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2019 Cannabis Patent Review I: Extraction and Purification

This is the first in a series of updated reports on recently granted U.S. patents in various areas of cannabis technology. Each installment in this series will include a brief description of the granted claims and application information for recent U.S. patents, in order to provide a nonexhaustive survey of new U.S. patents in a particular area. The reports in this series offer no opinions as to the scope or ultimate validity or patentability of any of the claims in the patents presented. The law presumes that granted U.S. patents are valid. A defendant in a patent infringement action may challenge validity in the U.S. district courts, and any party may request review of patentability in special proceedings at the U.S. Patent and Trademark Office.

One of the more active areas in the patenting of cannabis technology in 2019 is the related fields of cannabis extraction and cannabinoid purification. Cannabis operators now must educate themselves and navigate an emerging landscape of U.S. cannabis extraction and purification patents for freedom to operate, while also looking for opportunities to patent their own innovations. So far in 2019, the U.S. Patent and Trademark Office (USPTO) has granted over 30 patents with claims directed to cannabis extraction technologies and many others related to distillation of cannabinoid components and techniques for obtaining active compounds from marijuana and hemp. Dozens more are pending.

A review of the USPTO files for recently issued cannabis extraction and purification patents reveals the following trends in examination and gives insight into this rapidly expanding area of cannabis IP:

  • examination of claims and prior art searching is inconsistent and varies significantly by examiner;
  • many patent applicants are submitting little, if any, prior art to the USPTO as part of their duty to disclose;
  • the level of sophistication of patent counsel and patent drafting varies more than in other mature industries, such as pharmaceuticals;
  • by comparison to related industries, such as pharmaceuticals, there is less supporting data and fewer working examples contained in patent specifications in the cannabis industry; and
  • USPTO examiner searches and the applicants’ prior art submissions do not appear to be identifying much nonpatent literature on the extraction of cannabis and purification of cannabinoids, although surely such public prior art information exists.

Nerd alert! We are about to get into the weeds on some recently granted U.S. patents in the area of cannabis extractions and purifications. The scope of recently granted patent claims in this area varies from conventional extraction processes applied to cannabis and the purification of cannabinoids to cannabinoid-specific techniques developed to solve the problems unique to isolating and/or purifying components from the complex mixtures found in cannabis.

Alcohol Extraction, Distillation and Crystallization

U.S. Patent Nos. 10,413,845 and 10,414,709 were issued on September 17, 2019, to Socati Technologies of Tumwater, Washington. The claims of the ‘709 and ‘845 patents recite a method of isolating cannabinoids (such as THC or CBD) from cannabis by extracting cannabis with a C3-8 alcohol, evaporating the solvent, distilling the extract and crystallizing (or “winterizing”) the cannabinoid. The sole claim of the ‘845 patent reads as follows (emphasis added):

  1. A method of isolating tetrahydrocannabinol, a terpene, or cannabidiol from hemp or cannabis, the method consisting essentially of:
  1. extracting hemp or cannabis with a solvent selected from the group consisting of propanol, isopropanol, butanol, pentanol, hexanol, heptanol, and octanol to produce an extract consisting essentially of an extracted hemp or cannabis consisting essentially of tetrahydrocannabinol, a terpene, or cannabidiol;
  2. evaporating the solvent portion of the extract to generate a substantially solvent-free extract consisting essentially of the tetrahydrocannabinol, terpene or cannabidiol;
  3. distilling the substantially solvent-free extract to isolate the tetrahydrocannabinol, the terpene or the CBD, and
  4. crystallizing the distilled, isolated tetrahydrocannabinol, terpene or cannabidiol to produce a crystallized, isolated tetrahydrocannabinol, terpene or cannabidiol.

Freeze Dry and Extract

U.S. Patent No. 10,307,447 was issued on June 4, 2019, to Stephen Goldner of West Bloomfield, Michigan. The claims of the ‘447 patent recite a process of freeze drying and rupturing cannabis plant cells prior to CO2 extraction and isolation. Claim 1 of the ‘447 patent reads as follows (emphasis added):

  1. A process consisting essentially of:

rupturing plant cells of cannabis by freeze-drying the cannabis in order to expose or release one or more cannabinoids in the plant cells of the cannabis;

after rupturing the cannabis plant cells, extracting one or more of the cannabinoids from the cannabis by pressurizing the cannabis in a pressure vessel with along with supercritical carbon dioxide, the supercritical carbon dioxide dissolving the one or more cannabinoids, followed by depressurizing the cannabis in the pressure vessel, wherein the depressurizing precipitates the one or more cannabinoids out of the supercritical carbon dioxide;

isolating the one or more cannabinoids that precipitated from the supercritical carbon dioxide; and

wherein the freeze drying is performed below the triple point of water.

Two-Solvent Chromatography Purification

U.S. Patent No. 10,239,808 was issued on March 26, 2019, to Canopy Holdings, LLC of Littleton, Colorado. The claims of the ‘808 patent recite a two-solvent silica gel chromatography method for cannabinoid purification. Claim 1 of the ’808 patent reads as follows (emphasis added):

  1. A method of removing one or more cannabis compounds from a cannabis oil, the method comprising:

obtaining a column packed with a normal phase particulate, wherein the normal phase is a silica gel stationary phase particulate;

adding cannabis oil to the packed column;

adding a first eluent to the packed column, wherein the first eluent added totals between one and eleven column volumes (CVs), 2 to 7 CVs, or 4 to 6 CVs;

adding a second eluent to the packed column;

collecting at least two eluate fractions comprising one or more compounds; and

evaporating solvent from at least a subset of the at least two fractions to form a composition.

THC-A Heptane Extraction and Purification

U.S. Patent Nos. 10,059,684 and 10,246,431 were issued on August 8, 2018, and April 2, 2019, respectively, to AXIM Biotechnologies, Inc. of New York, New York. The claims of the ‘684 and ‘431 patents recite a method for separating THC-A from cannabis by heptane extraction followed by separation using basic sodium chloride solution. The sole claim of the ‘684 patent reads as follows (emphasis added):

  1. A method for producing Δ9-THC consisting essentially of:

extracting Δ9-THC carboxylic acid from cannabis flowers using heptane to obtain a heptane extract;

filtering the heptane extract to remove solid plant matter from the cannabis flowers; and

separating the Δ9-THC carboxylic acid from the heptane extract using sodium chloride water and then adjusting the pH to a pH range of 13.2 to 13.4 using magnesium chloride;

wherein the extracting of the Δ9-THC carboxylic acid from the heptane results in the formation of three layers consisting of a first organic layer, a second oily layer, and third aqueous layer.

Mechanical Trichome Separation

U.S. Patent No. 10,300,494 was issued on May 28, 2019, to Tetragrow, Inc. of Calistoga, California. The claims of the ‘494 patent recite a method for trichome separation from cannabis by agitation and then floatation of the removed trichomes in water. Claim 1 of the ‘494 patent reads as follows (emphasis added):

  1. A method of trichome separation from plants, the method comprising the steps of:

a. obtaining a trichome bearing plant material,

b. agitating the plant material,

d. [sic] introducing the plant material in fluid having a density of at least about 1.01 gm per cc to float the trichomes on the fluid,

e. removing the floating trichomes,

f. rinsing the removed trichomes to remove a residue of the fluid, and

g. drying the rinsed trichomes.

Ethanol Extraction and Brine Washing Process

U.S. Patent No. 10,406,453 was issued on September 10, 2019, to NextLeaf Solutions Ltd. of Vancouver, Canada. The claims of the ‘453 patent recite an extraction process involving an ethanol extraction followed by evaporation of ethanol and washing the resulting oil with brine. Claim 1 of the ‘453 patent reads as follows (emphasis added):

  1. A process for extracting cannabinoids from raw cannabis plant material comprising the steps of:

adding ethanol to dried and ground cannabis plant material to form an initial mixture;

centrifuging the initial mixture to separate a crude oil and ethanol mixture from the initial mixture;

treating the crude oil and ethanol mixture with charcoal particles, bentonite clay particles and magnesium oxide particles to remove unwanted components therefrom;

evaporating ethanol from the treated crude oil and ethanol mixture to leave oil; washing the oil with brine;

heating the brine-washed oil to convert THCa (tetrahydrocannabinolic acid) in the brine-washed oil into THC (tetrahydrocannabinol), resulting in decarboxylated oil; and

distilling the decarboxylated oil to obtain cannabinoids.

There is value in understanding the patent landscape for any area of growing innovation and investment, both as a means for understanding the subject matter protected by existing patents and as a tool for identifying patentable technology within your own company’s products and processes. Increased patent activity within the rapidly growing cannabis industry is creating a crowded landscape in certain areas, such as cannabis extractions and cannabinoid purification. Understanding the emerging cannabis patent landscape around key technologies is critical to evaluating mergers and acquisitions in the industry and to establishing licensing and supply relationships.


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