FIELD OF THE INVENTION

The present invention relates in general to methodology for the extraction of products from cannabis.

BACKGROUND OF THE INVENTION

Cannabis is a well-known plant genus, including the species cannabis sativa, cannabis indica and cannabis ruderalis, that has for many years been used industrially for its fibre and seed oil (derived from varieties known colloquially as hemp) or smoked as a recreational drug.

Despite its rather basic application in society to date, cannabis is a complex plant genus whose species can contain over 500 compounds, including at least 70 cannabinoid compounds such as tetrahydrocannabinolic acid (THCA) and cannabidiolic acid (CBDA), being precursors to the more widely known tetrahydrocannabinol (THC) and cannabidiol acid (CBD), respectively.

The application diversity of cannabis derived products is only now being realised, with cannabis derived medicinal products entering mainstream commercialisation. Use of cannabis and cannabis derived products as a recreation drug is also becoming legalised in many countries.

On the back of such commercial interest, considerable research and development is being performed to better understand the range of compounds produced by cannabis, the medical application of such compounds and also to identify new applications for cannabis extracts and extracted cannabis.

An important part of such research and development is methodology for extracting products from the cannabis. Conventional cannabis extraction techniques typically involve first drying the harvested cannabis and then exposing the dried cannabis to solvent into which a product is extracted.

The cannabis is typically dried prior to solvent extraction to avoid water present in the freshly harvested cannabis contaminating/dele die looting ting the extraction solvents. For example, the extraction solvents are typically recycled/reused and having to remove water from those solvents adds complexity and cost to the overall process.

The harvested cannabis may be dried using a variety of techniques, including air drying or so-called hang-drying, oven drying and freeze-drying. Freshly harvested cannabis typically has a water content of about 80 weight %. Drying is performed to reduce the water content of the cannabis typically down to a range of about 5 - 15 weight %.

Although considered an important step in a solvent extraction process, drying of cannabis is time-consuming and labour-intensive. Some drying techniques are also prone to the cannabis becoming undesirably contaminated with mould/fungi.

Common solvents used for extracting products from cannabis include ethanol, carbon dioxide, and hydrocarbons such as propane, butane and hexane.

While conventional solvent extraction techniques are generally effective at extracting desired products from cannabis, they are nevertheless prone to extracting products that contain a vast array of compounds, many of which are non-target compounds and possibly undesirable.

Conventional solvent extraction techniques therefore typically afford a broad spectrum product that is often required to undergo further substantive processing to yield a more targeted, refined or isolate product.

Techniques have been developed that afford improved extraction selectivity, for example techniques such as supercritical fluid extraction. However, those techniques require complex and expensive equipment and are not well suited to industrial scale up. While steam extraction of products from some plant species is efficient/effective, that technique is not typically applied to cannabis. Cannabis extraction typically focusses on the extraction of cannabinoids from dried cannabis. Steam extraction is ineffective at extracting cannabinoids from cannabis. With the inability to efficiently extract cannabinoids from cannabis using steam extraction, the introduction of water via the steam extraction process will typically be considered problematic for subsequent solvent extraction steps.

An opportunity therefore remains to develop new methodology for extracting products from cannabis that address or ameliorate one or more shortcomings associated with conventional methodology, or at the very least provides for a useful alternative.

SUMMARY OF THE INVENTION

The present invention provides a method for selectively extracting two or more different products from cannabis, the method comprising:

(i) providing steam cannabis and a first extraction solvent system in a container, the first extraction solvent system comprising a mixture of two or more miscible solvents that has a first dielectric constant;

(ii) maintaining the steam cannabis in contact with the first extraction solvent system so as to promote extraction of a first product from the cannabis into the first extraction solvent system and produce solvent extracted cannabis;

(iii) separating the first extraction solvent system comprising the first product from the solvent extracted cannabis;

(iv) introducing into a container with the solvent extracted cannabis separated from step (iii) a second extraction solvent system comprising a mixture of two or more miscible solvents having a different dielectric constant to that of the first extraction solvent system used in step (i); and

(v) maintaining the solvent extracted cannabis in contact with the second extraction solvent system so as to promote extraction of a second product from the solvent extracted cannabis into the second extraction solvent system, wherein the second product has a different composition to the first product. In one embodiment, prior to undertaking step (i) the method further comprises introducing steam into a container comprising source cannabis where the steam (a) extracts from the source cannabis a steam extracted product comprising terpenes and has a different composition to the extraction solvent system extracted products produced in subsequent steps, and (b) affords steam extracted cannabis, wherein the so formed steam extracted cannabis is used as the source of steam extracted cannabis in step (i).

In one embodiment, the steam extracted cannabis is retained in the container and used as the source of cannabis in step (i).

It has now been found products can be efficiently and selectively extracted from cannabis using simple and cost effective methodology that involves applying multiple extractions to the same source of cannabis using (i) steam extracted cannabis and (ii) extraction solvent systems (a) having different dielectric constants, and (b) that are derived from two or more miscible solvents. The use of the steam extracted cannabis in combination with the extraction solvent systems derived from two or more miscible solvents (that enables a diverse range of dielectric constants to be accessed) advantageously enhances product extraction efficiency and selectivity.

Notably, product extraction selectivity provided by the method of the invention can be achieved without the need for complex and expensive equipment as the method of the invention is not performed using supercritical fluid extraction. Furthermore, the method of the invention can advantageously be performed at lab scale through to industrial scale.

The use of steam extraction to provide for a source of steam extracted cannabis advantageously removes terpenes from the source cannabis product without adversely affecting the cannabinoid content of the cannabis. The isolated terpene product can be retained for subsequent blending into cannabis products if desired. It has been found the resulting steam extracted cannabis (now deficient of terpenes) can be subjected to the solvent extraction steps of the method to enable highly efficient and selective extraction of cannabis derived compounds, such as cannabinoids. Those extracted compounds typically require less or no subsequent purification and can therefore be used commercially in their own right or blended with one or more other products to produce tailored cannabis extract products.

The application of a steam extraction step/steam extracted cannabis in accordance with the invention advantageously also enables the source cannabis that is to be used to be freshly harvested cannabis (i.e. not dried cannabis), which in turn provides access to terpene rich fresh flowers to provide higher yield terpene extracts (i.e. dried cannabis loses a significant portion of the highly volatile terpene compounds). The use freshly harvested cannabis having a high water content advantageously does not present any adverse processing concerns using steam extraction.

The steam extraction process used to produce the steam extracted cannabis also advantageously facilitates conversion (i.e. decarboxylation) of THCA and CBDA into THC and CBD, respectively.

The steam extraction process may also extract flavonoids from the source cannabis, which again can be retained for subsequent use if desired. The removal of such flavonoids from the cannabis is also believed to enhance the efficiency and selectivity of the subsequent solvent extraction steps.

The combination of using steam extracted cannabis and its subsequent solvent extraction in accordance with the present invention surprisingly has been found to improve extraction efficiency and selectivity. For example higher yields of more pure cannabinoids can be extracted from the cannabis. Without wishing to be limited by theory, it is believed that the initial steam extraction of the source cannabis at least (i) selectively removes a variety of compounds, including terpenes, that are typically difficult to separate when present in mixture with cannabinoids, (ii) damages/fractures the cannabinoid rich trichome cell structure of the cannabis, and (iii) decarboxylates at least the cannabinoids THCA and CBDA into THC and CBD, respectively. Those combined features advantageously are believed to enable the solvent extraction steps in accordance with the invention to extract higher yield of more pure cannabinoids from the steam extracted cannabis. In particular, the removal of steam and extractables from the cannabis reduces contamination in the subsequent cannabinoid extractions, the damaged/fractured trichome cells of the cannabis become more prone to releasing higher levels of cannabinoids, and the decarboxylated cannabinoids are more soluble in the solvent extraction media used.

Extracted cannabis that is (a) formed in accordance with the invention, and (b) to be subjected to a subsequent extraction step may be (i) retained in the same container in which it was previously extracted for undergoing the subsequent extraction step, or (ii) removed from the same container in which it was previously extracted and placed in a separate container for undergoing the subsequent extraction step.

In one embodiment, the same container is used for each extraction step and the extracted cannabis is not removed from the container between extraction steps.

In another embodiment, the extracted cannabis is removed from its extraction container after at least one extraction step and placed in a different container for a subsequent extraction step.

For avoidance of any doubt, the extraction systems used in accordance with the invention are not supercritical fluids.

Also for avoidance of doubt, reference to "steam extracted cannabis" used herein is intended to mean source cannabis that has been subjected to steam extraction. Generally, the source cannabis will be either dried, partially dried or fresh cannabis that has not previously be subjected to any form of extraction.

The method of the invention can advantageously be performed using cannabis having any water content (i.e. freshly harvested or dried cannabis).

Other advantages afforded by the invention offset any disadvantages associated with possible water contamination in solvent systems used in accordance with the method.

According to the method of the invention, steam cannabis is exposed to a first extraction solvent system comprising two or more miscible solvents having a first dielectric constant so as to extract a first product. The dielectric constant of the first extraction solvent system will typically be tailored to selectively extract the first product having a desired composition. In a subsequent step, the composition of the first extraction solvent system is adjusted to afford a second extraction solvent system having a different dielectric constant that is used to extract a second product from the previously extracted source of cannabis. The dielectric constant of the second extraction solvent system will be tailored to selectively extract the second product having a desired composition that is different to the first product. Notably, the second product is extracted from the source of cannabis from which the previous first product had been extracted.

The different dielectric constants of the first, second, etc, extraction solvent systems can be promoted simply by changing the composition of the respective extraction solvent systems. For example, that may involve using a combination of different two or more miscible solvents or using a combination of the same two or more miscible solvents, but at different ratios.

The method can advantageously be extended to employ one or more further similar extractions to produce additional unique products using at each extraction step two or more miscible solvents having a different dielectric constant to that used previously.

For example, in one embodiment the method further comprises:

(vi) separating the second extraction solvent system comprising the second product from the solvent extracted cannabis;

(vii) introducing into a container with the solvent extracted cannabis separated from step (vi) a third extraction solvent system comprising a mixture of two or more miscible solvents that has a different dielectric constant to that of the first extraction solvent system used in step (i) and the second extraction solvent system used in step (iv); and

(viii) maintaining the solvent extracted cannabis in contact with the third extraction solvent system so as to promote extraction of a third product from the solvent extracted cannabis into the third extraction solvent system, wherein the third product has a different composition to the first and second product. For avoidance of any doubt, the reference to first, second, third etc extraction solvent systems and products used in or derived from the method of the invention is not intended to define limiting sequential numerical occurrences, but rather occurrences that occur in merely a subsequent step (i.e. not necessarily in the next step). For example, the first extraction solvent system might be used in two sequential extraction steps, which is then followed by using the second extraction solvent system. In that case, the second extraction solvent system is used in the overall third extraction step.

Accordingly, if desired a given extraction solvent system (e.g. a first, second, third etc extraction solvent system) can be used multiple times. For example, the method may involve using sequentially a first, first, second, second, third, and fourth extraction solvent system.

In other words, provided the method makes use of at least a first and a second extraction solvent system as herein described, the use of those extraction solvent systems does not have to correspond to the actual first and second extractions per se undertaken.

For convenience, the expression "dielectric constant" may herein be abbreviated as "Dk".

As a more specific example only, the cannabis may be sequentially extracted as described using (i) a first extraction solvent system made up of 10% ethanol and 90% water having a Dk "A" to afford a first product, (ii) a second extraction solvent system made up of 50% ethanol and 50% water having a Dk "B" to afford a second product, (iii) a third extraction solvent system made up of 70% ethanol and 30% water having a Dk "C" to afford third product, and (iv) a fourth extraction solvent system made up of 90% ethanol and 10% water having a Dk "D" to afford a fourth product (where A, B, C and D represent different dielectric constants).

In such an example, sequentially adjusting the ratio of the ethanol/water affords extraction solvent systems having different dielectric constants that advantageously enables a much higher degree of product extraction selectivity compared with conventional solvent extraction methods. In particular, the dielectric constant of each extraction solvent system can be readily tailored at each extraction step to target extraction of a desired product. Such extraction selectivity advantageously enables products derived from the method to require reduced downstream processing and/or the production of new products.

For example, the method according to the invention can advantageously be applied so as to selectively extract direct from the steam extracted cannabis a specific cannabinoid product or profile. That method might first involve one or more extractions designed to extract one or more non-target products (e.g. terpenes, flavonoids and sugars), followed by an extraction designed to selectively extract the target cannabinoid product while not extracting other nontarget products (e.g. chlorophyll and waxes). The target cannabinoid product can advantageously be extracted efficiently to provide a relatively high concentration product that does not include non-target extract products and thereby warrants minimal downstream processing.

As a further example, the method according to the invention can advantageously be applied so as to selectively extract direct from the cannabis two or more non-target extract products (e.g. terpenes, flavonoids and sugars) whilst retaining within the extracted cannabis one or more target products (e.g. THC and CBD). The resulting commercial product of that method may be the extracted cannabis itself that has reduced levels, or is devoid, of at least some non-target products, but still contains one or more target products.

Commercially viable products produced in accordance with the method of invention therefore include those extracted from the cannabis, but also the extracted cannabis itself.

The composition of products extracted from the cannabis in accordance with the invention can advantageously be adjusted/tailored by correspondingly adjusting/tailoring the dielectric constant of an extraction solvent system. In that way, the resulting extract products produced directly from the method can be highly selective and compound specific, thereby minimising downstream processing/purification.

Further aspects and embodiments of the invention are discussed in more detail below. BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the invention will now be described with reference to the following nonlimiting drawings in which:

Figure 1 illustrates a schematic of equipment that may be used to perform the present invention;

Figure 2 illustrates a schematic of equipment that may be used to perform the present invention;

Figure 3 illustrates a schematic of equipment that may be used to perform the present invention;

Figure 4 illustrates a schematic of equipment that may be used to perform the present invention;

Figure 5 shows a picture of extraction products from Example 1; and

Figure 6 shows a picture of extraction products from Example 2.

DETAILED DESCRIPTION OF THE INVENTION

Reference herein to cannabis is intended to mean members of the genus including the species cannabis sativa, cannabis indica and cannabis ruderalis. The cannabis plant genus also includes so-called hemp varieties.

A “product” or “products” extracted from cannabis as described herein is intended to mean a compound or a mixture of different compounds. In accordance with the method of the invention an extracted product produced in one extraction step has a different composition to an extracted product produced in a previous or subsequent different extraction step. For example, the first extraction product produced using the first extraction solvent system has a different composition to the second extraction product produced using the second extraction solvent system. By having a “different composition” is intended to mean a given extracted product contains one or more different compounds compared to those contained in another extracted product, and/or where a given extracted product contains a different ratio of one or more compounds compared to those contained in another extracted product. Product produced in accordance with the invention includes not only one or more compounds extracted from cannabis, but also the extracted cannabis itself. Extracted cannabis is intended to mean cannabis that has had one or more compounds extracted from it.

Examples of compounds or classes of compounds that can be extracted from cannabis and therefore might form part of extract product produced in accordance with the invention, or might be absent from extracted cannabis product produced in accordance with the invention, include, but are not limited to, terpenes, cannabinoids, waxes, fatty acids, sugars, flavonoids, and chlorophyll.

Specific examples of terpenes include, but are not limited to, myrcene, limonene, linalool, and caryophyllene.

Specific examples of cannabinoids include, but are not limited to, tetrahydrocannabinol (THC), cannabidiol (CBD), tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA), tetrahydrocannabivarin (THCV), cannabigerol (CBG), and cannabinol (CBN).

Specific examples of waxes include, but are not limited to, complex mixtures that comprise hydrocarbons such as n-heptosane and n-nonasane.

Specific examples of fatty acids include, but are not limited to, palmitic (hexadecenoic acid) and hexanoic acid, and their conjugate bases and derivatives.

Specific examples of sugars include, but are not limited to, fructose, arabinose, glucose, maltose and sucrose. Specific examples of flavonoids include, but are not limited to, aglycones, glycosides and other derivatives of apigenin, luteolin, kaempferol and quercetin.

The method according to the invention advantageously enables selectively extracting two or more different products from cannabis. By "selectively" extracting the two or more different products is meant the extraction system (discussed in more detail below) used in a given extraction step is uniquely tailored to extract from the cannabis certain products while not extracting other products, thereby affording extraction selectivity.

In one embodiment, one or more products selected from terpenes, cannabinoids, waxes, fatty acids, sugars, flavonoids, and chlorophyll are selectively extracted from or retained in the cannabis at an efficiency of at least 50 wt. %, or at least 60 wt. %, or at least 70 wt. %, or at least 80 wt. %, or at least 90 wt. %, or at least 95 wt. %, relative to the amount of the one or more products in the cannabis before undergoing extraction.

As the method of the invention makes use of steam extracted cannabis or includes an initial steam extraction step, the steam extracted cannabis that is subsequently subjected to the solvent extraction steps will have had terpenes extracted at least at an efficiency as outlined above.

The method may be performed such that sugars and flavonoids are extracted from the cannabis while cannabinoids are retained in the extracted cannabis.

In one embodiment, sugars and flavonoids are extracted from the cannabis while cannabinoids are retained in the extracted cannabis.

In a further embodiment, at least 50 wt. %, or at least 60 wt. %, or at least 70 wt. %, or at least 80 wt. %, or at least 90 wt. %, or at least 95 wt. % of sugars and flavonoids are extracted from the cannabis while at least 50 wt. %, or at least 60 wt. %, or at least 70 wt. %, or at least 80 wt. %, or at least 90 wt. %, or at least 95 wt. % of cannabinoids are retained in the extracted cannabis, relative to the amount of sugars, flavonoids and cannabinoids in the cannabis before undergoing extraction. The method involves providing steam cannabis and a first extraction solvent system in a container. The container will therefore not only be suitable for holding the cannabis during the extraction process, but also suitable for being exposed to the extraction system used (steam and/or solvent). Generally, the container will be manufactured from stainless steel or glass.

The container primarily functions as a vessel that retains the cannabis and enables it to be extracted by the extraction system. The same container or different containers may be used for each extraction step. Where the same container is used, the method advantageously enables the extracted cannabis obtained in each extraction step to simply be retained in the container for use in subsequent extraction steps. In that case, after an extraction step a given extraction system is removed from the container to leave the extracted cannabis in the container ready to be subjected to the next extraction step.

There is no particular limitation on the shape of the container that can be used provided it can hold the cannabis and enable the cannabis to be extracted by the extraction system. For example, the container may present in a tubular shape having at least one sealable opening for introducing the cannabis to be extracted and removing the extracted cannabis. The container will also generally have means, for example an inlet port, for introducing the extraction system into the container and also a means, for example an outlet port, for removing the extraction system from the container. The means for introducing and removing the extraction system into/from the container may be the same or may be separate and located at opposite ends of the container, for example at opposite ends of a tubular structure.

There is no particular limitation on the size of the container that can be used. The method of the invention can be performed on a laboratory scale and advantageously scaled up through to an industrial scale. For example, the volume of the container might range from about 100 mis or less through to about 1000 ltrs, or about 2000 ltrs, or about 3000 ltrs, or about 4000 ltrs, or about 5000 ltrs. The steam extracted cannabis and the first extraction solvent system may be introduced into the container separately or simultaneously.

Generally, the steam extracted cannabis will be introduced into the container first, followed by the first extraction solvent system.

The feedstock or source cannabis used to make the steam extracted cannabis that it is used in the method of the invention can advantageously be undried cannabis, partially dried cannabis, or dried cannabis.

As used herein, dried cannabis is intended to mean cannabis having a moisture content of less than about 15 weight %, partially dried cannabis is intended to mean cannabis having a moisture content ranging from about 15 weight % to about 50 weight % and undried cannabis is intended to mean cannabis having a moisture content greater than about 50 weight %.

Undried cannabis might also more commonly be referred to as freshly harvested cannabis.

The source cannabis used to make the steam extracted cannabis may be provided frozen, at room temperature or even heated above room temperature if desired.

In one embodiment, the source cannabis that is steam extracted has a moisture content of greater than about 50 weight %.

For example, a container may be located at a cannabis growing site and freshly harvested cannabis directly introduced into the container at the growing site. The container containing the cannabis can then be transported to an extraction facility where it is used in accordance with the method of the invention by subjecting it to steam extraction and then using the so formed steam extracted cannabis product in combination with the first extraction solvent system.

The steam extracted and source cannabis used in accordance with the method can have a varied water content. In one embodiment, the stream extracted cannabis provided with the first extract solvent system in the container has a moisture content ranging from about 15 weight % to about 50 weight %.

In a further embodiment, the steam cannabis provided with the first extract solvent system in the container has a moisture content of less than 15 weight %.

Where the steam extracted or source cannabis used in accordance with the invention has been dried or partially dried, it can be dried using techniques well-known to those skilled in the art. For example, the cannabis can be dried or partially dried by air drying or freeze- drying.

The first extraction solvent system used in accordance with the invention comprises a mixture of two or more miscible solvents that has a first dielectric constant.

An "extraction solvent system" used in accordance with the invention is a combination or mixture of two or more miscible solvents, with the numerical descriptors first, second, third etc being used to distinguish subsequent extraction solvent systems having a different composition that provide for different dielectric constants. For example, the first extraction solvent system may have a Dk A, the second extraction solvent system may have a Dk B and the third extraction solvent system may have a Dk C etc, with A, B and C being different.

An extraction solvent system having the same Dk may be used multiple times within a given method sequence. For example, the method may be performed by using first extraction solvent system having Dk A, followed by a second extraction solvent system having Dk B, followed by a third extraction solvent system having a Dk C, followed by the first solvent extraction system used a second time having the Dk A. As will be discussed in more detail below, an extraction solvent system having a specific Dk may be provided by different combinations of two or more miscible solvents. In other words a given Dk may be provided by more than one combination of different two or more miscible solvents.

By a given extraction solvent system comprising a mixture of two or more "miscible" solvents is meant the combination of solvents used provides for a single liquid phase. Accordingly, it will be appreciated the extraction solvent system used in accordance with the method of the invention is a single phase liquid extraction solvent system.

The mixture of two or more miscible solvents that provides for a given extraction solvent system used in accordance with the invention has a dielectric constant (Dk).

Reference herein to a dielectric constant of a given extraction solvent system means a calculated dielectric constant of the solvent mixture intended for use in the method. The dielectric constant of the mixture of two or more miscible solvents that makes up a given extraction solvent system is determined by calculating the product of the volume fraction and dielectric point for each of the components and finding the sum of those products using the following equation:

Dk (extraction solvent system) = E (Dki x (pi)

Where the values for i correspond with each of the component miscible solvents; 1,2 etc., and Dki is the dielectric constant for the respective solvents that make up the system and (p is the volume fraction for each component, both being at the temperature of extraction.

For example the Dk of a 20% ethanol (E): 80% water (W) (v/v) at 20°C may be calculated as follows:

Dk (E20% : W80) = Dk E(20°C) x (p E(20°C) + DkW(20°C) x (p W (20°C)

Dk (E20% : W80) = (25.02 x 0.2) + (80.37 x 0.8) = 69.3 Those skilled in the art will appreciate that dielectric constants can vary with temperature. Accordingly, a dielectric constant used in accordance with the invention means that calculated for the temperature at which the method of the invention is to be performed. For example, if the method of the invention is to be performed at 25° C, then the dielectric constant for each extraction solvent systems used will be that calculated for 25° C.

Dielectric constants for relevant solvents at various temperatures are well known to those skilled in the art and can be readily used in calculating the dielectric constant of the extraction solvent systems used in accordance with the invention. Further detail on dielectric constants for solvents suitable for use in accordance with the invention is provided below.

As discussed herein, the first extraction solvent system has a first dielectric constant, the second extraction solvent system has a second dielectric constant, the third extraction solvent system has a third dielectric constant, and so on. The first, second, third etc dielectric constants are different.

Being able to tailor the extraction solvent systems to have different dielectric constants advantageously enhances the ability to selectively extract products from the cannabis.

As those skilled in the art will appreciate, the dielectric constant of a solvent system such as the extraction solvent systems used in accordance with the present invention is a measure of the solvent's polarity. The higher the dielectric constant of a solvent system, the more polar it is. For example, a polar substance such as water is commonly expressed as having a dielectric constant of about 80 and a nonpolar substance such as hexane is commonly expressed as having a dielectric constant of about 2 (at about 20° C).

While not a precise science, polar products tend to be more readily extracted using polar solvents and nonpolar products tend to be more readily extracted using nonpolar solvents.

Products that can be extracted from cannabis have in their own right a range of different polarities. Conventional solvent-based processes for extracting products from cannabis typically make use of simple solvent systems that are prone to extracting a broad spectrum of products from cannabis. Such broad spectrum product extracts derived by conventional means are then typically subjected to one or more purification steps post extraction to isolate desired products/remove non-target products, the process of which introduces complexity and cost.

In contrast, the method of the present invention employs steam extracted cannabis in combination with unique extraction solvent systems having tailored and different dielectric constants that enhances product extraction selectivity and minimises post extraction product processing. The method can be employed to selectively extract undesirable products from the cannabis in one extraction step, with the extracted product of that step(s) being set aside. The method then involves a subsequent extraction step tailored to extract from the previously extracted cannabis a desired product, with the resulting extracted product being substantially free of undesirable product and thereby not requiring subsequent post extraction purification.

The difference between the dielectric constant values employed will depend upon the selectivity required for a given extraction process. Generally, the extraction solvent systems used in accordance with the invention will be prepared to have a dielectric constant that differs by at least 5%.

In one embodiment, the dielectric constant of a given extraction solvent system differs by at least about 5%, or at least about 10%, or at least about 15% relative to the dielectric constant of an extraction solvent system used in a proceeding extraction step.

For example, in another embodiment the dielectric constant of the second extraction solvent system differs by at least about 5%, or at least about 10%, or at least about 15% relative to the dielectric constant of the first extraction solvent system.

In a further embodiment the dielectric constant of the third extraction solvent system differs by at least about 5%, or at least about 10%, or at least about 15% relative to the dielectric constant of the second or first extraction solvent systems.

In one embodiment, the dielectric constant of each extraction solvent system used is different by at least 5%, or at least about 10%, or at least about 15%.

The extraction solvent systems used in accordance with the present invention will generally have a dielectric constant ranging from about 25 to about 85.

Those skilled in the art will select a suitable dielectric constant for a given extraction solvent system depending upon the intended products to be extracted.

In one embodiment, the first extraction solvent system has a dielectric constant ranging from about 85 to about 75 or about 80 to about 75 and the second extraction solvent system has a dielectric constant ranging from about 75 to about 65 or about 70 to about 65.

In another embodiment, the first extraction solvent system has a dielectric constant ranging from about 75 to about 65 and the second extraction solvent system has a dielectric constant ranging from about 60 to about 40.

In a further embodiment, the first extraction solvent system has a dielectric constant ranging from about 75 to about 68 and the second extraction solvent system has a dielectric constant ranging from about 55 to about 44.

In one embodiment, the first extraction solvent system has a dielectric constant ranging from about 85 to about 75 or about 80 to about 75, the second extraction solvent system has a dielectric constant ranging from about 75 to about 65 or about 70 to about 65, and the third extraction solvent system has a dielectric constant ranging from about 60 to about 40 or about 55 to about 40.

Provided the combination of solvents used are miscible, there is no particular limitation on the range of solvents that can be used to provide for the extraction solvent systems. Given the diversity of compounds present in cannabis, the range of solvents that can be used is extensive. Having regard to the products to be extracted from the cannabis, those skilled in the art can readily select a suitable combination of two or more miscible solvents for the task. The solvents may be nonpolar or polar. The polar solvents may be polar aprotic or polar protic.

Those skilled in the art will be able to (i) select two or more solvents to provide for a miscible combination, and (ii) use readily available data to calculate the dielectric constant for the resulting solvent mixture/combination.

Examples of suitable solvents include, but are not limited to, C5-C10 alkanes, diethylether, chloroform, ethyl acetate, dichloromethane, acetone, acetonitrile, C1-C6 alcohols, C2-C4 diols, water, vegetable oil, glycerol (for example vegetable glycerol) and ethyl lactate.

In one embodiment, the two or more miscible solvents are selected from C5-C10 alkanes (e.g. pentane, hexane, heptane, octane, nonane and decane), diethylether, chloroform, ethyl acetate, dichloromethane, acetone, acetonitrile, C1-C6 alcohols (e.g. methanol, ethanol, propanol, butanol, pentanol and hexanol), C2-C4 diols, (e.g. ethylene glycol, propylene glycol, and butylene glycol), water, vegetable oil (e.g. cotton seed oil, ground nut oil, mustard seed oil and sunflower oil), glycerol (e.g. vegetable glycerol) and ethyl lactate.

In a further embodiment, the two or more miscible solvents are selected from ethanol, ethyl acetate, propylene glycol, glycerol, water and ethyl lactate

The Dk for such suitable solvents at 20° C is shown in the table below.

The different dielectric constants of the extraction solvent systems used in accordance with the invention is provided by using a different mixture of the two or more miscible solvents.

That different mixture may itself be provided by (i) replacing one or more of the two or more miscible solvents with a different miscible solvent, or (ii) changing the ratio of the same two or more miscible solvents used previously. In a given extraction sequence, the different dielectric constants may of course be provided using a combination of (i) and (ii).

For example, the required different dielectric constants may be provided by using a first extraction solvent system comprising water and ethanol to provide a Dk A, followed by using a second extraction solvent system comprising water and glycerol to provide a Dk B, where A and B are different.

As a further example, the required different dielectric constants may be provided by using a first extraction solvent system comprising water and ethanol at a defined or known ratio to provide a Dk A, followed by using a second extraction solvent system also comprising water and ethanol, but at a different ratio to that used in the first extraction solvent system to provide a Dk B, where A and B are different.

In one embodiment, the different dielectric constant of an extraction solvent system is provided by using the mixture of the same two or more miscible solvents at a different ratio to the ratio used previously.

As an example of providing the different the dielectric constant using the same combination of miscible solvents at different ratios, the method may use an extraction solvent system based on an ethanol and water composition and have the following extraction sequence and extraction solvent system ratio profile:

The present invention might also be described as providing a method for selectively extracting two or more different products from cannabis; the method comprising:

(i) providing steam extracted cannabis and a first extraction solvent system in a container, the first extraction solvent system comprising a mixture of two or more miscible solvents in a defined ratio that has a first dielectric constant; (ii) maintaining the steam extracted cannabis in contact with the first extraction solvent system so as to promote extraction of a first product from the cannabis into the first extraction solvent system and produce solvent extracted cannabis;

(iii) separating the first extraction solvent system comprising the first product from the solvent extracted cannabis;

(iv) introducing into a container with the solvent extracted cannabis from step (iii) a second extraction solvent system comprising the mixture of two or more miscible solvents at a different ratio to that of the first extraction solvent system and having a different dielectric constant to that of the first extraction solvent system; and

(v) maintaining the solvent extracted cannabis in contact with the second extraction solvent system so as to promote extraction of a second product from the solvent extracted cannabis into the second extraction solvent system, wherein the second product has a different composition to the first product.

The method may further comprise:

(vi) separating the second extraction solvent system comprising the second product from the solvent extracted cannabis;

(vii) introducing into a container with the solvent extracted cannabis from step (vi) a third extraction solvent system comprising the mixture of two or more miscible solvents in a ratio that is different to that used in step (i) and (iv) and having a different dielectric constant to that used in step (i) and/or (iv);

(viii) maintaining the solvent extracted cannabis in contact with the third extraction solvent system so as to promote extraction of a third product from the solvent extracted cannabis into the third extraction solvent system, wherein the third product has a different composition to the first and second product.

In another embodiment, the different dielectric constant of an extraction solvent system is provided by replacing one or more of the two or more miscible solvents with a different miscible solvent. As an example of providing the different dielectric constant by replacing one or more of the two or more miscible solvents with a different miscible solvent, the method may use the following extraction sequence and extraction solvent system profile.

The present invention might also be described as providing a method for selectively extracting two or more different products from cannabis; the method comprising:

(i) providing steam extracted cannabis and a first extraction solvent system in a container, the first extraction solvent system comprising a mixture of two or more miscible solvents that has a first dielectric constant;

(ii) maintaining the steam extracted cannabis in contact with the first extraction solvent system so as to promote extraction of a first product from the cannabis into the first extraction solvent system and produce solvent extracted cannabis;

(iii) separating the first extraction solvent system comprising the first product from the solvent extracted cannabis;

(iv) introducing into a container with the solvent extracted cannabis from step (iii) a second extraction solvent system comprising a mixture of two or more miscible solvents having a different dielectric constant to that of the first extraction solvent system, wherein at least one of the two or more miscible solvents is different from that used in first extraction solvent system; and

(v) maintaining the solvent extracted cannabis in contact with the second extraction solvent system so as to promote extraction of a second product from the solvent extracted cannabis into the second extraction solvent system, wherein the second product has a different composition to the first product. The method may further comprise:

(vi) separating the second extraction solvent system comprising the second product from the solvent extracted cannabis;

(vii) introducing into a container with the solvent extracted cannabis from step (vi) a third extraction solvent system comprising a mixture of two or more miscible solvents having a different dielectric constant to that used in step (i) and (iv), wherein at least one of the two or more miscible solvents is different from that used in used in step (i) and/or (iv);

(viii) maintaining the solvent extracted cannabis in contact with the third extraction solvent system so as to promote extraction of a third product from the solvent extracted cannabis into the third extraction solvent system, wherein the third product has a different composition to the first and second product.

In one embodiment, the extraction solvent system (e.g. the first, second, third, etc) comprises ethanol and water.

In another embodiment, the extraction solvent system (e.g. the first, second, third, etc) comprises propylene glycol and water.

In further embodiment, the extraction solvent system (e.g. the first, second, third, etc) comprises glycerol and water.

In another embodiment, the extraction solvent system (e.g. the first, second, third, etc) comprises glycerol, propylene glycol and water

As discussed herein, the role and function of the extraction solvent system used in accordance with the invention is to provide a simple, convenient and efficient means of tailoring the dielectric constant of the solvent systems and thereby enable enhanced product extraction selectivity from cannabis. The ability to tailor a diverse range of dielectric constants stems from the extraction solvent system comprising two or more miscible solvents. While there is no particular limitation on the proportions of each solvent that is present in the mixture of the two or more miscible solvents, each solvent will be present in an amount that at least causes a change in the dielectric constant of the solvent composition to which it is added. In other words, each solvent in the mixture of two or miscible solvents will be present in an amount that should it be removed from the mixture it would cause a change in the resulting solvent(s) dielectric constant.

As a general guide only, each solvent present in the mixture of two or more miscible solvents will generally be present in an amount of at least 2 wt.%, or at least about 5 wt. %.

For example, each of the two or more miscible solvents may be present in an amount ranging from about 2 wt.% to about 98 wt %, or about 3 wt.% to about 97 wt %, or about 4 wt.% to about 96 wt %, or about 5 wt.% to about 95 wt %, or about 6 wt.% to about 94 wt %, or about 7 wt.% to about 93 wt %, or about 8 wt.% to about 92 wt %, or about 9 wt.% to about 91wt %, or about 10 wt.% to about 90 wt %.

Where the two or more miscible solvents that make up the first extraction solvent system are present in a defined ratio, as mentioned that ratio can be adjusted to provide for the subsequent extraction solvent systems having a different dielectric constant. By being "defined" is meant the ratio is known. It must of course be known in the sense it is subsequently adjusted to be at a different ratio.

There is no particular limitation on the starting defined ratio of the first extraction solvent system or the adjusted ratios of the subsequent extraction solvent systems. The ratio of solvents used in a given extraction solvent system will be selected based on the solvent types being used, the dielectric constant to be achieved and also the nature of compounds that is to be extracted from the cannabis.

Those skilled in the art will be able to not only select the two or more miscible solvents to be used in the extraction solvent system but also the ratio of those solvents to be used in the first and subsequent extraction solvent systems. As an example only, where the extraction solvent system is based on an ethanol and water composition, the first extraction solvent system might have an ethanol to water weight % ratio of about 10:90 (Dk 74 at 20° C), with the following three extraction solvent systems having a weight % ratio of about 50:50 (Dk 49 at 20° C), 70:30 (Dk 39 at 20° C) and 90:10 (Dk 29 at 20° C), respectively.

As an example only, where the extraction solvent system is based on a propylene glycol and water composition, the first extraction solvent system might have an propylene glycol to water weight % ratio of about 25:75 (Dk 69 at 20° C), with the following two extraction solvent systems having a weight % ratio of 60:40 (Dk 52 at 20° C), and 90:10 (Dk 37 at 20° C), respectively.

As an example only, where the extraction solvent system is based on a glycerol, propylene glycol and water composition, the first extraction solvent system might have a glycerol to propylene glycol to water weight % ratio of about 25:5:70 (Dk 70 at 20° C), with the following two extraction solvent systems having a weight % ratio of 80:5:15 (Dk 48 at 20° C), and 15:75:10 (Dk 38 at 20° C), respectively.

Where the different dielectric constant of an extraction solvent system is provided by replacing one or more of the mixture of two or more miscible solvents with a different miscible solvent, the first extraction solvent system might comprise glycerol and water at a weight % ratio of about 25:75 (Dk 72 at 20° C), with the second extraction solvent system comprising ethanol and water at a weight % ratio of about 45:55 (Dk 52 at 20° C), and a third extraction solvent system comprising propylene glycol and water at a weight % ratio of about 90:10 (Dk 37 at 20° C).

In accordance with the method, the steam extracted cannabis is maintained in contact with the first extraction solvent system to promote extraction of a first product from the steam extracted cannabis into the first extraction solvent system. It will be appreciated the cannabis is maintained in contact with a given extraction solvent system within the container. The given extraction solvent system may be maintained in contact with the cannabis in the container and no flow through the contained or the extraction solvent system may be maintained in contact with the cannabis while flowing through the container. An extraction solvent system may be stirred or agitated while being maintained in contact with the cannabis.

For example, a fixed volume of a given extraction solvent system may be introduced into the container with the cannabis to remain in contact with the cannabis with or without being stirred or agitated. That extraction solvent system can be maintained in contact with the cannabis for a period of time sufficient to promote extraction of a product into the extraction solvent system. The extraction solvent system can then be removed from the container, together with the product that has been extracted into it, and thereby leave behind in the container solvent extracted cannabis. That so formed solvent extracted cannabis can be retained in the same container to undergo a subsequent extraction, or it can be transferred into a separate container to undergo a subsequent extraction.

Alternatively, a given extraction solvent system may be introduced into the container with the cannabis and pass through to be in flow contact with the cannabis. That extraction solvent system can be maintained in flow contact with the cannabis for a period of time sufficient to promote extraction of a product into the extraction solvent system. In that case, the extraction solvent system may flow through the container as part of a closed recirculating loop. The extraction solvent system can then be removed from the container and related flow paths, together with the product that has been extracted into it, and thereby leave behind in the container solvent extracted cannabis. That so formed solvent extracted cannabis can be retained in the same container to undergo a subsequent extraction, or it can be transferred into a separate container to undergo a subsequent extraction.

As a further alternative, a combination of the aforementioned extraction approaches may be adopted. For example, a fixed volume of extraction solvent system can be introduced into the container with the cannabis to remain in contact with the cannabis for a set period of time. That fixed volume of extraction solvent system can be caused to flow through and out of the container within a closed loop system so as to refill the container with a further fixed volume portion of the extraction solvent system. The extraction solvent system can be alternated through such plug flow cycles numerous times to promote extraction of the product into the extraction solvent. The extraction solvent system can be removed from the container and related flow path, together with the product that has been extracted into it, and thereby leave behind the container solvent extracted cannabis. That so formed solvent extracted cannabis can be retained in the same container to undergo a subsequent extraction, or it can be transferred into a separate container to undergo a subsequent extraction.

There is no particular limitation on the amount of time in which the cannabis is to be maintained in contact with the extraction solvent system to promote extraction of a product from the cannabis into the extraction solvent system. The amount of time required in practice will vary depending upon factors known to those skilled in the art such as the surface area of the cannabis being extracted, the nature of the extraction solvent system being used and the type of product being extracted from the cannabis.

Those skilled suitably adjust the amount of time in which the cannabis is to be maintained in contact with the extraction solvent system to promote extraction of a given product.

Generally, a given extraction solvent system will be maintained in contact (static or in flow) with the cannabis for a period of time ranging from about 30 minutes to about 4 hours.

A given extraction solvent system used in the method of the invention may be at room temperature or it may be heated or cooled as required, relative to room temperature.

There is no particular limitation on the temperature at which the method of the invention may be performed provided the extraction solvent systems selected are appropriate. The temperature at which the method is performed can sometimes be limited by the type of extraction solvent systems used. Those skilled in the art will be able to select a suitable temperature for the extraction solvent systems being employed. Generally, the temperature of the extraction solvent systems used in accordance with the invention range from about -20° C to about 50° C, or from about 10° C to about 40° C, or from 20° C to about 30° C.

Having exposed the cannabis to the first extraction solvent system for a time sufficient to promote extraction of the first product from the cannabis into the first extraction solvent system, two products are produced. One of those is of course the first product extracted from the cannabis into the extraction solvent system. The other is the solvent extracted cannabis per se.

The first extraction solvent system comprising the first product is separated from the solvent extracted cannabis. That separation can be undertaken by any suitable means. For example, the solvent extracted cannabis can be removed from the container leaving the first extraction solvent in the container or alternatively the first extraction solvent system can be removed from the container leaving the solvent extracted cannabis in the container.

It can often be advantageous to remove the first extraction solvent system comprising the first product from the container so as to retain in the container the solvent extracted cannabis that is to be subjected to additional extraction steps in/using the same container.

The separated first extraction solvent system may contain a product that is to be subsequently isolated for further use or a product that is of no practical commercial use and can subsequently be discarded.

The separated solvent extracted cannabis produced in step (iii) of the method is subjected to at least a second extraction solvent system for the purpose of extracting at least a second product from it.

The extraction process using the second extraction solvent system is essentially conducted in the same manner as that undertaken using the first extraction solvent system as herein described, but the second extraction solvent system has a different dielectric constant to that of the first extraction solvent system used in step (i). Also, a second product that has a different composition to the first product is extracted from the solvent extracted cannabis produced in step (i) into the second extraction solvent system.

As with the first extraction solvent system according to step (iii), the second extraction solvent system comprising the second product will typically be separated from the first extraction solvent system.

The separated second extraction solvent system may contain a product that is to be subsequently isolated for further use or a product that is of no practical commercial use and can subsequently be discarded.

The further solvent extracted cannabis produced after using the second extraction solvent system can be subjected to one or more further extractions using subsequent extraction solvent systems, such as third, fourth, fifth etc extraction solvent systems.

The method in accordance with the invention might therefore at least involve additional steps

(vi)-(viii):

(vi) separating the second extraction solvent system comprising the second product from the solvent extracted cannabis;

(vii) introducing into a container with the solvent extracted cannabis from step (vi) a third extraction solvent system comprising a mixture of two or more miscible solvents that has a different dielectric constant to that of the first extraction solvent system used in step (i) and the second extraction solvent system used in step (iv);

(viii) maintaining the solvent extracted cannabis in contact with the third extraction solvent system so as to promote extraction of a third product from the solvent extracted cannabis into the third extraction solvent system, wherein the third product has a different composition to the first and second product. Alternatively, the further solvent extracted cannabis produced after using the second extraction solvent system can be separated/isolated and itself used as a commercial product or possibly discarded.

Where third, fourth, fifth etc extraction solvent systems are used in accordance with the method invention, the steps involved will be essentially the same as those herein described in respect of the first and second extraction solvent systems.

The method in accordance with the invention produces two main types of products, namely those extracted into each of the extraction solvent systems used and the solvent extracted cannabis itself.

Each product extracted into each of the extraction solvent systems (i) may comprise a single compound or be made up of two or more different compounds, and (ii) is different in the sense it contains one or more different compounds and/or or a different ratio of the same compounds, relative to a product extracted into other extraction solvent systems.

Products extracted into each of the extraction solvent systems may or may not be targeted for commercial use.

A product extracted into a given extraction solvent system may be isolated from the extraction solvent system using techniques well-known to those skilled in the art. For example, solvent extraction, precipitation, crystallisation and distillation techniques may be employed.

A product derived from the method of the invention may also be purified using techniques well-known to those skilled in the art. For example, precipitation, crystallisation, distillation and chromatography techniques may be employed.

Extraction solvent systems used in accordance with the invention can advantageously be recycled for subsequent use. For example, a product extracted into a given extraction solvent system can be isolated from the extraction solvent system, the process of which may inherently purify the solvents that make up that system. Alternatively, previously used extraction solvent system can be purified for subsequent reuse using techniques well-known to those skilled in the art. For example, distillation may be employed.

Having regard to considerations of solubility and polarity of products to be extracted or not extracted from the cannabis, those skilled will be able to select a suitable extraction solvent system(s) for use in accordance with the invention to selectively extract or not extract such products from the cannabis.

The cannabis feedstock used in accordance with the invention is steam extracted cannabis.

Prior to undertaking step (i), the method might further comprise introducing steam into a container comprising source cannabis where the steam (a) extracts from the cannabis a steam extracted product that has a different composition to the extraction solvent system extracted products produced in subsequent steps, and (b) affords steam extracted cannabis, wherein the steam extracted cannabis is used as the steam extracted cannabis in step (i).

A step of subjecting the cannabis to steam extraction can advatageously promote decarboxylation of acid cannabinoids, such as tetrahydrocannabinolic acid (THCA), into the neutral cannabinoids, such as THC.

For such an embodiment, the cannabis that is subjected to the steam extraction may be dried, partially dried or undried source cannabis. The used cannabis may also be frozen, at room temperature or heated above room temperature.

Accordingly, in some embodiments the method may derive from the cannabis a steam extracted product. Such a steam extracted product may be collected using techniques well- known to those skilled in the art. For example, conventional steam distillation techniques can be employed. In that case, steam is typically passed through the cannabis located within the container. On passing through the cannabis the steam liberates soluble and/or volatile products from the cannabis which carry through with the steam and are subsequently collected typically by condensing the steam into liquid water. Product extracted from the cannabis by the steam may be insoluble in the condensed liquid water and consequently phase separate so as to be readily collected, for example using a Clevenger apparatus or simple decantation.

A steam extracted product produced in accordance with the method of the invention might, for example, primarily comprise terpenes, which include, but are not limited to, caryophyllene, pinene, and myrcene, and terpenoids such as linalool and eucalyptol (1,8 cineole).

The steam extracted cannabis remaining within the container after steam extraction will typically have had most if not all cannabinoid acids (e.g. THCA) present converted into neutral cannabinoids (e.g. THC).

Steam extraction is typically conducted for a time ranging from about 30 minutes to about 12 hours, 30 minutes to about 8 hours, 30 minutes to about 6 hours, 30 minutes to about 4 hours, or from about 30 minutes to about 3 hours, or from 30 minutes to about 2 hours.

To assist with describing embodiments of the invention, reference is made to Figure 1 that illustrates a schematic representation of equipment that may be used to perform the present invention. Figure 1 shows a container or extraction chamber (10) that contains the steam extracted cannabis (not shown). A first extraction solvent system having a Dk A as herein described may be contained within the balance tank (20) and transferred into the extraction chamber (10) using pump (30) via transfer line (40). The first extraction solvent system may be retained in a static fashion within extraction chamber (10) or continuously pumped through the extraction chamber (10) so as to be retrieved back into balance tank (20) via transfer line (50). If required, the first extraction solvent system may be continuously recycled through the extraction chamber (10) using pump (30) and via transfer lines (40) and (50). After a suitable period of time a first product will be extracted from the cannabis into the first extraction solvent system. Upon completion of the extraction of the first extraction solvent system comprising the first product is removed from the extraction chamber (10) and optionally balance tank (20) via drain transfer lines (60) and (70). Solvent extracted cannabis remains within the extraction chamber (10). The resulting solvent extracted cannabis is extracted again using a second extraction solvent system having a Dk B as herein described using the same operation process as that described above in respect of the first extraction solvent system. Accordingly, the second extraction solvent system is located in balance tank (20). The second extraction solvent system affords a second product and also further extracted cannabis. The extraction process may continue on to using a third, fourth, fifth etc solvent extraction system as herein described. If desired, prior to undertaking extraction with the first extraction solvent system, cannabis contained within the extraction chamber (10) may source cannabis and be subjected to steam extraction to provide for the steam extracted cannabis used in the method of the invention. In that case, a steam generator (70) passes steam through transfer line (80) into the extraction chamber (10) that then moves out through to condenser (90). The condenser (90) is cooled using chilled water (100) that passes into the condenser and out through the condenser via drain transfer line (110). The steam entering condenser (90) carries with it volatile and/or water soluble compounds liberated from the cannabis and is subsequently condensed into liquid water and exits the condenser into a collection vessel (120). The collection vessel (120) comprises condensed water and steam extracted product from the cannabis. At least some of the steam extracted product may be insoluble in the condensed water and collected from condensed water by decantation. The resulting steam extracted cannabis may them be used in the solvent extraction steps described above.

Figure 2 illustrates the same equipment illustrated in Figure 1, but with an emphasis on the recycling of a given extraction solvent system through extraction chamber (10) containing the cannabis. Here a given extraction solvent system located in balance tank (20) is transferred using pump (30) through transfer line (40) into extraction chamber (10) and back into balance tank (20) via transfer line (50) in the direction of the large arrows (5).

Figure 3 illustrates the same equipment illustrated in Figure 1, but with an emphasis on the draining of a given extraction solvent system from the equipment after completion of an extraction. After completion of a given extraction, extraction solvent system comprising an extracted product may be drained from extraction chamber (10) and possibly balance tank (20) via drain transfer lines (60) and (70) in the direction of the large arrows (5). Figure 4 illustrates the same equipment illustrated in Figure 1, but with an emphasis on a steam distillation step undertaken prior to using a given extraction solvent system. A steam generator (70) passes steam through transfer line (80) into the extraction chamber (10) containing source cannabis and passing out through to condenser (90) in the direction of the large arrows (5). The condenser (90) is cooled using chilled water (100) that passes into the condenser and out through the condenser via drain transfer line (110). The steam entering condenser (90) carries with it volatile and/or water soluble compounds liberated from the cannabis and is subsequently condensed into liquid water and exits the condenser into a collection vessel (120). The collection vessel (120) comprises condensed water and steam extracted product from the cannabis. At least some of the steam extracted product may be insoluble in the condensed water and collected from condensed water by decantation. The resulting steam extracted cannabis produced can them be used in the solvent extraction steps shown in Figures 1-4.

The invention will hereinafter be described with reference to the following non-limiting examples.

EXAMPLES

Example 1

Method & Materials

180 grams of fresh hemp flower was collected and chopped to a particle size of roughly 5- 10mm. The material was packed into the extraction vessel and the extraction vessel was placed into the extraction apparatus. The material was steam distilled for 1 hour. The hydrosol was collected, with the essential oil floating to the top of the hydrosol. After the distillation the post distillation tea (the condensed steam inside the extraction vessel) was collected. Then the successive solvent washes were applied to the material in the extraction vessel. For each wash 800 ml of a solvent ratio was recirculated through the material for 2 hours and collected, and 200ml of the same solvent ratio was flushed through the material. Miscible Solvents used and prepared as in the table below

• Ethanol Solution of 94% ethanol and 6% H2O

• H ₂ O

Figure 5 shows the 800ml washes post extraction. As can be seen from Figure 5 the colour of the extraction changes through the process.

RESULTS

Chlorophyll

Chlorophyll which can be seen as a green colour in the extract did not become apparent until after the 70% wash. The solvent system allows for the extraction of desirable components prior to extracting chlorophyll. Hydrophilic (polar) Compounds Including Flavonoids

Hydrophilic (polar) compounds, which include water soluble components such as sugars and flavonoids, and that have short retention times in reversed phase HPLC separations that incorporate a non polar stationary phase, were selectively extracted from plant material in washes 1 and 2 (Dk=75). Water soluble (polar) compounds were generally not detected in extracts derived from subsequent washes employing different solvent systems.

Cannabinoids

Cannabinoids were not generally extracted until washes 3 and 4 (Dk=54) and were nearly all extracted after washes 5 and 6 (Dk=44). This extraction sequence produced a relatively clean cannabinoid rich extract that contained a very low level of non target compounds, such as flavonoids which were selectively removed in washes 1 and 2, and chlorophyll which was not extracted until washes 7 and 8 (Dk=33.5).

Example 2

Method & Materials

1500 grams of fresh hemp flower was collected and chopped to a particle size of roughly 5- 10mm. The material was tested for CBD and THC levels prior to the extraction process to determine a baseline of cannabinoids present in the biomass. The material was packed into the extraction vessel and the extraction vessel was placed into the extraction apparatus.

The material was steam distilled for 1 hour. The hydrosol was collected, with the essential oil floating to the top of the hydrosol.

Then the successive solvent washes were applied to the material in the extraction vessel;

800 ml of a solvent ratio was recirculated through the material for 2 hours and then collected prior to starting the next wash. Miscible Solvents used and prepared as in the table below

• Ethanol Solution of 94% ethanol and 6% H2O

• H ₂ O

The material was tested for CBD and THC levels post the extraction process to determine if the process was successful in extracting the cannabinoids.

Figure 6 shows the 5 washes post extraction. As can be seen in Figure 6 the colour of the extraction changes through the process and there doesn’t appear to be any chlrophyl present in the washes.

RESULTS

Chlorophyll

Chlorophyll which can be seen as a green colour was not extracted in visually detectable quantities by the extraction sequence (washes 1 and 2, Dk=70; washes 3 to 5, Dk=49) which indicates that the extraction of desirable components without extraction of chlorophyll is possible using this protocol. Cannabinoids

The table directly below shows the test results of CBD and THC present in the plant material prior to the solvent extraction sequence.

The Table directly below shows the test results of CBD and THC present in the plant material after the solvent washes. This extraction sequence extracted 91.35% of the available cannabinoids. Bulked extracts derived from washes 3 to 5 (Dk= 49) which contained the cannabinoids were devoid of, or contained insignificant levels of flavonoids and chlorophyll.

SUBSTITUTE SHEET (RULE 26) The graph directly below shows the abundance of Cannabinoids in washes 3-5.

T17 W3-W5

Example 3

Method & Materials

1500 grams of fresh hemp flower was collected and dried. Dried flower was chopped to a particle size range of 5-10mm. Baseline CBD and THC levels in biomass were determined prior to the extraction process. The material was packed into the extraction vessel and the extraction vessel was placed into the extraction apparatus. The material was steam distilled for 1 hour. The hydrosol was collected, with the essential oil floating to the top of the hydrosol. After the distillation the post distillation tea (the condensed steam inside the extraction vessel) was collected.

Then the successive solvent washes were applied to the material in the extraction vessel. For each wash 8600 ml of a solvent ratio was recirculated through the material for 2 hours and collected. Miscible Solvents used and prepared as in the table below

• Ethanol Solution of 94% ethanol and 6% H2O

• H ₂ O

The material was tested for CBD and THC levels post the extraction process to determine if the process was successful in extracting the cannabinoids.

CBD and THC levels were determined in the washes and plant material after the extraction process to quantify the extraction efficiency of cannabinoids.

RESULTS

Cannabinoids

The table directly below shows the analytical results for CBD and THC content of the plant material prior to the solvent washes. CERTIFICATE OF ANALYSIS The table directly below shows the CBD and THC contents of the plant material after three solvent washes. The wash sequence extracted 83.5% of the primary cannabinoids (CBD + THC) from the plant material.

CERTIFICATE OF ANALYSIS * Assay by GC (FID detection)

Example 4

Method & Materials Two 50 gram samples of fresh hemp flower were collected and chopped to a particle size of roughly 5- 10mm.

SUBSTITUTE SHEET (RULE 26) The first sample was subjected to a 60 minute steam treatment prior to extraction washes. The second sample was not steam extracted. Each of the samples was packed into the extraction vessel and the extraction vessel was placed into the extraction apparatus. Baseline CBD and THC levels in biomass were determined prior to the steam treatment and extraction washes, respectively. Extraction was performed in a Schott bottle using a propylene glycol/ water (washes 1 and 2) and ethanol/ water (washes 3,4 and 5) solvent systems. A solvent to sample ratio of 10: 1 (v/w) was applied in all washes. Wash durations were 2 hours. Solvent was circulated using a magnetic stirrer. After each wash the extract was passed through a Buchner funnel and collected.

Successive solvent washes were applied to the material in the extraction vessel. Details of washes are shown in the table directly below.

CBD and THC levels were determined in the washes and plant material after the extraction process to determine the efficiency of extraction of cannabinoids.

RESULTS

Cannabinoids

The table directly below shows the analytical results for CBD and THC content of the plant material used in the sample that was steam extracted prior to the solvent washes. CERTIFICATE OF ANALYSIS

*Assay by GC (FID detection), calculated as A9-THC The table directly below shows the test results of CBD and THC present in the steam treated plant material after the 5 washes that involved 2 different binary solvent combinations. The wash sequence extracted over 97.5% of the cannabinoids (CBD + THC) from the plant material. CERTIFICATE OF ANALYSIS The table directly below shows the analytical results for CBD and THC content of the plant material used in the sample that was not subjected to steam treatment prior to the solvent washes.

SUBSTITUTE SHEET (RULE 26) CERTIFICATE OF ANALYSIS

The table directly below shows the test results of CBD and THC present in the plant material after the 5 washes that involved 2 different binary solvent combinations but did not have a prior steam treatment. The wash sequence extracted over 93.5% of the cannabinoids (CBD + THC) from the plant material. This non-steam treated extraction sequence extracted approximately 4% less cannabinoids than the sample that was subjected to a steam pretreatment and the same solvent wash sequence.

CERTIFICATE OF ANALYSIS * Assay by GC (FID detection)

SUBSTITUTE SHEET (RULE 26) Example 5

Method & Materials

Two 1500 gram samples of fresh hemp flower were collected and chopped to a particle size of roughly 5- 10mm.

The first sample was subjected to a 60 minute steam treatment prior to extraction washes. The second sample was not treated with steam. Each of the samples was packed into the extraction vessel and the extraction vessel was placed into the extraction apparatus. Baseline CBD and THC levels in biomass were determined prior to the steam treatment and extraction washes, respectively.

Baseline CBD and THC levels in biomass were determined prior to the extraction process. For the steam treatment sample the hydrosol was collected, with the essential oil floating to the top of the hydrosol. After the distillation the post distillation tea (the condensed steam inside the extraction vessel) was collected.

For comparison purposes successive solvent washes were applied to the steam treated and unsteamed material in the extraction vessel using the same solvent conditions. Each of the 8600 ml washes of a solvent ratio was recirculated through the material for 2 hours and collected. Successive solvent washes were applied to the material in the extraction vessel.

Details of washes are shown in the table directly below.

Miscible Solvents used and prepared as in the table below

• Ethanol Solution of 94% ethanol and 6% H2O

• H ₂ O

The material was tested for CBD and THC levels following the extraction process to determine the efficiency of process at extracting the cannabinoids.

RESULTS

Cannabinoids

The table directly below shows the analytical results for CBD and THC content of the sample that was treated with steam prior to the solvent extraction sequence.

The Table directly below shows the test results of CBD and THC present in the plant material after the steam pre-treatment and sequence of solvent washes. The extraction sequence consisting of steam pre-treatment followed by aqueous ethanol washes extracted 91.35% of the cannabinoids present in the flower tissue.

SUBSTITUTE SHEET (RULE 26)

The table directly below shows the analytical results for CBD and THC content of the plant material used in the sample that was not subjected to steam treatment prior to the solvent washes.

CERTIFICATE OF ANALYSIS

The table directly below shows the test results of CBD and THC present in the plant material after the 5 solvent washes but did not have a prior steam treatment. The wash sequence extracted over 79.5% of the cannabinoids (CBD + THC) from the plant material. This nonsteam treated extraction sequence extracted approximately 12% less cannabinoids than the sample that was subjected to a steam pre-treatment and the same solvent wash sequence.

SUBSTITUTE SHEET (RULE 26) CERTIFICATE OF ANALYSIS The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

SUBSTITUTE SHEET (RULE 26)