Patent Grant
10383892
The present disclosure relates to decarboxylated cannabis resins and use of the decarboxylated resins directly as medicines or natural health products, or as raw materials for making cannabis-derived products, including pharmaceutical products, pharmaceutical formulations and natural health products. The disclosure also relates to products and compositions comprising the decarboxylated cannabis resins. Also disclosed are methods of making the decarboxylated cannabis resins using microwave extraction and decarboxylation.
Cannabis is a genus of flowering plants in the family Cannabaceae. Three species may be recognized (Cannabis sativa, Cannabis indica and Cannabis ruderalis). Cannabis spp. contains a highly complex mixture of compounds, up to 568 unique molecules identified to date (Pertwee, R. G. e., Handbook of cannabis. Oxford University Press: Oxford, 2014). Cannabinoids are the most noteworthy compounds found in Cannabis spp. Among these compounds, Δ9-tetrahydrocannabinol (Δ9-THC), cannabinol (CBN), and cannabinodiol (CBDL) are known to be psychoactive (Pertwee, R. G. e., Handbook of cannabis. Oxford University Press: Oxford, 2014). Other cannabinoids such as cannabidiol (CBD), which is a non-psychoactive compound, exert their physiological effects through a variety of receptors including adrenergic and cannabinoid receptors (Pertwee, R. G. e., Handbook of cannabis. Oxford University Press: Oxford, 2014). Cannabinoid receptors (CB1 and CB2) belong to G-protein coupled receptors (GPCRs) (Cottone, E.; Pomatto, V.; Cerri, F.; Campantico, E.; Mackie, K.; Delpero, M.; Guastalla, A.; Dati, C.; Bovolin, P.; Franzoni, M. F. Cannabinoid receptors are widely expressed in goldfish: molecular cloning of a CB2-like receptor and evaluation of CB1 and CB2 mRNA expression profiles in different organs. Fish Physiology and Biochemistry 2013, 39 (5), 1287-1296). Phytocannabinoids produced by Cannabis spp. plants as well as endocannabinoids produced in our body bind to these receptors. Patients consume medical cannabis for the treatment of or seek relief from a variety of clinical conditions including pain, anxiety, epileptic seizures, nausea, and appetite stimulation (Galal, A. M.; Slade, D.; Gul, W.; El-Alfy, A. T.; Ferreira, D.; Elsohly, M. A. Naturally occurring and related synthetic cannabinoids and their potential therapeutic applications. Recent patents on CNS drug discovery 2009, 4 (2), 112 and Downer, E. J.; Campbell, V. A. Phytocannabinoids, CNS cells and development: A dead issue? Phytocannabinoids have neurotoxic properties. Drug and Alcohol Review 2010, 29 (1), 91-98). It is also known that cannabinoids and endocannabinoids affect the development and maturation of neural cells in early life (Downer, E. J.; Campbell, V. A. Phytocannabinoids, CNS cells and development: A dead issue? Phytocannabinoids have neurotoxic properties. Drug and Alcohol Review 2010, 29 (1), 91-98). Cannabinoid-like compounds isolated from flax have also shown anti-inflammatory properties (Styrczewska, M.; Kulma, A.; Ratajczak, K.; Amarowicz, R.; Szopa, J. Cannabinoid-like anti-inflammatory compounds from flax fiber. Cellular & Molecular Biology Letters 2012, 17 (3), 479-499).
Most cannabinoids are concentrated in a viscous resin produced in structures of the cannabis plant known as glandular trichomes. At least 113 different cannabinoids have been isolated from the cannabis plant, the most common being Δ9-tetrahydrocannabinolic acid (Δ9-THC-A) which is the non-active precursor of the psychoactive Δ9-tetrahydrocannabinol (Δ9-THC).
Δ9-THC-A is found in variable quantities in fresh, undried cannabis, but is progressively decarboxylated to Δ9-THC with drying, and especially under intense heating such as when cannabis is smoked or cooked into cannabis edibles.
Δ9-THC is not the only substance obtained from cannabis with therapeutic benefits to people. For example, studies have shown that cannabidiol (CBD), another major constituent of some strains of cannabis, has been found to be anxiolytic and to have antipsychotic properties, and may be neuroprotective in humans.
Decarboxylation is a chemical reaction that releases carbon dioxide and generates neutral cannabinoids. In one example in cannabis, the non-psychoactive Δ9-THC-A can be converted to psychoactive Δ9-THC by decarboxylation.
There is a need to produce a cannabis resin comprising cannabinoids that are decarboxylated. The cannabis resins or extracts known in the art may not be consistently and fully decarboxylated and comprise significant proportions of THCA and CBDA. For example, see WO 2014/159688. The cannabis extracts or resins of the art are for use, for example, in vaporization, infusion into edible matrices, and inhalation via electronic inhalation devices. Accordingly, the extracts and resins of the art comprise predominantly THCA and/or CBDA, as opposed to their decarboxylated counterparts (THC and CBD respectively), and it is only after heating the extracts and resins via vaporization or cooking in edible matrices that decarboxylation occurs (i.e. only after heating the extracts and resins that the cannabinoids are decarboxylated into their active forms). As the cannabis resins of the present disclosure comprise decarboxylated therapeutically active cannabinoids, they may be used directly. For example, the cannabis resins of the present disclosure may be used directly in therapy or used to develop various cannabis formulations for pharmaceutical products that do not need to be further heated (i.e. decarboxylated) into therapeutically active forms.
Many people may be reluctant to use cannabis (either as a medicine or natural health product) if it has to be “smoked” or heated (i.e. “vaping”). This may be because there are negative perceptions to smoking and vaping, especially in the older generation. Many people may be more accepting of cannabis if it is in a form that is more conventional (i.e. tablet form, or other conventional forms of medicine). In order, to produce conventional forms of cannabis for use as a medicine or natural health product, the cannabinoids in the product must be decarboxylated.
There is also a need to develop an efficient method of extracting and decarboxylating cannabinoids from cannabis.
To date the simplest mechanism to perform decarboxylation of cannabinoid acids is by heating. Other processes of decarboxylation require toxic solvents. In these systems, a distillation process such as fractional distillation may be employed to separate the organic solvents from the cannabis extract after decarboxylation.
In addition to decarboxylation, extraction of cannabinoids from the plant material is required. Extraction is most often done prior to decarboxylation. Mechanisms of extraction of cannabinoids such as Δ9-THCA and CBDA from cannabis that are known include sonication, reflux (Soxhlet) extraction and supercritical fluid extraction (SFE). For example, U.S. Pat. No. 9,044,390 describes a fractional SFE process of contacting cannabis plant material with a supercritical fluid solvent system at a pressure between about 750 psi and 25,000 psi, and at a temperature between about −15° C. and 200° C.
With the rise in the authorized use of cannabis for medical, therapeutic and recreational purposes, there is an increasing need for a reproducible method for obtaining a consistent active cannabinoid-comprising resin with known efficacy and to optimize production and recovery of active decarboxylated cannabinoids. With increasing demand and potential uses, there is also a need for a method that can be easily scaled-up for manufacture of commercial pharmaceutical preparations, natural health product preparations or recreational use preparations.
The present disclosure provides a decarboxylated cannabis resin. The decarboxylated cannabis resin comprises the cannabinoid profile of the plant from which the resin was extracted, but the cannabinoids are decarboxylated. The cannabinoids are at least 90%-100% decarboxylated (i.e. 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100%, or any fraction thereof, e.g. 93.3% decarboxylated). Unlike some of the cannabis resins of the prior art, the decarboxylated cannabis resin of the present disclosure can be used directly, for example, in therapy or can be used as a raw material to develop various pharmaceutical formulations that do not need to undergo heating for decarboxylation into therapeutically active forms.
In addition to the above decarboxylated cannabinoids, other chemicals found in Cannabis spp. and soluble in the solvent used, are found in the resin. Such compounds may include, for example, terpenes, fatty acids, chlorophyll, flavonoids, and other compounds. Some of the compounds may undergo chemical transformation due to the processes used for extraction and decarboxylation. In some embodiments, THC and/or CBD are the major components of the decarboxylated cannabis resin.
The present disclosure also provides an improved method of extracting and decarboxylating cannabinoids from cannabis plant material, the method comprising decarboxylating cannabis plant material before, during or after extraction using microwave technology.
In some embodiments the method comprises: chopping down or grinding down the cannabis plant material into smaller pieces to form cannabis plant material of a size and form suitable for extraction; extracting cannabinoids from the broken down cannabis plant material by contacting the broken down cannabis plant material with a solvent in a mixture to extract cannabinoids from the cannabis plant material and decarboxylating the cannabinoids in the mixture by subjecting the mixture to microwaves to form decarboxylated cannabinoids.
In some embodiments, the extraction and decarboxylation steps are done in one step, by exposing the plant material to a suitable solvent, (e.g. pharmaceutically acceptable solvent, for instance a solvent selected from the group of solvents consisting of: 80-100% ethanol (for example, 80%, 85%, 90%, 95%, 97%, 98%, 100%, and any integer or fraction of the integer thereof), ethylene glycol, isopropanol or a combination of similar solvents, and subjecting the plant material in the solvent to microwaves sufficient to obtain the desired decarboxylated cannabinoid comprising resin. If 100% decarboxylation is not required, the duration of the microwaving step can be adjusted to obtain the desired degree of decarboxylated cannabinoids in the resin. In some embodiments, the plant material in the solvent is placed in a microwave. In some embodiments it is subjected to microwaves for a time and/or at a pressure and/or at a temperature sufficient to produce desired decarboxylated (biologically active) cannabinoid comprising resin. In some embodiments, the chopping down, extraction and decarboxylation are done in one step.
In some embodiments when the extraction and decarboxylation steps are done in one step, the broken down cannabis plant material is suspended (for example, by stirring, shaking or agitation) in a solvent and subjected to microwaves resulting in an extracted and decarboxylated cannabis resin.
An embodiment of the disclosure is a decarboxylated cannabis resin, wherein the resin comprises decarboxylated cannabinoids from a Cannabis spp. plant, such that Δ9-tetrahydrocannabinolic acid (Δ9-THCA) and cannabidiolic acid (CBDA) cannabinoids in the plant are each independently 90% to 100% decarboxylated to yield Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) respectively in the resin. The range of 90% to 100% decarboxylation includes any integer or fraction of an integer in this range, for example 90%, 88.4%, and 100%. The decarboxylated cannabis resin may further comprise cannabinol (CBN), other decarboxylated cannabinoids, or any compounds (for example, terpenes, chlorophyll), including for example, the compounds found on Table 32.
The decarboxylated cannabis resin may comprise less than 5% solvent by weight or by volume, or it may be is substantially free of solvent.
An embodiment of the disclosure is a pharmaceutical composition comprising (i) the decarboxylated cannabis resin of the disclosure and (ii) a suitable pharmaceutically acceptable carrier or excipient.
Another embodiment of the disclosure is a natural health product comprising the decarboxylated cannabis resin of the disclosure.
Another embodiment of the disclosure is a method of extracting and decarboxylating cannabinoids from plant material, the method comprising: (i) extracting cannabinoids from the Cannabis plant material by contacting the Cannabis plant material with a solvent to extract cannabinoids from the Cannabis plant material, the extract of Cannabis comprising the solvent and cannabinoids; and (ii) decarboxylating the cannabinoids in (a) the plant material and (b) the extract comprising cannabinoids by subjecting the plant material and extract to microwaves at temperature of about 100-200° C. in a sealed container and for a time period sufficient to form the corresponding decarboxylated cannabinoids in the extract. The temperature may be any integer or fraction of an integer in the range of 100-200° C., for example 103° C., 175.5° C., and 200° C.
In some embodiments, the plant material is broken down to form cannabis plant material of a size and form suitable for extraction before the extracting step.
In some embodiments, the extracting and decarboxylating occur concurrently.
In some embodiments, the cannabis plant material is suspended in the solvent by stirring or agitation.
In some embodiments, the solvent is selected from the group of solvents consisting of: 80-100% ethanol, ethylene glycol, isopropanol, and a combination of any of the above. The ratio of solvent to cannabis plant material may be such that the Cannabis plant material is submerged in the solvent in the sealed container.
In some embodiments, the time period is about 15-75 minutes depending on scale of the reaction.
In some embodiments, the temperature is about 130° C. to about 180° C., or about 150° C. to about 170° C.
In some embodiments, the microwaves have a frequency of about 2.45 GHz and a wavelength of about 1.22×108 nm.
In some embodiments, subjecting the plant material and extract to microwaves in the sealed container occurs under pressure of about 1-22 bar. The pressure may be any integer or fraction of an integer in the range of 1-22 bar, for example 1 bar, 15.5 bar and 18 bar.
In some embodiments the extracted and decarboxylated cannabinoids are recovered in the form of a cannabis resin or in the form of isolated compounds. For example, the decarboxylated cannabinoids may be recovered from the cannabis resin by separating (i) a single cannabinoid, (ii) a mixture of cannabinoids, (iii) a single compound or (iv) a mixture of compounds from the resin. The decarboxylated cannabinoids may be recovered using a Celite® and/or an activated charcoal carbon filter.
In some embodiments, the decarboxylated cannabinoids in the resin may be subjected to winterization for the removal of waxes.
In some embodiments, the cannabis plant material is dried prior to the breaking down step. In some embodiments, the cannabis plant material is dried cannabis.
In some embodiments, a further step of removing the solvent from the resin to obtain a substantially solvent-free decarboxylated cannabis resin is used.
In some embodiments, the cannabis plant material is trichomes, cannabis female inflorescence, flower bract, cannabis stalk, cannabis leaves, or combinations thereof.
In some embodiments, the solvent is removed from the resin.
An embodiment of the disclosure is the method of the disclosure done on a commercial scale.
An embodiment of the invention is the use of the cannabis resin of the disclosure in a natural health product or in a pharmaceutical product.
Additional aspects of the present application will be apparent in view of the description which follows. It should be understood, however, that the detailed description and the specific examples, while indicating embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure will become apparent to those skilled in the art from this detailed description.
Δ9-THC=Δ9-Tetrahydrocannabinol, CBD=Cannabidiol, CBN=Cannabinol, CBDL=Cannabinodiol, CBC=Cannabichromene, CBL=Cannabicyclol, CBE=Cannabielsoin, CBG=Cannabigerol, THV=Tetrahydrocannabivarin, CBDV=Cannabidivarin, CBCV=Cannabichromevarin, THCA=Tetrahydrocannabinolic acid, CBDA=Cannabidiolic acid, CBNA=Cannabinolic acid, CBCA=Cannabichromenic acid, CBLA=Cannabicyclolic acid, CBEA=Cannabielsoic acid, CBGA=Cannabigerolic acid, THCVA=Tetrahydrocannabivarinic acid, C1-THCRA=Tetrahydrocannabiorcolic acid, C4-THCA=C4-Tetrahydrocannabinolic acid, CBND=Cannabinodiol.
In order that the subject matter may be readily understood, embodiments are illustrated by way of examples in the accompanying drawings, in which:
As previously described, tetrahydrocannabinol (THC), or more precisely its main isomer Δ9-THC, is the principal psychoactive constituent (or cannabinoid) of cannabis. Unlike THC, its corresponding acid THC-A (or Δ9-THC-A for its main isomer) is a non-psychoactive cannabinoid found in raw and live cannabis.
Δ9-THC is only one of the family of compounds known as cannabinoids. For example, Δ8-THC is a double bond isomer of Δ9-THC and is a minor constituent of most varieties of cannabis. The major chemical difference between the two compounds is that Δ9-THC is easily oxidized to cannabinol (CBN) whereas Δ8-THC does not oxidize to cannabinol as it is very stable. Δ8-THC, for the most part, produces similar psychometric effects as does Δ9-THC, but is generally considered to be 50% less potent than Δ9-THC. On the other hand, CBD has no or limited psychometric activity on its own when administered to humans, however as discussed below CBD comprises other therapeutic qualities. In the cannabis plant, CBGA is a precursor and cannabinol (CBN), a metabolite of THC. As cannabis matures, THC gradually breaks down to CBN which also has psychoactive properties.
Turning to
The extracted and decarboxylated cannabinoids are optionally recovered. Recovery can include filtering the solvent from the extract of cannabis plant material to isolate the decarboxylated cannabinoids.
In some embodiments, the process comprises an extraction step before, during or after decarboxylation. In some embodiments, the process of the disclosure comprises more than one extraction step.
In some embodiments, the decarboxylation step can occur before, during or after extraction.
In an embodiment of the disclosure, a one-step method for extraction and decarboxylation is used, wherein the cannabis plant material (that is suitably prepared, e.g. optionally dried and broken down as described herein) is placed in a suitable extracting solvent (e.g. a pharmaceutically acceptable solvent such as ethanol, glycerol, and isopropanol, and other solvents as is known to those skilled in the art, kept in suspension or solution (e.g. by stirring, agitation, shaking or other means known to those skilled in the art) and subjected to microwave radiation while stirring at a temperature, pressure and time to obtain suitably extracted and decarboxylated cannabinoids that can be recovered for use as either a mixture or individual chemical components (e.g. for use as a therapeutic or pharmaceutical product). Further in some embodiments, the solvent can be food grade oil and/or a medium chain triglyceride, for example, coconut oil.
Such a method is more efficient in converting the cannabinoid acid into its decarboxylated form than other known methods of extraction and decarboxylation (such as simple heating).
Particularly,
Drying 102
At step 102, cannabis plant material can be dried to reduce water/moisture content. Herein, cannabis plant material encompasses any cannabis plant, including but not limited to Cannabis sativa, Cannabis indica and Cannabis ruderalis, and all subspecies thereof (for example, Cannabis sativa subspecies indica including the variants var. indica and var. kafiristanica), including wild or domesticated type Cannabis plants and also variants thereof, including cannabis chemovars (varieties characterized by virtue of chemical composition) which naturally contain different amounts of the individual cannabinoids and also plants which are the result of genetic crosses, self-crosses or hybrids thereof. The term “cannabis plant material” is to be interpreted accordingly as encompassing plant material derived from one or more cannabis plants. “Cannabis plant material” includes live or fresh cannabis and dried cannabis. In addition, any part of the cannabis plant may be used, including but not limited to trichomes, flower buds, flower bracts, leaves, stalk and any other plant part that may contain cannabinoids. Also, although the female plants may produce a higher concentration of cannabinoids than male plants, both female (including “feminized plants”) and male plants can be used.
Optional drying step 102 can be used to remove excess moisture from the cannabis plant material prior to the cannabis plant material undergoing extraction and decarboxylation. Removing water content from the cannabis plant material can help to provide even heating at later stages in the extraction and/or decarboxylation process. Alternatively, fresh cannabis plant material (e.g. from the plant directly) can be used for the subsequent break down, extraction and decarboxylation steps. Herein, drying of the cannabis plant material at step 102 can occur by any means, for example in an oven at temperatures in the range of 60-75 C, or similar conditions, or using a vacuum oven or similar conditions over several hours, for example 4 hours, or 6 hours or 8 hours, depending on the amount of moisture. During the drying process, when heating is employed using heating elements in the ovens or infrared heating among other processes, some of the cannabinoid carboxyl acids forms could be converted into their decarboxylated cannabinoid forms.
Break Down 104
At break down step 104, cannabis plant material can be broken down to produce a cannabis plant material of a size and form suitable for extraction and decarboxylation by subjecting to microwave heating.
Trichomes (i.e. resin glands) of the cannabis plant material are nearly microscopic, mushroom-like protrusions from the surface of the buds, fan leaves, and the stalk. While relatively complex, trichomes are comprised primarily of a stalk and a head. The production of cannabinoids such as THC occurs predominantly in the head of the trichome. Cannabinoids are concentrated in the trichomes of the plant. The trichome is built to easily shed from the cannabis plant material surface.
The term “a size and form suitable for extraction and decarboxylation” refers to a reduction in the particle size of the cannabis plant material fragments.
Herein, breakdown of the cannabis plant material at step 104 can occur by any mechanical means including by crushing, smashing, grinding, pulverizing, macerating, disintegration or equivalent processes as are known to those skilled in the art that reduce the cannabis plant material into small pieces suitable in size and form for extraction and/or decarboxylation.
In one example embodiment, sonication can also be used to loosen the cannabis plant material in contact with an appropriate solvent such as ethanol, and/or by breaking down cellular membranes making it suitable for extraction and/or decarboxylation. In another example embodiment, maceration can be performed with a mortar and pestle to produce a cannabis plant material of a size and form suitable for extraction and/or decarboxylation.
In certain embodiments, the cannabis plant material is reduced in size such that its particle size is within a range of 1 mm to 10 mm.
Extraction 106
Upon completion of break down step 104, extraction step 106 may be performed. It should be noted that extraction step 106 may occur as a separate step to decarboxylation step 108 either before or after decarboxylation step 108, or as will be described below, extraction step 106 and decarboxylation step 108 may occur concurrently. For the avoidance of doubt it should be understood that any extraction, including but not limited to sonication in the presence of a solvent, reflux (Soxhlet) extraction and supercritical fluid extraction (SFE) may occur before or after decarboxylation step 108. In addition, it should also be understood that break down (104), extraction (106) and decarboxylation (108) may also occur in one step.
In one embodiment, extraction step 106 can comprise contacting cannabinoids from the broken down cannabis material that is the product of break down step 104 with a solvent.
In some embodiments, the solvent treatment in extraction step 106 removes non-cannabinoid impurities to leave a substantially pure preparation of cannabinoids. It has been shown that non-polar, liquid solvents may be useful for this function. Suitable non-polar solvents therefore include essentially any non-polar solvents which are substantially less polar than the cannabinoids, such that impurities which are more polar than the cannabinoids are removed by treatment with the solvent. Filtration and other methods as is known to those skilled in the art can also be used to remove impurities.
Useful non-polar solvents include, but are not limited to, C5-C12 straight chain or branched chain alkanes, or carbonate esters of C1-C12 alcohols. The more volatile C5-C12 alkanes may be particularly useful, as they are more easily removed from the extract. Further, solvents that have been approved for use in pharmaceutical compositions, such as ethanol (e.g. 95% ethanol) may be particularly useful.
Particularly useful solvents include pentane, hexane, heptane, iso-octane and ethanol, and/or mixtures thereof or the like as is known to those skilled in the art.
In one embodiment of extraction step 106, broken down cannabis plant material can be added to a solvent and concurrently sonicated.
Herein, sonication refers to the application of ultrasonic vibration (e.g. >20 kHz) to fragment cells, macromolecules and membranes of the dried or undried cannabis plant material. Ultrasonic vibration can be provided by any means known in the art.
In one exemplary embodiment, sonication of a mixture of cannabis plant material and solvent can occur for 5-25 minutes at 25° C., where the ratio of cannabis plant material and solvent is such that all cannabis plant material is submerged in the solvent completely in the reaction vessel.
Upon the completion of sonication of the mixture of cannabis plant material and solvent, the solvent is removed from the mixture. Removal of the solvent can occur by any means known in the art, including but not limited to filtration and/or evaporation. One embodiment for filtering after sonication is vacuum filtering over a glass sintered funnel to separate the resultant extract in the filtrate and the plant material. The latter can then be subjected to further extractions such as Soxhlet or other solvent extractions as is known to those skilled in the art, for example, SFE.
In yet another embodiment of extraction step 106, cannabinoids can be extracted from cannabis plant material that is broken down in step 104 by reflux (Soxhlet) extraction.
During reflux (Soxhlet) extraction, cannabis plant material that is broken down in step 104 is generally suspended above a heated solvent in a receptacle. The solvent is heated to reflux in a distillation flask such that solvent vapor travels up a distillation arm and floods into the receptacle housing raw cannabis material. A condenser suspended above the raw cannabis material ensures that any solvent vapor rising above the raw cannabis material cools and subsequently drips back down into the receptacle housing the raw cannabis material. The receptacle slowly fills with warm solvent such that cannabinoids begin to dissolve into the warm solvent. When the receptacle fills, it is emptied by a siphon such that the solvent is returned to the distillation flask. This cycle may be allowed to repeat many times, over hours or days.
Preferably, reflux (Soxhlet) extraction occurs at a solvent temperature higher than the boiling point of the corresponding solvent used for extraction and is conducted over a period of approximately 3 to 5 hours.
Once extraction is complete, removal of the solvent can occur by any means known in the art, including but not limited to filtering and/or evaporation as previously described.
In place of either sonication or reflux (Soxhlet) extraction as described above, another embodiment of extraction step 106 encompassed by the subject application is the extraction of cannabinoids from cannabis plant material by SFE.
SFE refers to a process of separating one or more components (extractant) from another (matrix) using supercritical fluids as the extracting solvent. Extraction is usually from a solid matrix (e.g. cannabis plant material), but can also be from liquids or resinous material (for example, hash oil).
Although numerous supercritical fluids can be used, carbon dioxide (CO2) is the most commonly used supercritical fluid for SFE. In other exemplary embodiments, CO2 can be modified by co-solvents such as ethanol or methanol as is known to those skilled in the art.
Extraction conditions for supercritical fluids are above the critical temperature (for example, 31° C. for CO2) and critical pressure (for example, 74 bar for CO2). Addition of modifiers such as but not limited to ethanol can require altering these extraction conditions.
An exemplary SFE system contains a pump for CO2 (as well as any other solvents), a pressure cell to contain the cannabis material, a means of maintaining pressure in the system and a collecting vessel. The liquid is pumped to a heating zone, where it is heated to supercritical conditions. It then passes into the extraction vessel, where it rapidly diffuses into the solid matrix and dissolves the cannabis material to be extracted. The dissolved material (for example, cannabinoids) is swept from the extraction cell into a separator at lower pressure, and the extracted material settles out. The CO2 can then be cooled, re-compressed and recycled, or discharged to atmosphere.
Herein, the temperature of the SFE extraction performed at extraction step 106 can, in some embodiments, be in the range of 35-55° C.
Further the pressure the SFE extraction performed at extraction step 106 can in some embodiments be in the range of 65-85 bar.
SFE in the present disclosure occurs at about 40° C. with a back pressure regulator pressure of 12 MPa and the extracted compounds are monitored using a photodiode array of 200-600 nm (monitoring at 254 nm). The acquisition time and method times of the system can each vary by a few minutes up to 60 minutes, ideally between 15 and 30 minutes, depending on the ratio of supercritical fluid and the co-solvent is altered for the extraction.
In specific embodiments, SFE can be carried out multiple times in succession. In such embodiments, the SFE is a fractional SFE.
As previously described for sonication with a solvent and reflux (Soxhlet) extraction, once SFE is complete, removal of the solvent can occur by any means known in the art, including but not limited to filtering and/or evaporation.
Microwave-assisted Extraction and Decarboxylation 108
Decarboxylation of phytocannabinoid acids such as Δ9-THC-A is a function of the time and temperature of the reaction. For instance, the decarboxylation of concentrated Δ9-THC-A in solution into Δ9-THC and the degradation of Δ9-THC vary with temperature. Temperature controls are therefore important for controlling desired ratios of decarboxylation products. The use of conventional household microwaves in the processing of cannabis has been discussed in the literature, however, with mixed, inconsistent results and not necessarily specifically for extraction in a solvent and decarboxylation. Further, in order to obtain 100% decarboxylation, the temperature must be sustained over a period of time without burning of the cannabis material or boiling/evaporation of the solvent. If the temperature is higher than the boiling point of the solvent employed, the solvent will boil over and/or evaporate. In order to sustain the temperature over the required period of time to fully decarboxylate the cannabinoids but not burn the cannabis plant material or boil/evaporate the solvent with the cannabis, the microwave vessel (i.e. the sealed container) must be under pressure. Sealing the vessel or container ensures pressure in the vessel or container.
As shown in
Microwave assisted extraction and decarboxylation 108 can comprise suspending cannabis plant material in a solvent and subjecting the mixture to microwaves in a closed container at a temperature, pressure and time sufficient to form decarboxylated cannabinoids.
Herein, the term “microwaves” refer to a form of electromagnetic radiation with wavelengths ranging from one meter to one millimeter; with frequencies between 300 MHz (100 cm) and 300 GHz (0.1 cm).
Further, solvent treatment in microwave assisted extraction and decarboxylation step 108 is again to remove non-cannabinoid impurities to leave a substantially pure preparation of cannabinoids. As such, non-polar, liquid solvents are useful for this function. In one embodiment, ethanol is used as the liquid solvent in microwave assisted extraction and decarboxylation step 108. In another embodiment, 95% ethanol is used as the liquid solvent in microwave assisted extraction and decarboxylation step 108.
As ethanol has a boiling point of 78° C. and the decarboxylation process of cannabis is temperature dependent (as described above), temperature control is important in microwave-assisted extraction step 108.
In one exemplary embodiment, suitable conditions to promote decarboxylation of CBDA and THCA to CBD and THC, respectively, are to suspend the cannabis plant material in a solvent (such as ethanol) and then subject this mixture to electromagnetic radiation (for example, microwaves) of a wavelength in the range of 106-109 nm and a frequency of 300 MHz-300 GHz. In one embodiment, the conditions further include, for example, the following: temperature range of 40-250° C., temperature increase of 2-5° C./sec, pressure range of 0-20 bar (2 MPa, 290 psi), microwave power range of 0-400 W at 2.45 GHz or minor variations and adjustments to suit a particular solvent and/or reaction conditions to reach the required temperature and accomplish decarboxylation. If stirring is required, a variable magnetic stirrer (300-900 RPM) may be used.
In another exemplary embodiment, microwave assisted extraction and decarboxylation can be performed at a temperature in the range of 100-200° C. (including all possible integers and fractions of integers in this range, for example, 163.5° C.), 130-170° C., 150-170° C. or 130-150° C.
In another exemplary embodiment, microwave assisted extraction and decarboxylation can be performed at a pressure in the range of 2-22 bar (including all possible integers and fractions of integers in this range), for example, 10.7 bar or 17 bar or 18 bar or 19 bar or 20 bar or 21 bar.
The cannabis plant material can be suspended in a solvent and subjected to microwaves at frequency and wavelength of 2.45 GHz and 1.22×108 nm, respectively, and a temperature in the range of 130-190° C.
The raw cannabis material can be suspended in a solvent and subjected to microwaves at frequency and wavelength of 2.45 GHz and 1.22×108 nm, respectively, and a temperature in the range of 150-190° C. and the solvent is ethanol.
In another embodiment, cannabis plant material can be suspended in a solvent and the mixture stirred for a defined period of time (e.g. 0-30 sec or a reasonable length of time so as to suspend the material) before being subjected to microwaves. In one embodiment, the defined period is 30 seconds.
In another embodiment, cannabis material can be suspended in a solvent and the mixture can be stirred while being subjected to microwaves. In one embodiment, the defined period is 10 minutes and in another embodiment the defined period is 20 minutes. A table of working microwave variables is provided below for reference.
The parameters below can be set by the user, depending on the type of microwave equipment employed and the options available for user settings:
The parameters below were observed and extrapolated.
In some embodiments, the decarboxylated cannabinoid product can be used directly or further processed, purified or recovered prior to use.
Recovery 110
Optionally, after being subjected to microwaves, a preparation of decarboxylated cannabinoids can be recovered from the resulting suspension at recovery step 110.
In one embodiment, extracted and decarboxylated cannabinoids are recovered by filtering the solvent from the extract of cannabis plant material to isolate the decarboxylated cannabinoids or decarboxylated cannabinoid comprising fraction.
In another embodiment, extracted and decarboxylated cannabinoids are recovered by filtering through an appropriate Celite® pad and/or activated carbon (e.g. charcoal) to obtain clarified solution for subsequent processing or use. In this embodiment, Celite® can be placed in a glass sintered funnel and then layered with activated carbon. Filtering agents can be washed with ethanol via vacuum filtration and extract can be dissolved in appropriate volume of suitable solvent such as ethanol and transferred to a funnel. Vacuum can then be applied and the filtering agent can be washed with the solvent until cannabinoids are completely eluted. The resulting filtrate can then be concentrated to dryness (e.g. at 25° C.). Someone with skill in the art can also conceive employing functionalized membranes, cellulose filters or the like to accomplish the above recovery task, instead of Celite® and activated carbon pad.
Alternatively, the resulting preparation of decarboxylated cannabinoids from step 108 can be collected and subsequently processed according to any of the extraction methods described in step 106, including but not limited to sonication, reflux (Soxhlet) extraction and/or SFE.
Uses and Products
The decarboxylated cannabis resins can be used (i) directly as a medicine, natural health product, or for recreational use, or (ii) as a raw material in the preparation of products, such as pharmaceutical, natural health products, or recreational use products for known uses of decarboxylated cannabinoid(s), such as known therapeutic or psychoactive uses.
In one embodiment, the decarboxylated resin of the disclosure can be used directly, for example as a medicine or as a natural health product.
In one embodiment, a pharmaceutical composition can be formed comprising the resulting decarboxylated cannabinoid resin produced by the methods disclosed, which can further comprise a suitable pharmaceutical acceptable carrier or excipient.
The pharmaceutical compositions of the present disclosure can additionally comprise one or more further active pharmaceutical ingredients in addition to decarboxylated cannabinoids.
Pharmaceutical compositions can be prepared in various dosage forms depending on the desired use and mode of administration, whether it is oral (e.g., tablet or liquid forms), a mist or other forms (aerosol, inhaler or intravenous suitable formulations), as desired, using techniques well known in the art.
Pharmaceutically acceptable carriers or excipients for various different dosage forms are well-known in the art and include carriers, diluents, fillers, binders, lubricants, disintegrants, glidants, colorants, pigments, taste masking agents, sweeteners, flavorants, plasticizers, and any acceptable auxiliary substances such as absorption enhancers, penetration enhancers, surfactants, co-surfactants, and specialized oils. The proper excipient(s) is (are) selected based in part on the dosage form, the intended mode of administration, the intended release rate, and manufacturing reliability. Examples of common types of excipients include various polymers, waxes, calcium phosphates, and sugars.
A person of skill in the art would reference known methods of pharmaceutical preparations, such as described in Remington: The Science and Practice of Pharmacy, 22nd Edition, Edited by Allen, Loyd V., Jr, 2012.
The present disclosure is described in the following Examples, which are set forth to aid in the understanding of the disclosure, and should not be construed to limit in any way the scope of the disclosure as defined in the claims which follow thereafter.
Decarboxylated Cannabis Resin
Medicinal cannabis was subjected to extraction and chemical analysis by UPLC-MS.
Extraction Methodologies
UPLC-MS Methodology. Cannabinoid standards, cannabis extracts and cannabinoids in the donor samples were analyzed using Waters® ACQUITY UPLC H-Class System equipped with Quaternary Solvent Manager and Sample Manager FTN. The detector used to monitor the samples was Waters® MS 3100 mass spectrometer. Benzophenone, caffeine or Δ9-THC-d3 was used as an internal standard. Conditions are listed in Table 2.
Extraction Results.
Chemical Analyses by UPLC-MS.
Mass spectra of Strain 1 before (
Closed system microwave extraction provides simultaneously extraction and decarboxylation of the cannabinoids, as observed during chemical analysis by UPLC-MS.
Method 1A: Ultrasonic Extraction (Sonication).
General Procedure:
Table 5 below shows the results of sonication of three common strains of cannabis.
Method 1B: Filtration over Celite®/Activated Carbon.
Following Method 1A (described above), extracts were subjected to filtration over Celite® and activated carbon in order to eliminate the green colour of extracts. The results are shown in Table 6.
General Procedure:
Method 2: Soxhlet Extraction
General Procedure:
Table 7 below provides the results of Soxhlet extraction of cannabis according to the forgoing procedure.
Method 3: Supercritical Fluid Extraction (SFE)
General Procedure:
Method 3A: SFE Conditions
Method 3B: SFE Conditions
Table 8 below shows the results of SFE according to the conditions outlined in Methods 3A and 3B for cannabis.
Method 4: Microwave-Assisted Extractions with Ethanol (MAE) Followed by SFE.
Suitable conditions to promote decarboxylation of CBDA and THCA to CBD and THC, respectively, were determined with MAE.
The solvent used for this extraction was ethanol. However, since ethanol has a boiling point of 78° C., the highest temperature that could be achieved when heating only ethanol in a sealed vessel under microwave conditions had to be determined.
General Procedure:
The results are shown in Table 9 below.
Once the maximum temperature that ethanol could be heated was determined, the following conditions were performed with cannabis:
General Procedure:
The results are shown in Table 10 below.
Table 14 (provided below) shows the analyses and quantification of the cannabinoids.
Method 5. SFE/Soxhlet/Sonication Extraction Followed by Microwave of the Resin (for Decarboxylation).
General Procedure:
The results are shown in Table 11 below.
Chromatography Analyses (HPLC/MS/PDA)
The chromatographic profiles of the cannabis extracts were determined by LC-PDA-MS equipped with a Waters® 2545 binary gradient module LC, Waters® PDA2998 photodiode array detector (190-800 nm) and a Waters® 3100 mass spectrometer (60-2000 Da).
LC was performed on an X-Bridge analytical C18 column (4.6 mm×150 mm, 5 um I.D.) with 1.5 mL/min flow rate. Mass spectra were recorded using ESI (+ve) mode. The injection samples were filtered using Millex-GV® Syringe Filters (0.22 μm, EMD Millopore).
Chromatographic conditions were as follows:
UPLC/MS. The cannabis extracts and cannabinoid standards were analyzed using Waters® ACQUITY UPLC H-Class System equipped with Quaternary Solvent Manager, Sample Manager FTN, Acquity UPLC® BEH column (2.1×50 mm, C18, 1.7 μm). The sample injection plate and the column were maintained at 15° C. and 40° C., respectively. The detector used to monitor the samples was Waters® MS 3100 mass spectrometer.
Chromatographic conditions were as follows:
Standard Curves for Cannabinoids:
Standard cannabinoids samples were purchased from Cerilliant-Certified Reference Standards in the form of 1.0 mg/mL solution in methanol.
The chemical structures of cannabinoids 1-6 are provided in
Working stock solution of each standard sample was prepared using water/0.1% formic acid and methanol/0.1% formic acid. The final concentration of each stock sample was 50 μg/mL in 30% water/0.1% formic acid and 70% methanol/0.1% formic acid.
The stock samples (50 μg/mL) were diluted with mobile phase (30% water/0.1% formic acid and 70% methanol/0.1% formic acid) to obtain the following concentrations:
Not all the concentrations were included in the construction of the standard curve. Some of the cannabinoids (e.g. 0.1 or 10.0 μg/mL) were excluded due to very low signal of saturation level.
Each concentration was run in triplicate. 2 μL injections were made and the signal was recorded for up to 6 minutes. SIR+ve (311, 315, and 359 m/z) or SIR −ve (313 and 357) and mass scan (150-500 m/z) in positive mode were monitored and recorded. SIR chromatograms were integrated and the AUC was plotted vs. concentration (μg/mL).
Standard curves for each of cannabinoids 1-6 as described above are provided in
Table 13 provides the concentration (μg/mL) of cannabinoids in extracts obtained using microwave extraction method at different temperatures. The solid material (plant fiber) leftover after the microwave reaction was exposed to SFE extraction (method 3A). The total volume of each microwave reaction was 3 mL.
Table 14 shows the amount of cannabinoids in the cannabis extracts, after subjecting to Method 5. See also Table 11. Note: CBN appears to be formed during the microwave based decarboxylation of THCA. CBDA was not quantified.
A plot of the above data is shown in
Table 15 shows the yield (mg/g of plant material) of cannabinoids in the extracts obtained using microwave extraction method at different temperatures. The solid material (plant fiber) left over after the microwave reaction was exposed to SFE extraction (method 3A). The total volume of each microwave reaction was 3 mL. CBDA was not quantified.
Summary of Results for Experiment 2
Table 5 shows the use of various solvents during ultrasonic extraction. There were also minimal amounts of cannabis plant material lost during the recovery filtration process (see Table 6). This also appears to be similar recovery across different extraction methods—solvent, Soxhlet, SFE extraction (See Tables 7 and 8).
When conducting cannabinoid extraction/decarboxylation in ethanol using a microwave, due to the boiling point of ethanol, it was shown that extraction/decarboxylation of cannabinoids using a microwave is best conducted at temperatures below 180° C., for example at 160° C.±10° C. (e.g. +/−the acceptable standard of error). It was also shown under the conditions used that conversion of THCA to THC (the desired decarboxylated product) was better at 130° C. than at 100° C., and that if conducted using microwave alone versus microwave and SFE, temperatures above 130° C., for example from 150° C. to 170° C. showed more efficient conversion. (See Tables 13 and 15 as well as
From the above results, it appears that the significant decarboxylated product THC results from microwave extraction and that the addition of a second extraction step, such as SFE, does not appear to change the cannabinoid profile. It further shows that CBD as well as THC components are present in extract after microwave extraction alone or with microwave and SFE extractions combined.
In summary, the present disclosure shows that extraction and decarboxylation of cannabis plant material can be done concurrently using a microwave, set at a temperature below the boiling point of the extraction solvent, such as ethanol, without the need for a separate extraction step. This optimizes decarboxylated cannabinoid formation and recovery and can produce a more consistent and reproducible product with consistent and reproducible efficacy and therapeutic results.
An extraction step can also be included before use of a microwave. Although an extraction step after the microwave step is possible, it is not necessary.
General Procedure:
A) SFE conditions
Table 16 below shows the corresponding results.
General Procedure:
The results are shown in Table 17 below.
General Procedure:
The results are shown in Table 18 below.
aDesired temperature could not be achieved due to pressure build-up; cap of vial popped off causing solvent and plant fibre to escape from vial.
Since condition (b) in step 3 above proved successful at that scale, subsequent decarboxylations were performed using that microwave condition and were done in triplicate. However, the following modifications were made:
Step 1: Blend at 18,000 rpm for 4 secs
Step 4: Filtration done over celite/activated carbon (as previously described in an earlier report)
Step 5: Filtrate was then concentrated at 35° C., weighed, transferred to a 20 mL vial using ethanol, then stored in the refrigerator
The results are shown in Table 19 below.
This experiments shows the consistency of the extraction method.
General Procedure (˜1.0 g Batch; Before Maceration):
Winterization Procedure:
aAverage calculations based on runs 2 and 3 only.
Summary of results: Extracting and decarboxylating 1 gram scale batch of cannabis was successful.
The results are shown in Table 22 below.
bPlant fibre is supplied as pulverized buds. Size was appropriate, therefore no further maceration was done.
cDesired temperature of 150° C. could not be achieved due to pressure build-up.
(A) General Procedure (˜3.75 g Batch; Before Maceration):
Winterization Procedure:
b
aNo winterization was performed on run 1; winterization done on run 2 only.
b Plant fibre is supplied as pulverized buds. Size was appropriate, therefore no further maceration was done.
aCalculations based on run 2 only.
(B) General Procedure (˜7.5 q Batch; Before Maceration):
Winterization Procedure:
(C) General Procedure (˜4.0 and 7.0 g Batches; Before Maceration):
Winterization Procedure:
Summary of results: Extracting and decarboxylating 3.75 gram scale batch of cannabis was successful.
The results are shown in Table 29 below.
Winterization is a procedure typically used to remove waxes and other partially soluble materials at 0±10° C. temperature range. This process may not be applicable, if there are no waxes present in the extract, or such hydrophobic molecules are broken down, and would be solidify at the ice-bath or below-zero temperatures.
Experiment 10A
To remove waxes, the solutions of extract which had been stored in the refrigerator (−5° C.) for 1-3 weeks were manipulated as follows:
Experiment 10B
The results are shown in Tables 30a and b below.
Summary of results: Winterization of extracts was successful in removing waxes from the extract.
Methodology
Extraction: Dried plant material (1 g) was weighed and transferred to a mortar and was macerated using a pestle. The crused plant material was then transferred into a 10 mL vessel and was subjected to supercritical fluid extraction (SFE), with supercritical CO2 as solvent A and ethanol as solvent B. The photodiode array detector was set to monitor wavelengths in the range of 200-600 nm and the back pressure regulator was set to 12 MPa. The SFE conditions used were: flow rate=10 mL/min (CO2 and slave pumps) and 1 mL/min (make-up pump); temperature=25° C.; gradient: 100% A−50% A (0.1-25 mins), 100% B (25-26 mins) and 100% A (26-30 mins). Once the method was completed, all fractions were combined and concentrated to dryness under reduced pressure (at 25° C.) to afford 0.28 g of a green sticky resin. This was used for further work-up and analyses.
Activation: Activation of phytocannabinoids was conducted by subjecting cannabis extract to heat using microwaves. A 5 mL-size microwave vial was charged with cannabis extract (27.72 mg) dissolved in ethanol (2 mL). The vial was sealed and was subjected to heat for 10 min at 150° C. in a pressure vessel to afford a green sticky extract. This was concentrated to dryness at 35° C. to obtain the activated cannabis extract as a resin (21.2 mg).
Table 32. Potential changes in chemical composition after decarboxylation of strain I cannabis extract. Left column indicates the potential compounds that were present in cannabis extract obtained through a supercritical fluid extraction (SFE), but not in the decarboxylated resin. This extract was then subjected to heating conditions using microwave technology, and the right column shows the new chemicals that were identified, which were not present in the cannabis extract prior to employing microwave technology described in this disclosure.
Closed system, microwave extraction provided the simultaneous extraction and decarboxylation of the cannabinoids. In the native cannabis extract, 63 compounds could be observed (
General Procedure
To remove the solvent from the decarboxylated resin, the following procedures are used:
distillers or rotary evaporators are used to evaporate solvents employed in extraction and decarboxylation process, concentrate and obtain solvent-free decarboxylated resin. During the evaporation of solvent, a higher temperature than ambient temperature is used to facilitate faster evaporation of the solvent. In addition, a vacuum may be used to facilitate removal of solvent at lower pressure than the atmospheric pressure. In general, such processes are well established and known to those skilled in the art.
The resulting decarboxylated cannabis resin may comprise less than 5% solvent, or the resin can be solvent-free.
Where aspects or embodiments of the invention are described in terms of a Markush group or other grouping of alternatives, the present invention encompasses not only the entire group listed as a whole, but each member of the group individually and all possible subgroups of the main group, but also the main group absent one or more of the group members. The present invention also envisages the explicit exclusion of one or more of any of the group members in the claimed invention.
Numerical data may be presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of about 1 to about 4.5 should be interpreted to include not only the explicitly recited limits of 1 to about 4.5, but also to include individual numerals such as 2, 3, 4, and sub-ranges such as 1 to 3, 2 to 4 etc. The same principle applies to ranges reciting only one numerical value, such as “less than about 4.5,” which should be interpreted to include all of the above-recited values and ranges. Further, such an interpretation should apply regardless of the breadth of the range or the characteristic being described.
While the foregoing disclosure has been described in some detail for purposes of clarity and understanding, it will be appreciated by one skilled in the art, from a reading of the disclosure that various changes in form and detail can be made without departing from the true scope of the disclosure in the appended claims.
All publications, patents, and patent applications are herein incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.
This application is a continuation filing of U.S. patent application Ser. No. 15/637,043, filed on Jun. 29, 2017, which issued as U.S. Pat. No. 10,143,706 on Dec. 4, 2018, which itself claims priority under the Paris Convention to U.S. Provisional Patent Application Ser. No. 62/356,262, filed Jun. 29, 2016, each of which is incorporated herein by reference as if set forth in its entirety.
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| Number | Date | Country | |
|---|---|---|---|
| 20190038663 A1 | Feb 2019 | US |
| Number | Date | Country | |
|---|---|---|---|
| 62356262 | Jun 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15637043 | Jun 2017 | US |
| Child | 16157687 | US |
