Botanical drug substance

The present invention relates to a botanical drug substance (BDS) for incorporation into a medicament. It also applies to BDS of a given purity for use in pharmaceutical preparations. In particular, it concerns BDS containing cannabinoids obtained by extraction from hemp.

In PCT / GB02 / 00620 the applicant discloses a method of producing a herbal drug extract (botanical drug substance) from medicinal cannabis. The method includes:

1. a heating step to decarboxylate the acid form of the cannabinoids to their neutral form,

2. first extraction with a specified volume of liquid carbon dioxide in 6-8 hours and

3. a step of reducing the proportion of non-target materials referred to as de-stearing, in which the waxes are precipitated.

More specifically, PCT / GB02 / 00620 discloses a method wherein: step 1 comprises heating cut hemp (2-3 mm) at 100-150 ° C for a period of time sufficient to allow decarboxylation, step 2 involves extracting CO2 using:

a) coarse-grained powder (particles pass through a 3 mm sieve),

b) packing density 0.3 i

c) supercritical conditions of 600 bar at 35 ° C for 4 hours, although evidenced other combinations of temperature and pressure between 10-35 ° C and 60-600 bar could be used (both supercritical and subcritical conditions ) and step 3 is carrying out an ethanol precipitation at -20 ° C for 24 hours and removing the wax material by filtration.

In the supercritical process disclosed in PCT / GB02 / 00620 the following were produced:

(a) a high THC extract containing:

60% tetrahydrocannabinol (THC),

1-2% cannabidiol (CBD)

4-5% of other trace cannabinoids including CBN (Quantitative yields were 9% w / w on the dry weight of medicinal cannabis) and

b) extract with high CBD content containing 60% CBD, 4% THC and 2% other cannabinoids (Quantitative yields were 9% w / w in relation to the dry weight of medicinal cannabis)

Since the BDS obtained is to be used in a pharmaceutical product, it is necessary that the process is safe, that it can be varied according to good manufacturing practice, and that it gives a high degree of product integrity and preferably also good yields.

The principle of supercritical liquid extraction (SFE) has been known since the work of Baron Cagniard de la Tour in 1822, when it was found that the gas-liquid interface disappeared when the temperature of some materials was increased by heating them in a closed glass vessel. In carrying out this initial work, a substance's tipping point was discovered for the first time. The critical point is the temperature above which the gas, liquid or solid phase coexistence of a given substance can occur. It was later found that once the substances were brought to or above critical temperatures and pressures, they could be used as improved solvents for the extraction and fractionation of complex mixtures.

The method is widely used in the treatment of diesel fuel and has been used, for example, for the purification and separation of vegetable oils and fish oils.

An attractive feature of SFE over traditional solvents is that the dissolving power (E °) can be varied by modifying the temperature and pressure above the critical point.

In a typical pressure-temperature diagram for a given substance, there are three lines that represent the equilibrium between the two phases. These lines meet at a triple point. The lines indicate the interface between the gaseous, liquid and solid states, and points along the lines indicate the equilibrium between the pairs of phases. For example, the vapor pressure (boiling point) curve starts at the triple point and ends at the critical point. The critical area begins at this point and the supercritical fluid is any substance that is above its critical temperature (Tc) and critical pressure (Pc). The critical temperature is thus the highest temperature at which a gas can be converted to a liquid by increasing the pressure, and the critical pressure is the highest pressure at which a liquid can be converted to a conventional gas by increasing the temperature. There is only one phase in this so-called critical region and it has some of the properties of both gas and liquid.

There are many solvents that can be used to extract active substances from plant materials. Table 1 shows the critical temperature and pressure of some of these solvents.

Table 1 - Critical conditions for solvents

<td>Solvents</td><td>Critical temperature (° C)</td><td>Critical pressures (bar)</td>

<td>Carbon dioxide</td><td> 31,1</td><td> 73,8</td>

<td>Ethane</td><td> 32,2</td><td> 48,8</td>

<td>Ethylene</td><td> 9,3</td><td> 50,4</td>

<td>Propane</td><td> 96,7</td><td> 42,5</td>

<td>Propylene</td><td> 91,9</td><td> 46,2</td>

<td>Cyclohexane</td><td> 280,3</td><td> 40,7</td>

<td>Isopropanol</td><td> 235,2</td><td> 47,6</td>

<td>Benzene</td><td> 289,0</td><td> 48,9</td>

<td>Toluene</td><td> 318,6</td><td> 41,1</td>

<td>p-xylene</td><td> 343,1</td><td> 35,2</td>

<td>Chlorotrifluoromethane</td><td> 28,9</td><td> 39,2</td>

<td>Trichlorofluoromethane</td><td> 198,1</td><td> 44,1</td>

<td>Ammonia</td><td> 132,5</td><td> 112,8</td>

<td>Water</td><td> 374,2</td><td> 220,5</td>

Carbon dioxide is used as the preferred solvent, which has a critical temperature of 31.1 ° C and a critical pressure of 73.8 bar.

Carbon dioxide is particularly preferred because it is available at low cost from many suppliers and can be recycled for reuse if desired. Any losses of CO2 are also neutral to the environment. Moreover, CO2 extraction is a safe production method and very sensitive particles can be extracted precisely.

The decisive factor to consider when initially selecting liquid CO2 as a solvent for the production of a standardized extract of high potency cannabis herb was the high degree of selectivity that could be achieved. In the CO2 system, it has been found that the solvating capacity can primarily be considered a function of density and temperature, with the solvent density being a more important factor.

By carefully controlling temperature and pressure below supercritical temperatures and pressures, the applicant has been able to isolate specific cannabinoid-rich lipophilic or hydrophilic fractions along with other ingredients that can be relatively easily isolated to obtain a botanical drug substance (BDS) that contains the desired ingredients in a form that it is pharmaceutically acceptable. In this way, ingredients known to be active substances can be separated from the complex mixtures that occur in the botanical raw material.

Moreover, very good batch-to-batch reproducibility can be achieved and undesirable components such as heavy metals, which may be present to a varying degree in the botanical raw material, can be left behind in the spent material.

Extraction conditions can also be modified to eliminate pesticide residues that may be present in the starting material.

The benefits of using subcritical conditions include the selective nature of the extraction. In contrast, in the case of SFE, it was found that the solvent, in addition to dissolving the desired cannabinoids, also disadvantageously dissolves other non-target materials that proved difficult to separate in a further purification step.

To explain, the density of subcritical CO2 is low and remains low, even with increasing pressure until the critical point of the system is reached. And so, when the subcritical solvating ability

Since CO2 is lower, a high degree of selectivity can be achieved since only the most soluble components are efficiently dissolved by CO2, in this case it is the cannabinoid fraction. The result is a relatively simple extract containing only a limited number of non-target compounds in addition to the cannabinoids, many of which can be removed relatively easily in an uncomplicated manner. In addition, cost savings from operating at relatively low pressures and temperatures are an additional benefit.

In contrast, above the critical temperature of 31 ° C, there is a significant increase in CO2 density since it is then in a supercritical fluid state. This results in a large increase in the solvating capacity of the solvent which, while generally advantageous in that more cannabinoids dissolve thus giving good yields, in fact proves to be disadvantageous as the reduced selectivity of the stronger solvent results in increased solubility of a range of non-target compounds. which makes the resulting extract more difficult to clean. In other words, this results in the production of more complex extracts in which the concentration of the target compound may be much weaker (ie the strength of the extract is decreased).

The present invention relates to a botanical drug substance that can be obtained from a botanical raw material of a cannabis plant with a high tetrahydrocannabinol (THC) content, which is characterized in that the above-mentioned botanical drug substance is an extract of a high-THC cannabis plant containing at least 60% cannabinoid ingredients and less than 40% non-cannabinoid ingredients not more than 5% CBD w / w in relation to the THC content and not more than 5% of cannabinoids other than THC and CBD in% w / w in relation to the THC content, with cannabinoid components containing at least 90% THC and non-cannabinoid components contain terpenes and reduced amounts of hydrocarbon and triglyceride waxes and plant pigments.

The present invention also relates to a botanical drug substance that can be obtained from a botanical raw material of a high-CBD hemp plant, characterized in that the above-mentioned botanical drug substance is an extract of a high-CBD hemp plant containing at least 60% cannabinoid components and less than 40% of non-cannabinoid ingredients, not more than 7.5% THC w / w in relation to the CBD content and not more than 5% of cannabinoids other than CBD and THC in% w / w in relation to the CBD content, while the cannabinoid components contain at least 85% CBD and the components do not -cannabinoids contain terpenes and reduced amounts of hydrocarbon and triglyceride waxes and plant pigments.

Preferably, the botanical drug substance contains no more than 4 ppb of aflatoxin.

Preferably, the botanical drug substance contains no more than 20 ppm of heavy metals.

Preferably, the botanical drug substance contains no more than 15% w / w residual solvents.

Preferably the residual solvent is ethanol.

₅

Preferably, the botanical drug substance contains no more than 10⁵ cfu / g TVC, no more than 10⁴ cfu / g of mushrooms, no more than 10³ cfu / g intestinal bacilli and other non-grammatical organisms and undetectable E. Coli, Salmonella or S. aureus.

Preferably, the botanical drug substance comprises at least 60% cannabinoids of which at least 90% is THC, 1.5% is CBD and the remainder is other secondary cannabinoids.

Preferably, the botanical drug substance comprises at least 60% cannabinoids, of which at least 85% is CBD, 3% is THC and the remainder is other secondary cannabinoids.

A botanical drug substance is an extract derived from a hemp plant material to which the definition of a botanical drug substance as given in the Draft Guideline for Industrial Botanical Drug Products, August 2000, U.S. Department of Health and Human Services, Administrative Food Center and Medicines for Drug Evaluation and Scientific Research A drug substance derived from one or more plants, algae or macroscopic fungi. It is produced from botanical raw materials by one or more of the following methods: pulverization, cultivation, squeezing, water extraction, ethanol extraction and other similar methods.

PL 226 646 B1

Plant material is defined as a plant or part of a plant (e.g. bark, wood, leaves, stems, roots, flowers, fruits, seeds, berries or parts thereof) as well as exudates, and includes material that falls under the definition of a botanical raw material in the Guidelines to Draft Guideline for Industrial Botanical Medicinal Products, August 2000, U.S. Department of Health and Human Services, Food and Drug Administration for Medicinal Products, Drug Assessment and Research.

Most often, but not necessarily, the plant material will be plant material or a botanical raw material derived from one or more cannabis plants.

The term hemp plant (hemp plants) covers wild-type true hemp as well as varieties thereof, including chemical varieties of hemp that naturally contain varying amounts of individual cannabinoids, Indian subspecies of true hemp, including varieties var. indica and var. kafiristanica, cannabis, as well as plants that are the result of genetic crosses, autocrosses or their hybrids. The term hemp plant material is therefore to be understood as including plant material derived from one or more hemp plants. For the avoidance of doubt, the hemp plant material is hereby stated to contain dry hemp biomass.

The method of extracting cannabinoids from plant material includes a decarboxylation step, extraction with liquid carbon dioxide (CO2) and a step of reducing the proportion of non-target materials in the extract, whereby extraction with liquid CO2 is carried out under subcritical conditions at a temperature of 5-15 ° C and a pressure of 50- 70 bar.

The above method can be used for the production of a cannabinoid rich extract from a hemp plant material, especially for the production of a hemp extract which is a botanical drug substance.

Preferably the extraction of CO2 is carried out at a temperature between 8-12 ° C, most preferably at a temperature of about 10 ° C.

Preferably the extraction of CO2 is carried out at a pressure between 55-65 bar, most preferably at a pressure of specifically 60 bar.

Most preferably, CO2 has a mass flow rate of from 1000-1500 Kg / hr, more preferably a mass flow rate of specifically 1250 Kg / hr.

Preferably, extraction with liquid CO2 is carried out for up to 10 hours, most preferably around 8 hours.

In a preferred embodiment, liquid CO2 is removed by unsealing and the resulting extract is kept at a temperature ranging from -15 ° C to -20 ° C.

Essentially any treatment that results in the selective removal of undesirable components (as opposed to cannabinoids) in the botanical drug substance can be any treatment such that the amount of undesirable components present in the final botanical drug substance is reduced. . Non-target materials are any material derived from a plant starting material that is not desired to be present in the final botanical drug substance. In a preferred embodiment of the invention, this step may include a C1-C5 alcohol precipitation, wherein the material treated in the alcohol precipitation step is warmed to a temperature greater than room temperature prior to the addition of the C1-C5 alcohol. Typically, the step to reduce the proportion of non-target materials in the botanical drug substance is carried out after extraction with liquid CO2, in which case the material to be treated with alcohol precipitation is the extraction product of liquid CO2. This extract is itself a botanical drug substance within the definition given above.

Preferably, the C1-C5 alcohol is ethanol. Preferably the extract is heated to a temperature ranging from 36 ° C to 44 ° C, most preferably around 40 ° C. Heating the treated material prior to the addition of the C1-C5 alcohol results in an improved mixing of the material with the C1-C5 alcohol and thus improves the efficiency of the alcohol precipitation step.

Preferably, the C1-C5 alcohol is added in an amount of from 3: 1 to 1: 1 volume of C1-C5 alcohol based on the weight of the treated material, more preferably in an amount of about 2: 1 volume of C1-C5 alcohol based on the weight of the treated material.

The solution formed by adding C1-C5 alcohol to the treated material is cooled and the insoluble materials are allowed to precipitate. Preferably the solution is cooled to a temperature ranging from -15 ° C to -25 ° C and preferably the solution is cooled over up to 52 hours.

The precipitate of the insoluble materials is then removed, usually by filtration. Preferably the filtration is performed through a 20 gm membrane.

PL 226 646 B1

The method may further comprise a multi-step evaporation under reduced pressure. This may be rotary evaporation or other known techniques.

Typically, the product of the C1-C5 alcohol precipitation step is subjected to a multi-stage evaporation to remove virtually all of the C1-C5 alcohol and water. Preferably, C1-C5 alcohol is removed first, followed by water.

Preferably, the C1-C5 alcohol is removed by heating to a temperature in the range of 58 ° C to 62 ° C to obtain a vapor temperature in the range of 38 ° C to 42 ° C, under a vacuum of 168-172 mbar, until the condensate is it was in a small amount or it will not be visible.

The water is then further removed, preferably by multi-stage reduction of the vacuum gradually to about 50 mbar.

The decarboxylation step can be performed before or after extraction with liquid CO2.

The decarboxylation step is carried out prior to liquid CO2 extraction and is accomplished by heating the plant material to temperatures and for periods of time that ensure at least 95% conversion of the acidic cannabinoids to their neutral form, ensuring that the thermal degradation of THC to CBN is less than 10% .

The decarboxylation of the cannabinoid acids is time and temperature dependent, so a shorter period of time will be used to completely decarboxylate a given amount of cannabinoid acid at higher temperatures. In selecting the appropriate decarboxylation conditions, however, consideration should be given to minimizing the thermal degradation of the desired pharmacological cannabinoids to undesirable degradation products, particularly the thermal degradation of THC to cannabinol (CBN).

Preferably the decarboxylation is carried out in a multistage heating process in which:

i) the plant material is heated to a first temperature over a first (relatively short) period of time to evaporate any absorbed water and allow the plant material to be evenly heated; and ii) the temperature is increased to a second temperature for a second period of time (typically longer than the first period of time ) until at least 95% of the acidic cannabinoids are converted to their neutral form.

Preferably the first step is carried out at a temperature in the range 100 ° C to 110 ° C for 10-20 minutes. More preferably, the first temperature is about 105 ° C and the first period of time is about 15 minutes.

When the plant material is derived from hemp plants with high CBD content (defined as> 90% CBD as a percentage of the total cannabinoid content), preferably the second temperature is in the range of 115 ° C to 125 ° C, preferably about 120 ° C. C and the second period of time is in the range of 45 to 75 minutes, preferably about 60 minutes. More preferably the second temperature is in the range of 135 ° C to 145 ° C, preferably about 140 ° C, and the second time period is in the range of 15 to 45 minutes, preferably about 30 minutes. For a weight of the plant material greater than 4 kg, the second temperature is in the range of 140 ° C to 150 ° C, preferably about 145 ° C, and the second period of time is in the range of 55-90 minutes. The latter conditions are favorable for processed amounts of, for example, 4-6 kg of starting plant material, and the exact numerical values, especially the time period, may slightly vary with increasing weight.

If the plant material is derived from cannabis plants with a high THC content (defined as> 90% THC as a percentage of the total cannabinoid content), preferably the second temperature is between 115 ° C and 125 ° C, typically around 120 ° C. C, and preferably the second period of time is in the range of 45 to 75 minutes, typically about 60 minutes. More preferably, the second temperature is in the range of 100 ° C to 110 ° C, preferably about 105 ° C, and the second period of time is in the range of 60 to 120 minutes, preferably about 30 minutes. In another embodiment, most preferred for a weight of the plant material greater than 4 kg, the second temperature is in the range of 140 ° C to 150 ° C, preferably about 145 ° C, and the second time period is in the range of 45 to 55 minutes. .

Most preferably, the decarboxylation step is performed at temperatures and for periods of time that ensure at least 97% conversion of the acidic cannabinoids to their neutral form, ensuring that the thermal degradation of THC to CBN is less than 5%.

Standard conditions for cannabinoid determinations and methods of calculating the cannabinoid content (in%) are given in the attached examples.

PL 226 646 B1

Preferably, the plant material used as the starting material in the extraction process is comminuted, ground or otherwise processed to obtain a particle size of less than 2 mm, but preferably greater than 1 mm. Such treatment usually results in a better extraction of cannabinoids from the plant material as the packing density is improved.

In a preferred embodiment, the extraction method may further comprise the step of treating an extract (or botanical drug material material) derived from the plant material with activated charcoal.

Typically, this step will be applied to the C1-C5 alcohol precipitation product, usually immediately after filtering to remove any precipitate. The liquid product of alcoholic precipitation is classified as a botanical drug substance according to the definition given above. The treatment with activated charcoal may conveniently be carried out by passing the liquid material to be treated down the column of activated charcoal.

As illustrated in the attached examples, the treatment with activated charcoal significantly improves the stability of the botanical drug substances derived from the hemp plant material, significantly improving the resistance to thermal degradation of the active cannabinoids.

In a preferred embodiment, the method will comprise the following steps for treating the hemp plant material, preferably in the order given:

i) decarboxylation, ii) extraction with liquid CO2 to produce the crude botanical drug substance, iii) C1-C5 alcohol precipitation to reduce the proportion of non-target materials, iv) filtering to remove precipitate,

v) evaporation to remove C1-C5 alcohol and water to produce the final botanical drug substance (BDS).

An activated charcoal treatment step may be included between step iv) and step v), which improves the stability of the final BDS.

The Applicant has further found that adding an aliquot of a modifying agent or a polar solvent to the liquid carbon dioxide solvent, for example a C1 to C5 alcohol, for example ethanol, can further increase the selectivity of the extraction method.

Another method of extracting cannabinoids from plant material involves extraction with liquid CO2, characterized in that an organic modifying agent or a polar solvent is added to carbon dioxide.

Preferably, the modifying agent or polar solvent is added in an amount of up to 10% by weight.

Preferably the modifying agent is a C1-C5 alcohol, most preferably ethanol.

Thus, the invention provides a botanical drug substance that can be obtained from a botanical raw material of a high-THC hemp plant having a THC content of at least 90% w / w relative to the total cannabinoid content, the above-mentioned botanical drug substance being an extract derived from a plant hemp with high THC content containing at least 50% THC w / w in relation to the extract, not more than 5% CBD w / w in relation to the THC content and not more than 5% of cannabinoids other than THC and CBD in% w / w in relation to the THC content.

More preferably the THC percentage of the w / w extract is at least 55%, even more preferably at least 60%. Other cannabinoids and quantification methods are given below.

The invention also provides a botanical drug substance that can be obtained from a botanical raw material of a high-CBD hemp plant having a CBD content of at least 90% w / w in relation to the total cannabinoid content, the above-mentioned botanical drug substance being an extract derived from the hemp plant with a high content of CBD, which extract contains at least 50% CBD w / w in relation to the extract, not more than 7.5% THC w / w in relation to the CBD content and not more than 5% of cannabinoids other than CBD and THC expressed in% w / w in relation to the CBD content.

It is known that plants with a high THC content, such as, for example, Skunk, have been grown, albeit with the intention of being used as recreational drugs, using traditional cultivation techniques that can also be used to produce plants rich in other cannabinoids, such as CBD. , using natural selection or genetic techniques since ge8

PL 226 646 B1 for cannabidiolate synthase and THC synthase, see JP 2001029082 and JP 2000078979.

Turkey CPRO 921018 is an example of a plant with a high CBD content.

The botanical drug substances can be obtained from hemp plant material (botanical raw material) using the extraction method of the invention.

In a preferred embodiment of the invention, the botanical drug substance contains no more than 4 ppb aflatoxin.

In a further preferred embodiment of the invention, the botanical drug substance contains no more than 20 ppm of total heavy metals.

In a further preferred embodiment of the invention, the botanical drug substance comprises no more than 15% w / w residual solvents, more specifically no more than 15% w / w ethanol.

In a further preferred embodiment of the invention, the botanical drug substance contains no more than 10⁵ cfu / g TVC (total indicator bacteria count), not more than 10⁴ cfu / g mushroom₃ bits, no more than 10³ cfu / g intestinal bacilli and other non-grammatical organisms and undetectable E. Coli, Salmonella or S. Aureus.

The parameters mentioned above relate to the botanical purity of the drug substance and define the purity level which is advantageous if the botanical drug substance is to be included in a pharmaceutical product. Botanical drug substances having the required level of purity can be obtained using the extraction method of the invention, particularly using the operating conditions and quality control procedures set forth in the accompanying examples. Standard assay techniques are known in the art for determining the levels of alphatoxin, heavy metals, residual solvents and bacterial contaminants in a botanical drug substance (e.g. standard Ph.Eur procedures). Additional details are provided in the accompanying Examples.

The botanical drug substances obtained from the hemp plant material according to the methods of the invention can be formulated with one or more pharmaceutically acceptable carriers, diluents or excipients or deposited on a pharmaceutically acceptable evaporation surface for the preparation of pharmaceutical preparations containing cannabinoids as pharmaceutically active agents.

Thus, in a further aspect, there is provided a process for the preparation of a pharmaceutical composition containing, as an active agent, a botanical drug substance which is an extract of at least one variety of hemp plants, which method comprises producing a botanical drug substance containing cannabinoids from at least one cannabis plant variety using the extraction method of the invention and formulating the botanical drug substance with one or more pharmaceutically acceptable diluents, carriers or vehicles or depositing the botanical drug substance onto a pharmaceutically acceptable evaporation surface for the manufacture of a pharmaceutical composition.

Separate botanical drug substances can be prepared from individual varieties of cannabis plants having different cannabinoid contents (e.g. high THC and high CBD) and then blended or blended together prior to formulation to form the final pharmaceutical composition. This approach is preferred if, for example, it is desired to achieve a specific weight ratio of the individual cannabinoids in the final formulation.

Alternatively, the botanical raw material of one or more cannabinoid varieties of a cannabis plant can be mixed together prior to extraction of one botanical drug substance having the desired cannabinoid content, which can then be formulated into the final pharmaceutical composition.

To prepare a pharmaceutical composition, the botanical drug substance may be formulated with any suitable pharmaceutically acceptable diluents, carriers or vehicles. The choice of diluents, carriers or excipients will depend on the dosage form desired, which in turn may depend on the intended route of administration to the patient. Preferred dosage forms include, inter alia, liquid dosage forms for administration by pump devices or aerosol sprays, tablets, lozenges, gels, capsules, suppositories, powders, etc. and vaporizers. Such dosage forms can be prepared according to standard pharmaceutical formulation known to those skilled in the art. Preferred dosage forms and methods for preparing such dosage forms are set out in the Applicant's International Application pending PCT / GB02 / 00620 (WO 02/064103).

Liquid preparations are particularly preferred. A particularly preferred formulation for the administration of cannabinoids, although not intended to limit the invention, is a liquid formulation

Containing the botanical drug substance, ethanol and propylene glycol, and optionally a flavoring agent, such as peppermint oil. This formulation may conveniently be administered to the buccal or sublingual mucosa by means of a pump spray. It ensures the effective absorption of active cannabinoids.

Furthermore, various aspects of the inventions are illustrated, by way of example only, with the following examples and the accompanying Charts.

Graph 1 shows the loss of THC over time at 40 ° C for the Reference THC-containing botanical drug substance (BDS) and charcoal-treated THC-containing BDS (purified BDS). Y axis: amount of THC (expressed as a percentage of t0 value), x axis: time in months.

Figure 2 shows the loss of CBD over time at 40 ° C for the Reference CBD-containing botanical drug substance (BDS) and the charcoal-treated CBD BDS (purified BDS). Y axis: amount of CBD (expressed as a percentage of the t0 value), x axis: time in months.

Graph 3 shows formation of cannabinol (CBN) over time at 40 ° C for Reference THC-containing botanical drug substance (BDS) and charcoal-treated THC-containing BDS (purified BDS). Y axis: amount of CBN (expressed as a percentage of t0 value), x axis: time in months.

Shortcuts

The generally accepted abbreviations for the main cannabinoids are as follows:

Tetrahydrocannabinol (THC), A.⁹-tetrahydrocannabinol (THC or A⁹-THC), A.⁸-tetrahydrocannabinol (A⁸-THC), the propyl equivalent of A.⁹-tetrahydrocannabinol (THCV), cannabidiol (CBD), cannabidiol propyl equivalent (CBDV), cannabiol (CBN), cannabichromene (CBC), cannabichromene propyl equivalent (CBCV) and cannabigerol (CBG).

Example 1 - Development of a method of extracting cannabinoids from hemp plants

A selection of chemical cannabis varieties

GW Pharma Ltd has developed distinct varieties of cannabis plant hybrids to maximize the yield of specific chemical components, cannabinoids. Two types of plant are used. One cannabis chemical primarily produces THC, and the other chemical hemp primarily produces CBD. However, alternative variations can be obtained - see, for example, the common cannabinoid phenotypes in 350 hemp raw materials, Smali and Beckstead, Lloydia, vol. 36b, 1973, pp. 144-156 and grown using techniques well known to one skilled in the art to maximize the cannabinoid content.

There are chemical and structural similarities between THC and CBD. Due to these similarities and because of the botanical origin of the starting materials, they can be considered interchangeable when developing methods to extract cannabinoids.

Preferably, each cannabis chemical is treated and controlled separately to obtain two different BDS. However, it is possible to mix plant material from two or more chemical varieties, or to use a variety that produces the desired ratio of given cannabinoids prior to extraction, thereby producing one BDS.

Production of botanical raw material

BDS is made from extracts of Cannabis sativa L. (Cannabidaceae family). Cannabis sativa was described in the British Pharmacopoeia 1934. Cannabis is grown under authorization from the UK Home Office, under the control of GW Pharma Ltd in the UK. The cultivation facilities are equipped with curtains and an air-conditioning unit with full control (temperature, humidity and high intensity lighting) so that it is possible to obtain several crops per year under almost identical conditions, ensuring continuity of supply.

Cultivation

Hemp plants are propagated from cuttings taken from parent plants obtained from a single hay source. Thus, plants are produced by asexual reproduction in which all plants are female. Propagation with cuttings regulates the consistency of the genotype.

The seedlings are planted in pesticide-free compost. During the growth cycle, the plants are watered and sustained-release fertilizer applied. Due to controlled growth conditions, the plants reach maturity in approximately 12 weeks.

The plants are irrigated with quality drinking water throughout the entire growth cycle.

No synthetic herbicides or pesticides are used in the cultivation of hemp plants.

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Compost

Effective cannabis cultivation requires a supply of absolutely homogeneous growth media.

Compost is characterized by a soft structure, high air permeability, easy wetting, low conductivity and a balanced supply of nutrients. The compost consists of peat and added natural minerals, including quicklime (magnesium and calcium carbonates), which ensure that the pH of the compost is regulated during the cannabis plant growth cycle.

Compost contains an adequate supply of essential minerals and a minimal amount of minerals with known harmful side effects on plants. Some manganese-containing minerals may be present in the compost in an insoluble form and may be additionally released in a readily soluble form. Controlling the pH of the compost and monitoring irrigation to avoid soil saturation with water will ensure control of soluble manganese levels. The pH of the compost is kept above 5.5. The compost contains no pesticides as no pesticides or herbicides are added.

Artificial fertilizer

Compost contains fertilizer identified in two distinct forms - base fertilizer and slow-release fertilizer. Additional slow release fertilizer is applied to the plants while they are growing.

Pest and disease control

No artificial herbicides or pesticides are used during cultivation. Harsh hygiene conditions will reduce pest access and disease incidence.

Controlling growing conditions, environmental stresses such as drought, insufficient light and unfavorable temperatures reduces the risk of disease.

Checking the plants regularly during the growth cycle can detect defective plants and pests. Defective male plants may appear, although weeds should be absent due to controlled growing conditions and the environment. Frequent checkups and biological control methods are used to control any pests and diseases that may arise.

Collection of plants

Thanks to strict control of growing conditions, cannabis plants reach maturity in approximately 12 weeks. Compact resinous flowers develop in the last weeks of growth. By the end of approximately week 11, cannabinoid biosynthesis is noticeably slowing down and the plants are ready for harvest.

The whole plant is cut and dried in a temperature and humidity controlled environment:

- approximately 21 ° C

- approximately 38-45% RH.

The dry plant is physically assessed at the endpoint. THC and CBD are the primary bioactive ingredients in BDS. However, these components are present in BRM as biologically inactive carboxylic acids:

- THCA

- CBDA

The acid forms are slowly decarboxylated during drying over time. Leaves and flowers are removed from larger stems to obtain Botanical Raw Material (BRM).

Storage of BRM

Under storage conditions, the loss on drying reaches an equilibrium of approximately 10%. The conditions for dry storage of BRM will depend on the physical condition of BRM.

Normal storage conditions for BRM

- protected against light

- approximately 15-25 ° C or -20 ° C

- approximately 38-45% RH

Producing BRM at a glance

Collection of plants

Drying (without light)

BRM (contains THCA + CBDA)

PL 226 646 B1

Milling to reduce the particle size to less than 2000 µm

Decarboxylation of the acid form of cannabinoids (THCA + CBDA) to produce neutral cannabinoids (THC + CBD)

A description of a typical BRM from a high-CBD cultivar is illustrated in Table 2.

Table 2

<td>Research</td><td>Method</td><td>Description</td>

<td>- A - B - C.</td><td>Visual TLC HPLC / UV</td><td>It is correct Conforms to the standard (for CBD and CBDA) Positive for CBDA</td>

<td>Mark CBDA + CBD</td><td>Inside (HPLC / UV)</td><td>Not less than 90% of cannabinoids determined by peak area</td>

<td>Loss on drying</td><td>Ph.Eur.</td><td>Not more than 15%</td>

<td>Aflacosin *</td><td>UKAS method</td><td>Not more than 4 ppb</td>

<td>Microbiological: ** - TVC - Mushrooms - E. Coli</td><td>Ph.Eur.</td><td>No more than 10⁷cfg / g No more than 10⁵ cfg / g No more than 10² cfg / g</td>

<td>Foreign body</td><td>Ph.Eur.</td><td>Not more than 2%</td>

<td>Residual herbicides and pesticides ***</td><td>Ph.Eur.</td><td>It is correct</td>

Analytical methods

Visual identification

The macroscopic properties make it possible to distinguish the characteristics of the cannabis plant from possible adulteration substances and substitutes. It is a visual identification in relation to the photographic pattern.

Identification by TLC

Both the retention time and the characteristic color of the spots are used to successfully identify a cannabis variety by means of TLC. For TLC analysis, laboratory samples are prepared by extracting the dry herb. Aliquots are spotted on a TLC plate alongside reference samples for THC and CBD. When exposed to Fast Blue B reagent, THC and THCA appear as pink patches, while CBD and CBDA are orange in color. Neutral compounds can be distinguished from acids by comparing the Rf values ​​with the value obtained for the standards. Identification is confirmed by comparing the Rf and color of the sample spot with the value obtained for the appropriate standard.

Identification by HPLC

A comparison of cannabinoid retention times is used to efficiently identify a cannabis strain by HPLC.

A specific method for CBD and CBDA is reverse phase HPLC and therefore can be used as an identification test. The biomass samples are extracted and centrifuged. Detection of all analytes is made at 220 nm with additional confirmation of the acid analytes at 310 nm.

Determination (CBD + CBDA)

This assay is used to monitor the CBD and CBDA content of the plant. The assay of CBD and CBDA is determined using the HPLC method.

The efficiency of the decarboxylation process is determined by dividing the% w / w CBD content by the total CBD + CBDA content.

Loss on drying

Loss on drying is assessed using the Ph.Eur measurement method.

PL 226 646 B1

Aflatoxin

Aflatoxin is analyzed using a method accredited by the UK Accreditation Authority (UKAS).

Microbiological examination

Microbiologically, the plant is assessed using the Ph.Eur methodology.

Foreign body

The foreign body is assessed using the Ph.Eur measurement method. Flowers, leaves and side stems are spread out as a thin layer on a clean laboratory surface. The foreign body is separated by hand as best as possible and weighed. The results are expressed in% w / w foreign body in the herbal biomass sample. The foreign body may constitute no more than 2% of the biomass.

Residual herbicides and pesticides

Hemp plants grow in a well-controlled environment. No artificial herbicides or pesticides are used, or are not necessary during cultivation.

For a high THC-rich variety, a BRM equivalent description is generated (cf. Table 2) and identical analytical methods are used, except that THC / THCA replaces

CBD / CBDA.

Decarboxylation

THC and CBD are the primary bioactive ingredients in cannabis. However, these ingredients are present in cannabis plants as biologically inactive carboxylic acids. In order to extract THC or CBD from hemp plant material, it is necessary to convert the stored THCA and CBDA precursor compounds into easily extractable and pharmacologically active forms. In their natural state, THC and CBD are slowly decarboxylated. The conventional way to increase the rate of decarboxylation is to apply heat. However, THCA is converted not only into THC but also into another cannabinoid, cannabinol (CBN).

°

THCA or CBDA (C22H30O4) THC or CBD (C21H30O2)

The decarboxylation procedure is usually done as part of the preparation of the starting material or botanical raw material (BRM) before starting the extraction process.

Laboratory studies - decarboxylation

Portions of the ground dry plant material were subjected to heat (approximately 0.25 g of particle size 1-2 mm). An experimental pilot-scale system was set up to determine the parameters for the optimal conversion of THCA or CBDA to THC and CBD, respectively, with coexisting minimal loss of these resulting compounds due to thermal degradation to thermal degradation products, in the case of THC this is the formation of CBN.

Brief description of materials and methods

Portions (0.25 g) of ground (approximately 1-2 nm particle size) herbal materials, both THCA and CBDA, were placed in 20 ml glass vials with headspace and the vials sealed with butyl rubber seals covered with Teflon with crimp cap. The closed vials were heated to one of three temperatures for periods of up to 4 hours as follows: 105 ° C, 120 ° C, 140 ° C for 0.5, 1.0, 2.0 and 4.0 hours.

Heating was carried out in a forced-air oven. The oven conditions were shown to be accurate to within 0.5-1.0 degrees at the three temperatures used.

After completion of the heating process, representative samples of the decarboxylated herb were assayed using HPLC, GC, and TLC techniques. Standards of THC, CBD and CBN are included in the HPLC and GC sequences.

Results and discussions

HPLC analysis of the solvent extracts showed disappearance of either CBDA or THCA depending on the time at the lower two temperatures. At 140 ° C, the samples at the earlier 0.5 hour time point contained only very small levels of peak elution at the retention times of CBDA or THCA.

Tables 3 and 4 present HPLC data quantifying the conversion of CBDA or THCA to free compounds. Data showing the content of CBD or THC and the ratio of CBD / CBDA + CBD or THC / THCA + THC are also provided. The conversion of the carboxylic acid form to the corresponding decarboxylated form can be monitored by comparing the ratio of decarboxylated / decarboxylated plus nondecarboxylated compounds to the total amount of compounds

PL 226 646 B1 are decarboxylated. Thus, when the ratio reaches its maximum value (> 0.95), the earlier time / temperature point at which the THC or CBD content is also maximum should be optimal for the conversion process.

So for a CBD herb, 1 hour at 120 ° C or 0.5 hour at 140 ° C was appropriate.

This is confirmed by examination of the TLC chromatogram for solvent extracts, CBDA is absent after 1 hour at 120 ° C or at any time point at 140 ° C.

For THC there is a third criterion, CBN formation, where it is desirable to minimize the formation of this compound during the thermal decarboxylation process. Table 5 shows the gas chromatography (GC) data from which a CBN / THC ratio can be obtained. Given both the THC / THCA + THC ratio and the maximum THC content, minimal CBN formation occurs after 0.5 hour or 1.0 hour at 120 ° C. At 140 ° C, even 0.5 hours gives a higher CBN content than either of the lower two time / temperature points.

Therefore, laboratory studies show optimal conditions for decarboxylation:

- Chemical variety that mainly produces CBD - 1 hour at 120 ° C or 0.5 hour at 140 ° C.

- Chemical variety that mainly produces THC to minimize CBN formation - 1 to 2 hours at 105 ° C or 1 hour at 120 ° C.

Thin layer chromatography shows that virtually all of the THCA is gone after 4 hours. at 105 ° C and after 1 hour at 140 ° C. THCA is not visible at any time point as the herb is heated to 140 ° C. A small amount of residual color at this TLC retention value and the presence at low levels of a peak convergent with THCA in HPLC analysis may indicate less cannabinoid presence than residual THCA.

Table 3

HPLC data from decarboxylation of CBDA herbal material

<td>Temperature</td><td>Time (hours)</td><td>CBD / CBD + CBDA</td><td>CBD peak area / 0.1 g herb</td>

<td rowspan="5">105 ° C</td><td>Zero</td><td> 0,15</td><td> 4769</td>

<td> 0,5</td><td> 0,22</td><td> 5262</td>

<td> 1,0</td><td> 0,86</td><td> 5598</td>

<td> 2,0</td><td> 0,93</td><td> 5251</td>

<td> 4,0</td><td> 0,98</td><td> 5242</td>

<td rowspan="4">120 ° C</td><td> 0,5</td><td> 0,91</td><td> 5129</td>

<td> 1,0</td><td> 0,97</td><td> 5217</td>

<td> 2,0</td><td> 0,99</td><td> 5037</td>

<td> 4,0</td><td> 1,00</td><td> 5200</td>

<td rowspan="4">140 ° C</td><td> 0,5</td><td> 0,96</td><td> 5440</td>

<td> 1,0</td><td> 1,00</td><td> 5105</td>

<td> 2,0</td><td> 1,00</td><td> 5157</td>

<td> 4,0</td><td> 1,00</td><td> 5005</td>

Table 4

HPLC data from decarboxylation of THCA herbal material

<td>Temperature</td><td>Time (hours)</td><td>THC / THC + THCA</td><td>THC peak area / 0.1 g herb</td>

<td> 1</td><td> 2</td><td> 3</td><td> 4</td>

<td rowspan="5">105 ° C</td><td>Zero</td><td> 0,17</td><td> 992,9</td>

<td> 0,5</td><td> 0,87</td><td> 5749</td>

<td> 1,0</td><td> 0,93</td><td> 5273</td>

<td> 2,0</td><td> 0,98</td><td> 7734</td>

<td> 4,0</td><td> 0,99</td><td> 7068</td>

PL 226 646 B1 cont. table 4

<td> 1</td><td> 2</td><td> 3</td><td> 4</td>

<td rowspan="4">120 ° C</td><td> 0,5</td><td> 0,97</td><td> 7189</td>

<td> 1,0</td><td> 0,99</td><td> 6391</td>

<td> 2,0</td><td> 0,99</td><td> 6500</td>

<td> 4,0</td><td> 1,00</td><td> 5870</td>

<td rowspan="4">140 ° C</td><td> 0,5</td><td> 1,00</td><td> 6724</td>

<td> 1,0</td><td> 1,00</td><td> 5981</td>

<td> 2,0</td><td> 1,00</td><td> 5361</td>

<td> 4,0</td><td> 1,00</td><td> 4787</td>

Table 5

GC data from decarboxylation of THC herbal material

<td>Temperature</td><td>Time (hours)</td><td>CBN / THC (%)</td>

<td rowspan="5">105 ° C</td><td>Zero</td><td> 2,4</td>

<td> 0,5</td><td> 3,5</td>

<td> 1,0</td><td> 4,2</td>

<td> 2,0</td><td> 3,7</td>

<td> 4,0</td><td> 5,6</td>

<td rowspan="4">120 ° C</td><td> 0,5</td><td> 3,2</td>

<td> 1,0</td><td> 4,1</td>

<td> 2,0</td><td> 6,7</td>

<td> 4,0</td><td> 11,3</td>

<td rowspan="4">140 ° C</td><td> 0,5</td><td> 5,7</td>

<td> 1,0</td><td> 13,00</td>

<td> 2,0</td><td> 17,5</td>

<td> 4,0</td><td> 23,8</td>

The decarboxylation conditions for a batch scale of about 4 kg of botanical raw material (BRM) are as follows.

Approximately 4 kg of the ground BRM (either THCA or CBDA) to be decarboxylated was preheated to 105 ° C and held at this temperature for about 15 minutes to evaporate any absorbed water and allow the BRM to be evenly heated. The batch was then further heated to 145 ° C and held at this temperature for approximately 45 minutes to allow decarboxylation to be completed with greater than 95% efficiency.

The heating time of BRM CBDA was increased to 55 minutes at 145 ° C as it was found from the results that CBDA was slightly more resistant to decarboxylation than THCA. In commercial scale batches, this difference between CBD and THC would be even more pronounced. The heating time for BRM THC was at 145 ° C 45 minutes.

The conditions used in the pilot scale closely reflect the conditions identified as optimal in the laboratory tests. The differences can be explained by the slower and less efficient heat transfer through the tanks and by the BRM with the larger batch size for the pilot scale.

Tables 6 and 7 present the data to demonstrate the efficiency of decarboxylation as measured by the levels of biologically active cannabinoid, THC or CBD.

PL 226 646 B1

Table 6

Decarboxylation efficiency for BRM CBD

<td>CBD batch number</td><td>% Decarboxylation Efficiency specification&gt; 95%</td>

<td>AND</td><td> 98,8</td>

<td>B</td><td> 99,5</td>

<td>C.</td><td> 98,3</td>

<td>D</td><td> 100,0</td>

<td>E.</td><td> 100,0</td>

<td>F.</td><td> 100</td>

<td>G.</td><td> 96,9</td>

<td>H.</td><td> 100,0</td>

An increase in the batch size of BRM CBD from approximately 4 kg to 6 kg necessitated an increase in the decarboxylation time. The decarboxylation time at 145 ° C was increased from 45 minutes to 90 minutes.

Table 7

<td>THC batch number</td><td>% Decarboxylation Efficiency Specification&gt; 95%</td>

<td>AND</td><td> 98,4</td>

<td>J.</td><td> 97,3</td>

<td>K.</td><td> 98,5</td>

<td>L.</td><td> 100,0</td>

<td>M.</td><td> 97,8</td>

<td>N</td><td> 99,9</td>

<td>ABOUT</td><td> 100,0</td>

Summary of the extraction method

BDS is extracted from decarboxylated BRM using the liquid carbon dioxide method. This is done by continuously passing liquid carbon dioxide through the chopped biomass, which is contained in a high-pressure tank. The crude extract is dissolved in ethanol, cooled to low temperature, then filtered to remove precipitated components such as waxes. Removal of ethanol and water in vacuo gives BDS containing high concentrations, depending on the biomass used, either CBD or THC.

Technological scheme of a typical extraction method

BRM is decarboxylated by heating to approximately 105 ° C for 15 minutes, then to approximately 145 ° C for a minimum of 55 minutes for THCA and 90 minutes for CBDA and

Extraction with liquid carbon dioxide (CO2) [food grade] for up to 10 hours

Conditions: pressure of approximately 60 bar ± 10 bar and 10 ° C ± 5 ° C and

Removal of CO2 by unsealing to obtain a crude extract ^and

De-stearing - Dissolving the crude extract in ethanol followed by cooling the solution (-20 ° C ± 5 ° C / up to 52 hours) to precipitate unwanted waxes and

Removal of unwanted wax material by cold filtering (20 nm filter) ^and

Removal of ethanol and water from the filtrate by thin film evaporation under reduced pressure (60 ° C ± 2 ° C, with steam at 40 ° C ± 2 ° C / 172 mbar and 72 mbar + 4 mbar) ^and

BDS (Stored at -20 ° C ± 5 ° C)

PL 226 646 B1

Extraction # 1

The first phase of the manufacturing process is extraction with liquid CO2 under subcritical conditions.

Experiments have shown that both THC and CBD could be extracted from hemp plant material with high efficiency using subcritical CO2, at a low temperature of approximately 10 ± 5 ° C, using a pressure of approximately 60 bar ± 10 bar.

Table 8 below shows the comparative data obtained with THC rich BDS.

Table 8

<td>No cargo</td><td>Pressure Bar</td><td>Temperature ° C</td><td>% w / w wax removed</td><td>% THC w / w after de-stearing</td>

<td>Ac1202</td><td> 400</td><td> 60</td><td> 8,2</td><td> 67,2</td>

<td>Ac1205</td><td> 400</td><td> 60</td><td> 6,1</td><td> 67,0</td>

<td>Ac1206</td><td> 400</td><td> 60</td><td> 6,1</td><td> 68,0</td>

<td>Three series</td><td> 60</td><td> 10</td><td> 2,2-4,8</td><td> 59,9-73,7</td>

<td></td><td></td><td></td><td>Wed about 3</td><td>Wed 65%</td>

From the results it can be concluded that there is a loss of selectivity as indicated by the high weight of the wax under supercritical conditions. Although larger amounts of wax can be removed by de-stearing, processing is difficult because, for example, filters are blocked.

Similar results were obtained with CBD.

The preferred extraction conditions with liquid CO2 are as follows:

The decarboxylated botanical raw material is packed in a single column and exposed to liquid CO2 under pressure.

- Batch size: approximately 60 kg

- Pressure: 60 bar ± 10 bar

- Temperature: 10 ° C ± 5 ° C

- Time: approximately 8 hours

- CO2 mass flow 1250 kg / h + 20%.

The preferred parameters of the BDS production method are as follows: extraction time> 10 hours, CO2 pressure 50-70 bar, extraction temperature 5-15 ° C, CO2 mass 167 kg / kg BRM.

After unsealing and removal of CO2, the crude BDS extract is collected in closed tanks. Primary BRM is reduced to approximately 10% w / w crude BDS extract. The crude BDS extract is stored at -20 ° C ± 5 ° C.

Raw BDS extract contains waxes and long-chain molecules. Their removal is accomplished by a de-stearinization procedure (extraction 2) which allows the crude BDS extract to be heated to eg 40 ° C ± 4 ° C in order to liquefy the material. Ethanol is added in a ratio of 2: 1 ethanol volume to the weight of the crude BDS extract. The ethanol solution is then cooled to -20 ° C 5 ° C and held at this temperature for approximately 48 hours.

After completion of stearinization, the precipitate formed is removed by cold filtering through a 20 µm filter.

Extraction number 2

The second step in the manufacturing process is Extraction No. 2, referred to as "ethanol de-stearation". Crude BDS extract is made from Extraction No. 1 and contains ingredients such as waxes. Ethanol efficiently extracts long-chain molecules from the crude extract.

Research

It was found that by heating the crude BDS extract to approximately 40 ° C the miscibility of the crude extract with the solvent was improved.

It was preferable to cool the stearinating solution to -20 ° C in about 48 hours.

The preferred parameters for the BDS production process are as follows: extraction temperature 36-44 ° C, ethanol: product ratio approximately 2: 1, freezer temperature -25 ° C to -15 ° C, time 48-54 hours.

PL 226 646 B1

Filtration

The ethanolic solution produced in the second extraction phase requires filtration to remove the precipitate formed. Preferably the size of the filter is 20 gm.

The preferred parameters of the BDS production method are as follows: total filter time> 6 hours.

Evaporation

The final step of the manufacturing process is to remove any ethanol and water that may be present. Preferably it is carried out by heating at 60 ° C 2 ° C to obtain a vapor temperature of 40 ° C 2 ° C under a vacuum of 172 mbar 4 mbar. The distillation is continued under these conditions until there is little or no visible condensate. By lowering the vacuum further, the removal of water is completed gradually to approximately 50 mbar. Upon completion of BDS, it is transferred to closed stainless steel containers and stored in a freezer at 20 ° C ± 5 ° C.

The preferred parameters of the BDS production process are as follows: temperature of evaporating steam 38-42 ° C, removal of ethanol in vacuo 167-177 mbar, removal of water in vacuo 70-75 mbar 62-58 mbar 52-48 mbar, time &lt;8 hours.

Characteristics of BDS

BDS containing THC is a brown, sticky, semi-solid extract containing at least 60% cannabinoid ingredients. The cannabinoid ingredients contain at least 90% THC, approximately 1.5% CBD with the remainder consisting of other secondary cannabinoids.

The chemical composition of cannabis has been studied extensively with the identification of more than 400 compounds [Hendricksi et al., 1975, Turner et al., 1980). More than 60 cannabinoids have been identified, with CBDA and THCA (the precursors to CBD and THC) being the most abundant. Typically, the non-cannabinoid constituents constitute up to 50% of the extracts, depending on the extraction method. The identified chemical categories include alkanes (chains with 25-30 carbon atoms), nitrogen compounds, amino acids, sugars, aldehydes, alcohols and ketones, flavanoids, glycosides, vitamins, pigments and terpenes. About 95 mono- and sesquiterpenes have been identified in cannabis and are responsible for the characteristic smell.

Considerable work has been done to completely elucidate the structure of both CBD and THC (summarized in the materials above) and both have been made synthetically. Pure THC was successfully isolated in sufficient quantity from BDS to be used as reference material for identification and quantification.

pollution

BDS is a selective extract from the dry, decarboxylated leaves and flowering crowns of certain chemical hemp varieties. A range of over 400 compounds have been found in cannabis plants, including over 60 cannabinoids (Turner 1980). As they occur in nature, it is not considered necessary to treat any of these compounds as contaminants. The main contaminants therefore emerge in four areas: pesticides introduced during the growth process, alphatoxins, any new products formed by decarboxylation, and non-cannabinoid materials that constitute BDS.

The growth process is strictly controlled using the guidelines of Good Agricultural Practice and takes place in a growing environment in a closed room with a controlled climate. No pesticides are applied to the plants during growth, and all pest control is carried out with biological agents. No pesticides are introduced into the growing environment. To ensure that no pesticide residues are present in the product, the growth environment is periodically tested for pesticides known to be used by the supplier of the growth medium.

After the plant material has been harvested and dried, additional samples are periodically tested using a common pesticide screen to ensure that no contamination of the plant has occurred. Possible pesticides are adequately controlled in the BRM phase.

The raw material may be microbiologically contaminated, resulting in alpha toxins in the product, although growth conditions are carefully controlled to prevent this from happening. Therefore, the BRMi BDS is tested periodically for alphatoxin content.

The form of THC found naturally in a freshly grown plant is acidic THCA, although small amounts of neutral THC are present. Prior to extraction, the THCA is decarboxylated by heating to obtain neutral THC. The method works, but a small amount of THCA remains, and that's it

PL 226 646 B1 monitored during the final BDS study. Thermal degradation of THCA and THC during the decarboxylation process is possible and gives CBNA and CBN. They are monitored in the BDS.

The non-cannabinoid ingredients that are ballast of the BDS include hydrocarbon and triglyceride waxes, plant pigments, and terpenes. They are common to many other medicinal plant extracts and are considered to be of little toxicological and pharmacological importance. The variety of other ingredients present is wide, but they are usually only present in small amounts.

The amount of ballast is reduced by the de-stearing process in which the waxes are precipitated. Ballast materials are considered to be a solvent for the active ingredients and are not marked or controlled.

Table 9

Specification for the control of BDS high in CBD

<td>Research</td><td>Method measuring</td><td>Limit values</td>

<td>Look</td><td>Inside</td><td>Brown, sticky, semi-solid</td>

<td>Identification</td><td>TLC</td><td>The stains have characteristic Rf and colors,</td>

<td>- A</td><td>HPLC / UV</td><td>compared to the CBD standard</td>

<td>- B</td><td></td><td>Positive for CBD</td>

<td>CBD content</td><td>Inside (HPLC-UV)</td><td>Not less than 55% w / w extract</td>

<td>Related cannabinoids</td><td>Inside</td><td>Not more than 7.5% of the CBD content</td>

<td>- THC content - other (total)</td><td>(HPLC-UV)</td><td>Not more than 5% CBD content</td>

<td>Aflatoxin *</td><td>TBA</td><td>Not more than 4 ppb</td>

<td>Total heavy metal content</td><td>Ph.Eur.</td><td>Not more than 20 ppm</td>

<td>Residual solvents: - Ethanol</td><td>Inside</td><td>Not more than 5% w / w</td>

<td>Microbiological: ***</td><td>Ph.Eur.</td><td>No more than 10⁵ cfg / g</td>

<td>- TVC</td><td></td><td>No more than 10⁴ cfg / g</td>

<td>- Mushrooms - Other intestinal sticks and certain other non-negative organisms</td><td></td><td>No more than 10³ cfg / g</td>

<td>- E. Coli</td><td></td><td>Absent in 1 h</td>

<td>- Salmonella</td><td></td><td>Absent in 10 g</td>

<td>- S. aureus</td><td></td><td>Absent in 1 h</td>

Analytical procedures

Identification, labeling, and related cannabinoids

The content of THC, CBD and cannabinol (CBN) in BFM and BDS is quantified by extraction with methanol or methanol / HP with chloroform (9: 1). The method of quantification is reversed-phase high-performance thin layer chromatography (HPLC) with UV-220 nm detection. Any analysis should be performed under amber light as the compounds of interest are known to be photosensitive.

Chromatographic equipment and conditions

Equipment

HPLC column

Introductory column

Mobile phase

Agilent (HP) 1100 HPLC system with variable wavelength UV detector or Diode-Array Discovery C8 detector 5 pm 15 cm x 0.46 cm Kingsorb C18 5 pm 3 cm x 0.46 cm

Acetonitrile: Methanol: 0.25% w / v acetic acid (16: 7: 6 by volume)

Temp. columns

25 ° C

PL 226 646 B1

Flow rate Detection

Volume injected Transition time

Sequence of elution

1.0 ml min^-1

220 nm 600 mA maximum scale excursion - Second wavelength 310 nm 10 gm

20-25 minutes (may extend to low-volume samples with peaks later eluting)

BD, CBDA, Δ⁹ THCV, CBN, Δ⁹ THC, CBC, Δ⁹ THCA

Generation of the pattern

-1

CBD, CBN, Δ stock standard solutions⁹ THC in methanol approximately 1 mg 1 ml^-1stored at -20 ° C.

Diluted working standards (0.1 mg / ml for Δ⁹ THC and CBD and 0.01 mg / ml for CBN) are prepared in methanol from stock standards and stored at -20 ° C (maximum period of twelve months after initial production). After preparation, stock solutions should be divided into vials of equal volumes to reduce the amount of standard exposed to room temperature. Prior to sample analysis by HPLC, the required number of standard vials are removed and allowed to equilibrate at room temperature.

Production of samples

Alternate weights and volumes can be used in all preparations to achieve the same final dilutions.

Botanical raw material

- Accurately weigh approximately 100 mg of cut homogeneous dry material and place in a 10 ml volumetric flask.

- Diffuse material in methanol / chloroform (9: 1 v / v) and make up to volume with the same solvent.

- Extract the sample in an ultrasonic bath within 15 minutes.

- Centrifuge samples containing equal volumes of 3000 rpm for approximately 2 minutes.

- Dilute 100 gm of supernatant to 1 ml with methanol in a suitable HPLC sample vial. (Further dilution may be required if the main cannabinoid concentration is outside the linear operating range).

Decarboxylated Botanical Raw Material:

As with the botanical raw material

Botanical drug substance

- Accurately weigh approximately 80 mg of BDS and place in a 50 ml volumetric flask.

- Dissolve BDS and make up to volume with methanol.

- Dilute 100 gm of the prepared supernatant to 1 ml with methanol in a suitable HPLC autosampler vial.

Chromatographic procedure

The samples are placed on the autosampler rack for listing at the Agilent chemstation. Standard solutions are used to obtain quantitative data and retention times. They can typically be injected two or three times before injecting the sample solutions, and then singly at appropriate intervals throughout the run, with a maximum of 10 test samples between standards.

Chromatographic eligibility criteria

Table 10

Retention times and relative retention times (RRT) values ​​versus Δ⁹ THC for each analyte

<td>Cannabinoid</td><td>Retention time (minutes)</td><td>RRT (THC)</td>

<td> 1</td><td> 2</td><td> 3</td>

<td>CBD</td><td> 5,1-5,8</td><td> 0,58</td>

<td>CBN</td><td> 7,4-8,3</td><td> 0,83</td>

PL 226 646 B1 cont. table 10

<td> 1</td><td> 2</td><td> 3</td>

<td>Δ⁹ THC</td><td> 9,0-10,0</td><td> 1,00</td>

<td>CBDA</td><td> 5,5-6,2</td><td> 0,615</td>

<td>Δ⁹ THCV</td><td> 5,9-6,6</td><td> 0,645</td>

<td>CBC</td><td> 11,6-12,8</td><td> 1,30</td>

<td>Δ⁹ THCA</td><td> 14,6-16,0</td><td> 1,605</td>

Table 11

Peak shape (symmetry coefficient according to the British Pharmacopoeia method)

<td>Cannabinoid</td><td>Symmetry Factor</td>

<td>CBD</td><td> &lt; 1,30</td>

<td>CBN</td><td> &lt; 1,25</td>

<td>Δ⁹ THC</td><td> &lt; 1,35</td>

Calculation

Botanical raw material

The following equation is used to obtain a result on the purity of the main cannabinoid as% of the cannabinoids currently measured (CBD, CBDA, CBN, Δ⁹ THC and Δ⁹ THCA) in a lot.

For materials with a high Δ content⁹ THC:

sum of THC and THCA peak areas sum of the peak areas of the determined cannabinoids

For material with high CBD content, CBD and CBDA replace THC and THCA in the top line of the equation.

Decarboxylated botanical raw material

The following equation is used to calculate the efficiency of the decarboxylation process:

For materials with a high Δ content⁹ THC:

% decarboxylation yield THC peak area sum of THC and THCA peak areas x100

For material with high CBD content, CBD and CBDA replace THC and THCA in the equation.

Botanical drug substance

The following equations are used to calculate the concentration of a sample drug substance, the concentration of cannabinoids in an individual sample, the percentage of assayed cannabinoids in the drug substance, the amount of the main cannabinoid as% of the currently assayed cannabinoids, and the amount of the main cannabinoid in the total weight of the extracted drug substance.

For material with high Δ content⁹ THC:

sample weight

Sample concentration of drug substance = ------ dilution factor where dilution factor = 50 x 10 = 500

THC concentration of sample conc, standard x avg. over THC samples average surface area of ​​the THC standard% w / w contained THC Drug Substance = Sample Concentration THC Sample Concentration of Drug Substance

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CBD and CBN can be substituted for all of these equations in place of Δ⁹ THC to obtain quantitative results for both substances. Δ⁹ THCA and CBDA are also calculated using the standard concentrations for Δ⁹ THC or CBD in the absence of its own specific reference standards.

The substances concerned are defined as the sum of the mean% w / w CBN values, Δ⁹ THC and CBDA.

THC as% of the total measured cannabinoids% w / w. THC sum% in all cannabinoids assayed

The total amount of Δ is obtained⁹ THC present in the entire drug substance extract.

Example 2 - Analysis of the stabilization of the botanical drug substance (BDS) by partial purification with activated charcoal

Results from stability studies of THC preparations show that THC in the form of BDS is unstable even at storage temperatures as low as 5 ° C. This contrasts with the behavior of purified THC (Dronabinol USP) in Marinol soft gel capsules, for which a shelf life of 2 years at fairly low ambient temperatures is assumed. It should also be noted that the shelf life of THC standard solutions in methanol supplied by Sigma-Aldrich is 4 years when stored chilled and protected from light.

This apparent discrepancy between BDS (THC) stability and purified THC led to speculation that a certain component of BDS destabilized the main cannabinoid.

The solution to this problem would be to purify the BDS (THC) to obtain high purity, preferably crystalline cannabinoid. However, the additional processing costs associated with converting BDS into pure cannabinoid would significantly increase the cost of finished cannabinoid-containing pharmaceutical products.

Accordingly, the applicant has attempted to develop a simple purification step that would produce BDS with greater stability, but which would not unduly increase processing costs.

The Applicant has found that the charcoal purification step can conveniently be carried out in close conjunction with a de-stearinating process by passing the stearinized ethanol solution in one step through a filter layer to remove precipitated waxes and then directly through a charcoal column, and that the use of activated charcoal significantly improves storage.

Experimental details

Solutions of either BDS (THC) or BDS (CBD) at a concentration of 100 mg / ml in absolute ethanol BP were passed through a column packed with activated charcoal and the eluate was collected. They were then diluted with additional absolute ethanol to achieve a concentration of approximately 25 mg / ml of cannabinoid. The solution was then transferred to a 10 ml AX1 type vial (ie amber glass) and the clamp was closed. These samples were referred to as charcoal purified BDS.

Samples of the BDS (THC) and BDS (CBD) solutions that were not passed through the charcoal column were similarly diluted to provide a cannabinoid concentration of 25 mg / mL and then sealed in an amber glass vial of the same type. These samples were designated as the reference BDS and served as stability controls.

Vials containing the standard BDS and charcoal purified BDS of each type were stored in a stability incubator at 40 ° C and samples were then periodically removed for 1-12 months for cannabinoid analysis by HPLC and profile determination by TLC.

The following conditions were used in the normal phase TLC analysis:

Stationary phase silica gel G

Mobile phase 80: 20 hexane / acetone

Unwind 2 x 8 cm and e double unroll

Visualization bath in 0.1% w / v Fast Blue B (water)

The following conditions were used in the reversed-phase TLC analysis:

Stationary phase: C18 coated silica gel

Mobile phase 6: 7: 16 0.25% v / v acetic acid (aq) / methanol / acetonitrile

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Unwind 2 x 8 cm and e double unroll

Visualization bath in 0.1% w / v Fast Blue B (water)

For each sample on the TLC plate, the volume of the solution containing approximately 1 g of total cannabinoid was used.

Results and discussion

The ethanol solutions of the reference BDS (THC) and the reference BDS (CBD) are quite intense yellow. Passage of the BDS solutions through the activated charcoal effectively discolored the solutions, presumably by adsorbing the plant pigments co-extracted with the cannabinoids during the production of BDS from the hemp herb by liquid CO2 extraction.

The HPLC analysis results for the various BDS solutions are given in Table 12 below. They are also shown graphically (Graphs 1-3). All data are given in% of the tO determination. CBN values ​​are given for BDS (THC) solutions as this compound was identified as an indicator of thermal degradation of THC in previous stability studies.

Table 12

Cannabinoid determination values ​​for standard and purified BDS solutions within 1-12 months at 40 ° C

<td>Months</td><td></td><td> 1</td><td> 4</td><td> 6</td><td> 12</td>

<td>Exemplary BDS</td><td>THC</td><td> 97,3%</td><td> 92,4%</td><td> 85,3%</td><td> 74,0%</td>

<td>(THC)</td><td>CBN</td><td> 104%</td><td> 119%</td><td> 133%</td><td> 154%</td>

<td>BDS Cleaned</td><td>THC</td><td> 102,9%</td><td> 107,4%</td><td> 96,0%</td><td> 88,6%</td>

<td>(THC)</td><td>CBN</td><td> 94%</td><td> 111%</td><td> 111%</td><td> 120%</td>

<td>Reference BDS (CBD)</td><td>CBD</td><td> 100,3%</td><td> 103,6%</td><td> 93,3%</td><td> 91,0%</td>

<td>Purified BDS (CBD)</td><td>CBD</td><td> 101,0%</td><td> 100,7%</td><td> 97,2%</td><td> 96,9%</td>

It is quite clear from the above data that for both BDS (THC) and BDS (CBD), there is a certain component of ballast that can be removed with activated charcoal that destabilizes the cannabinoids.

A comparison of the degradation levels achieved after 12 months at 40 ° C for the reference BDS and the corresponding charcoal-purified BDS shows that for both THC extracts and CBD extracts, charcoal purification increases resistance to thermal degradation by more than 50 %.

Regarding BDS (THC), an increase in CBN levels was found as a function of depletion of the major cannabinoid (Figure 3). As has been observed with other THC-containing formulations, it is reaffirmed that CBN levels are indicative of thermal degradation.

A comparison between the cannabinoid regions of the HPLC chromatograms of the BDS (CBD) reference samples and the BDS (CBD) purified after 12 months at 40 ° C (data not shown) did not reveal any significant information. However, a similar comparison of the HPLC BDS (THC) chromatograms of the standard and purified degradation provided information.

CBN was more abundant in the more degraded crude standard BDS, but a second significant degradation product was also observed which is again present in both samples but which is more abundant in the more degraded sample. Again, the spectrum of this degradation product was substantially identical to and based on the CBN spectrum, and the retention time appeared to be one of the retention times of the CBN equivalents.

Proposal

By simple treatment with activated charcoal, a significant improvement in resistance to thermal degradation is achieved.

Example 3 - Effect of adding modifying agent in CO extraction₂ hemp plant material

The example below shows the effect of adding a polar cosolvent on the properties of an extract made from hemp plant material (chemical variety G5) using liquid CO2 extraction and illustrates the selectivity differences obtained using subcritical CO2 extraction versus supercritical extraction.

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Experimental details

Extraction experiments were performed using a 1 liter CO2 extraction device. Food grade CO2 and BP grade absolute ethanol were used as solvents.

A batch of G5 hemp (a chemical variety with high CBD content) was used. The CBD content was 7.3% w / w after decarboxylation. The cannabinoid content of the extracts was analyzed by HPLC.

Results and discussion

The composition data of the final extract obtained after a 4-hour extraction period under specified conditions are presented below in Table 13.

Table 13

Composition and yield data for extracts produced under different extraction conditions

<td>A sample</td><td>Extraction conditions</td><td>% w / w extract</td><td>% CBD (w / w)</td><td>% CBD yield</td>

<td>AC470</td><td>10 ° C / 60 bar</td><td> 8,45</td><td> 63,65</td><td> 72,9%</td>

<td>AC471</td><td>40 ° C / 100 bar</td><td> 10,7%</td><td> 54,4</td><td> 579,5%</td>

<td>AC472</td><td>40 ° C / 100 bar + 2% ethanol</td><td> 10,3%</td><td> 64,65</td><td> 91,0%</td>

The yield efficiency is based on the CBD available in the decarboxylated plant material loaded into the tank for each extraction.

The results illustrate that changing the extraction conditions from subcritical to supercritical increases the solvating capacity of CO2 and results in a higher yield of available CBD. However, supercritical CO2 can now dissolve a wider variety of compounds, and the extraction of this additional compound reduces the concentration of CBD in the extract to such an extent that it is now lower than the concentration obtained in the subcritical extraction. Thus, the marginal additional yield of available CBD from raw material would not compensate for this disadvantage and is evidence that the use of supercritical conditions is not advisable.

The addition of 2% w / w absolute ethanol to supercritical CO2 modifying agent increases the yield of available CBD to> 90%. Presumably the relatively polar cannabinoid is more soluble in the polarity increased extract.

Interestingly, the addition of a polar modifying agent slightly increases the concentration of CBD in the extract. This would seem to indicate that the coextractable non-cannabinoid material present in the plant material is less polar than the target cannabinoid and therefore the extraction of this material (ballast) is discarded as polarity increases. Thus, the extraction of the hemp plant material with supercritical CO2 + 2% w / w ethanol increases the yield of the target active compound without the concomitant drawback of loss of selectivity.

Summary

1. The transition from subcritical to supercritical conditions has little benefit in terms of the total cannabinoid yield from the raw material, but has the disadvantage of reducing the active extract content.

2. The addition of a modifying agent to supercritical CO 2 - 2% absolute ethanol - results in a significant improvement in the yield of cannabinoid from the feed, without the disadvantage of diluting the active content with the co-extracted material.