, it varies between a factor of three and nine,” says Peshkovsky, adding that his personal view is that “some people will report more, but I would be sceptical.”

When the cannabis industry began looking at edibles and emulsions about three years ago, Industrial Sonomechanics started making changes and related work now accounts for the majority of its clientele and inquiries. Its machines produce scale to enterprise levels, pumping out 125,000 doses of nano-emulsions at a concentration of 50 nm/ml per hour. These transparent doses can be used in many different products for which maintaining clarity and increased bioavailabilty are desired.

Le Herbe is another Colorado-based cannabis edible product manufacturer that sees the benefit in increasing bioavailability in its products. While Stillwater Brands has set its sights on producing a soluble powder, Le Herbe has focused on introducing micro-emulsions and nano-emulsions to water-based products like cold brew coffee and cannabis water.

Vincent Cali, a representative from Le Herbe, notes in an email response: “Our research has shown that most edible products do not have emulsions, and upon consumption, humans only consume four percent of the stated dosage (bioavailability),” Cali reports, claiming that his company’s emulsion formulations and data suggest a 10-fold increase.

While both Stillwater and Le Herbe opt not to provide details on the methods used for the water-soluble powder-containing cannabinoids each produces, a search of patents turns up a similar method. In this patent, held in part by cannabis social activist Ed Rosenthal, cannabis oil is added to maltodextrin (starch powder) and dried to form a water-soluble powder. Another proposed methodology uses nano-emulsions spray dried onto a water-soluble encapsulation matrix of polysaccharides, which is then freeze-dried and milled.

Biggest challenges to creating cannabinoid-based ingredients

While the methodologies vary, it is inevitably the optimization and scaling of processes that represents the biggest challenge to producers creating cannabinoid-based ingredient lines, albeit a challenge that producers in the legal jurisdictions have a head-start on solving.

When the cannabis industry began looking at edibles and emulsions about three years ago, Industrial Sonomechanics started making changes and related work now accounts for the majority of its clientele and inquiries.

“There are many ways to skin this cat,” Stillwater’s Jeremy Goldstein suggests of solubility. “The key thing is that the process started off completely manual. In the beginning, it took us five days to create a batch of our powder,” Goldstein says of his company’s experience, but adds it is now completed in the matter of hours.

Looking to read a bit more about methodologies that might come into play? Feel free. Additional methodologies to be considered for the mechanical creation of nano-emulsions include the following:

• sonication;
  • high-pressure homogenization;
  • microfluidization;
  • phase inversion method (heating or cooling);
  • spontaneous emulsification; and
  • solvent evaporation technique.

 

Blake Medulan, whose website is www.cannaresultant.com, is currently a cannabis consultant operating out of Toronto and Quebec.