GB2391865A - Improvements in the extraction of pharmaceutically active components from plant materials - Google Patents

Improvements in the extraction of pharmaceutically active components from plant materials Download PDF

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Publication number
GB2391865A
GB2391865A GB0218901A GB0218901A GB2391865A GB 2391865 A GB2391865 A GB 2391865A GB 0218901 A GB0218901 A GB 0218901A GB 0218901 A GB0218901 A GB 0218901A GB 2391865 A GB2391865 A GB 2391865A
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United Kingdom
Prior art keywords
thc
cbd
temperature
range
extraction
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GB0218901A
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GB2391865B (en
GB0218901D0 (en
Inventor
Brian Anthony Whittle
Colin Anthony Hill
Ian Ronald Flockhart
David Victor Downs
Peter Gibson
Gary William Wheatley
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GW Pharma Ltd
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GW Pharma Ltd
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Priority to GB0218901A priority Critical patent/GB2391865B/en
Publication of GB0218901D0 publication Critical patent/GB0218901D0/en
Priority to PL375357A priority patent/PL205945B1/en
Priority to KR1020057002527A priority patent/KR101113162B1/en
Priority to PL388837A priority patent/PL226646B1/en
Priority to AU2003253002A priority patent/AU2003253002B2/en
Priority to DE10337458A priority patent/DE10337458B4/en
Priority to DK10180464.9T priority patent/DK2311475T3/en
Priority to PT03787897T priority patent/PT1536810E/en
Priority to PT101804649T priority patent/PT2311475T/en
Priority to PCT/GB2003/003566 priority patent/WO2004016277A2/en
Priority to ES10180464.9T priority patent/ES2592531T3/en
Priority to CA2994322A priority patent/CA2994322A1/en
Priority to EP03787897A priority patent/EP1536810B1/en
Priority to MXPA05001621A priority patent/MXPA05001621A/en
Priority to SI200332204T priority patent/SI1536810T1/en
Priority to CA2823474A priority patent/CA2823474A1/en
Priority to DK03787897.2T priority patent/DK1536810T3/en
Priority to ES03787897T priority patent/ES2392510T3/en
Priority to CN038242117A priority patent/CN1691954B/en
Priority to EP10180464.9A priority patent/EP2311475B1/en
Priority to CA2455129A priority patent/CA2455129C/en
Priority to JP2004528675A priority patent/JP4657716B2/en
Publication of GB2391865A publication Critical patent/GB2391865A/en
Priority to ZA200501169A priority patent/ZA200501169B/en
Application granted granted Critical
Publication of GB2391865B publication Critical patent/GB2391865B/en
Priority to HK05110252.7A priority patent/HK1076249A1/en
Priority to JP2010149763A priority patent/JP5235206B2/en
Priority to CY20121101035T priority patent/CY1113375T1/en
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Expired - Lifetime legal-status Critical Current

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K31/00—Medicinal preparations containing organic active ingredients
    • A61K31/33—Heterocyclic compounds
    • A61K31/335—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin
    • A61K31/35—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin having six-membered rings with one oxygen as the only ring hetero atom
    • A61K31/352—Heterocyclic compounds having oxygen as the only ring hetero atom, e.g. fungichromin having six-membered rings with one oxygen as the only ring hetero atom condensed with carbocyclic rings, e.g. methantheline 
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
    • Y02A50/30—Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change

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  • Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Pharmacology & Pharmacy (AREA)
  • Epidemiology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Medicines Containing Plant Substances (AREA)

Abstract

The invention relates to the extraction of pharmaceutically active components from plant materials. In particular it relates to cannabinoids obtained by extraction from cannabis. High purity tetrahydrocannibinol or cannibidiol may be extracted using sub-critical CO Þ extraction, decarboxylation and solvent extraction. Ethanol may be used to modify the liquid CO Þ .

Description

IMPROVEMENTS IN THE EXTRACTION OF PHUJUMACEUTICALLY ACTrVE COMPONENTS FROM
PLANT MATERIALS
The present invention relates to the extraction of 5 pharmaceutically active components from plant materials, and more particularly to the preparation of a botanical drug substance (BDS) for incorporation in to a medicament. It also relates to a BDS of given purity, for use in pharmaceutical formulations. In particular it relates to BDS comprising 10 cannabinoids obtained by extraction from cannabis.
In PCT/GB02/00620 the applicant discloses a method of preparing a herbal drug extract (botanical drug substance) from medicinal cannabis. The process comprises: 15 1. a heating step to decarboxylate the acid form of the cannabinoids to their neutral form; 2. a first extraction with a specified volume of liquid carbon dioxide for 6- 8 hours; and 3. a step to reduce the proportion of non-target materials, 20 referred to as winterisation, which step precipitates out waxes.
More specifically, PCT/GB02/00620 describes a process wherein: step 1 comprises heating chopped cannabis (2-3mm) at 100-150 C 25 for sufficient time to allow decarboxylation; step 2 comprises CO2 extraction using: a) a coarse powder (the particles are passed through a 3mm mesh); b) a packing density of 0.3; and 30 c) supercritical conditions of 600 bar at 35 C for 4 hours, although other combinations of temp and pressure ranging from 10-35 C and 60-600 bar (both super critical and sub critical conditions) could, it is acknowledged, be used; and step 3 comprises conducting an ethanolic precipitation at -20 C 35 for 24 hours and removing the waxy material by filtration.
The supercritical method disclosed in PCT/GB02/00620 produced: 40 a) a high THC extract containing:
60% THC
1-2% CBD
4-5% other minor cannabinoids including CBN (Quantative yields were 9% wt/wt based on dry weight of 5 medicinal cannabis); and b) a high CBD extract containing: 60% CBD:
4% THC
10 2% other cannabinoids (Quantative yields were 9% wt/wt based on dry weight of medicinal cannabis).
r Clearly as the resulting BDS is to be used in a 15 pharmaceutical product it is essential that the process is safe, scalable to GMP and gives high degrees of product consistency and, preferably also good yields. -
The principles of supercritical fluid extraction (SFE) 20 have been known since the work of Baron Cagniard de le Tour in 1822 when it was noted that the gas-liquid boundary disappeared when the temperature of certain materials was increased by heating them in a closed glass container. From this early work the critical point of a substance was first discovered. The 25 critical point is the temperature above which a substance can coexist in gas, liquid and solid phases. It was later found that by taking substances to or above their critical temperature i and pressure they could be used as sophisticated solvents for extraction and fractionation of complex mixtures.
The technique is widely used in the fuel oil processing business and has been applied to, for example, the purification and separation of vegetable and fish oils I 35 An attractive feature of SEE over the use of conventional solvents is that the solvent power (E ) can be varied by manipulation of temperature and pressure above the critical point. 40 In a typical pressure-temperature diagram for a substance i
- 3 - there are three lines which define the equilibrium between two of the phases. These lines meet at the triple point. The lines define the interface between gas, liquid and solid states, and points along the line define the equilibrium between pairs of 5 phases. For example, the vapour pressure (boiling point) curve starts at the triple point and ends at the critical point. The critical region starts at this point and a supercritical fluid is any substance that is above its critical temperature (Tc) and critical pressure (Pc). The critical temperature is thus the 10 highest temperature at which a gas can be converted to a liquid by an increase in pressure and the critical pressure is the highest pressure at which a liquid can be converted into a traditional gas by increasing the temperature. In the so-called critical region, there is only one phase and it possesses some 15 of the properties of both a gas and a liquid.
There are a number of solvents, which can be used for extraction of active substances from plant materials, and Table 1 shows the critical temperature and pressures for some of these 20 solvents. Table l: Critical Conditions for Solvents Solvents Critical Temperature ( C) Critical Pressure (bar) Carbon dioxide 31. I 73.8 Ethane 32.2 4B.8 Ethylene 9.3 50.4: Propane 96.7 42.5 Propylene 91.9 46.2 Cyclohexane 280. 3 40.7 Isopropanol 235.2 47.6 Benzene 289.0 48.9 Toluene 318.6 41.1 p- Xylene 343.1 35.2 Chlorotrifluoromethane 28.9 39.2 Trichlorofluoromethane 198.1 44.1 Ammonia 132.5 112.8 Water 374.2 220.5 2S The applicant has selected as a preferred solvent carbon dioxide, which has a critical temperature of 31.1 C and a critical pressure of 73. 8 bar.
30 Carbon dioxide is particularly advantageous because it is
available in plentiful supply, at low cost, and can if necessary be recycled. Any losses of CO2 are also ecologically neutral.
Furthermore, CO2 extraction is a conservative method of preparation and quite fragile molecules can be extracted with 5 precision.
A key consideration in the initial selection of liquid CO: as the solvent for the production of a high potency standardised extract of cannabis herb was the high degree of selectivity 10 which can be achieved. In the CO2 system it has been determined that solvating power can primarily be regarded as being a function of density and temperature, with the solvent density being the more important factor.
15 Contrary to expectation the applicant has determined that cannabinoids are best obtained under sub-critical rather than super-critical conditions By carefully controlling temperature and pressure below 20 the super-critical temperature and pressure the applicant has been able to separate out specific lipophilic or hydrophilic; fractions rich in cannabinoids with other components which can be separated relatively easily to obtain a botanical drug substance (BDS) which contains the desirable components in a 25 form which is pharmaceutically acceptable. Thus compounds which are known to be active substances can be separated from complex mixtures which occur in botanical raw material.
Furthermore, very good batch-to-batch reproducibility can 30 be obtained between batches and unwanted constituents, such as heavy metals, which may be present to varying extents in the botanical raw material, can be left behind in the exhausted material. 35 Extraction conditions can also be modified to reject pesticide residues which may be present in the original material. The benefits of using sub-critical conditions include the 40 selective nature of the extraction. In contrast, the applicant
found that with SEE the solvent, as well as solubilising the desirable cannabinoids, disadvantageously solubilised other non target materials which proved difficult to separate out in a subsequent clean-up step.
To explain, the density of sub-critical CO2 is low, and remains low even as pressure is increased until the critical point of the system is reached. Thus, whilst the solvating power of sub-critical CO2 is reduced a high degree of selectivity can 10 be achieved, as only the most soluble components are efficiently dissolved by the COz; in this case the cannabinoid fraction. The result is the production of a relatively simple extract containing, as well as the cannabinoids, only a limited number of non-target compounds, many of which can be removed relatively IS easily in a simple step. Furthermore, the cost savings made by operating at relatively low pressures and temperatures are a further benefit.
In contrast, above the critical temperature of 31 C, there 20 is a significant increase in the density of the CO2 as it now exists in a supercritical fluid state. This has the effect of greatly increasing the solvating power of the solvent, which whilst generally advantageous in that more cannabinoids are solubilised thereby giving high yields, in fact proves 25 disadvantageous because the decreased selectivity of the more powerful solvent results in increased volubility of a range of non- target compounds which makes the resulting extract harder to purify. In other words, it results in the production of more complex extracts in which the concentration of the target 30 compound may be significantly diluted (i.e. the potency of the extract is decreased).
In a first aspect the invention provides a method of extracting cannabinoids from plant material comprising a 35 decarboxylation step, an extraction with liquid carbon dioxide (CO?), and a step to reduce the proportion of non-target materials in the extract, characterized in that the extraction with liquid CO2 is conducted under sub-critical conditions at a temperature of between 5-15 C and a pressure of between 50-70 40 bar.
- 6 - The method of the invention may be used to prepare a cannabinoidrich extract from cannabis plant material. In a preferred embodiment, the method may be used to produce a 5 cannabis extract which is a botanical drug substance.
In the context of this application a "botanical drug substance" is an extract derived from cannabis plant material, which extract fulfils the definition of "botanical drug 10 substance" provided in the Guidance for Industry Botanical Drug Products Draft Guidance, August 2000, US Department of Health and Human Services, Food and Drug Administration Centre for Drug Evaluation and Research of: "A drug substance derived from one or more plants, algae, or macroscopic fungi. It is prepared 15 from botanical raw materials by one or more of the following 2 processes: pulverization, decoction, expression, aqueous extraction, ethanolic extraction, or other similar processes."
"Plant material" is defined as a plant or plant part (e.g. 20 bark, wood, leaves, stems, roots, flowers, fruits, seeds, berries or parts thereof) as well as exudates, and includes material falling within the definition of "botanical raw material" in the Guidance for Industry Botanical Drug Products Draft Guidance, August 2000, US Department of Health and Human 25 Services, Food and Drug Administration Centre for Drug Evaluation and Research.
The method of the invention may be used to extract cannabinoids from any plant material known to contain such 30 cannabinoids. Most typically, but not necessarily, the "plant material" will be "plant material" or "botanical raw material" derived from one or more cannabis plants.
The term "Cannabis plant(s)" encompasses wild type 35 Cannabis sativa and also variants thereof, including cannabis chemovars which naturally contain different amounts of the individual cannabinoids, Cannabis sativa subspecies indica including the variants var. indica and var. kafiristanica,! Cannabis indica and also plants which are the result of genetic
crosses, self-crosses or hybrids thereof. The term "Cannabis plant material" is to be interpreted accordingly as encompassing plant material derived from one or more cannabis plants. For the avoidance of doubt it is hereby stated that "cannabis plant 5 material" includes dried cannabis biomass.
The extraction with liquid COz is preferably carried out at a temperature between 8-12 C, most preferably at a temperature of about loach The extraction with liquid CO2 is preferably carried out at a pressure between 55-65 bar, most preferably at a pressure of substantially 60 bar.
IS Most preferably the CO2 has a mass flow of from 1000-1500 Kg/h, more preferably a mass flow of substantially 1250 Kg/h.
Preferably the liquid CO2 extraction is run for up to 10 hours, most preferably about 8 hours.
In a preferred embodiment liquid CO2 is removed by depressurisation and the recovered extract held at a temperature in the range from -15 C to 200C.
25 The step to reduce the proportion of non-target materials in the botanical drug substance may be essentially any treatment that results in selective removal of undesirable components (as opposed to cannabinoids), such that the amount of the undesirable components present in the final botanical drug 30 substance product is reduced. "Non-target" materials are any materials derived from the starting plant material that are not desired to be present in the final botanical drug substance. In a preferred embodiment this step may comprise a precipitation with a C1-C5 alcohol, wherein the material to be treated in the 35 alcohol precipitation step is warmed to above room temperature before the Cl-C5 alcohol is added. Typically, the step to reduce the proportion of nontarget materials in the botanical drug substance is carried out after extraction with liquid CO2,
in which case the "material to be treated'' in the alcoholic precipitation is the product of the liquid CO2 extraction. This extract is itself a "botanical drug substance" within the definition given above.
The Cl-C5 alcohol is preferably ethanol. The extract is preferably warmed to a temperature in the range from 36 C to 44 C, most preferably about 40 C. Warming of the material to be treated prior to addition of the ClCS alcohol has the effect of 10 improving mixing of this material with the C1-C5 alcohol, and hence improves the performance of the alcohol precipitation step. The C1-C5 alcohol is preferably added in an amount of from 15 3:1 to 1:1 C1-C5 alcohol vol to weight of the material to be treated, more preferably an amount of about 2:1 Cl-C5 alcohol vol to weight of the material to be treated.
The solution resulting from addition of C1-C5 alcohol to 20 the material to be treated is chilled and insoluble materials are allowed to precipitate out. Preferably the solution is chilled to a temperature in the range from -15 C to -25 C, and preferably the solution is chilled for up to 52 hours.
25 The precipitate of insoluble materials is then removed, typically by filtration. Preferably filtration is carried out through a 20pm membrane.
In a further preferred embodiment the method may further comprise a multistep evaporation under reduced pressure. This may be by rotary evaporation or other known techniques.
Typically the multi-step evaporation is carried out on the product of the C1-C5 alcohol precipitation step in order to 35 remove substantially all of the C1-C5 alcohol and water.
Preferably, the C1-C5 alcohol is removed first and then the water.
- 9 - The C1-C5 alcohol is preferably removed by heating to a temperature in the range of 58-62 C to give a vapour temperature in the range of 3842 C under a vacuum in the range of 168-172 mbar until there is little or no visible condensate.
Water is then additionally removed, preferably by a stepwise reduction of the vacuum in stages to about 50 mbar.
The decarboxylation step may be carried out prior to or 10 after extraction with liquid CO2.
In a preferred embodiment the decarboxylation step is carried out prior to extraction with liquid CO2 and is conducted by heating the plant material to temperatures and for times 15 which ensure at least 95% conversion of the acid cannabinoids from the acid form to their neutral form whilst ensuring thermal degradation of THC to CBN is less than 10%.
Decarboxylation of cannabinoid acids is a function of time 20 and temperature, thus at higher temperatures a shorter period of time will be taken for complete decarboxylation of a given amount of cannabinoid acid. In selecting appropriate conditions for decarboxylation consideration must, however, be given to minimizing thermal degradation of the desirable, pharmacological 25 cannabinoids into undesirable degradation products, particularly thernal degradation of THC to cannabinol (CBN).
Preferably, decarboxylation is carried out in a multi-step heating process in which the plant material is: 30 i) heated to a first temperature for a first (relatively short) time period to evaporate off retained water and allow for uniform heating of the plant material; and ii) the temperature is increased to a second temperature for a 35 second time period (typically longer than the first time period) until at least 95% conversion of the acid cannabinoids to their neutral form has occurred.
- 10 Preferably the first step is conducted at a temperature in the range of 100 C to 110 C for 10-20min. More preferably the first temperature is about 105 C and the first time period is about 15 minutes.
If the plant material is derived from cannabis plants having a high COD content (defined as >90% CBD as a percentage of total cannabinoid content) , the second temperature is preferably in the range from 115 C to 125 C, preferably about 10 120 C and the second time period is in the range from 45 to 75 minutes, preferably about 60 minutes. More preferably the second temperature is in the range from 135 C to 145 C, preferably 140 C and the second time period is in the range from 15 to 45 minutes, preferably about 30 minutes. In another embodiment, 15 most preferred for a mass of plant material greater than 4kg, the second temperature is in the range from 140 C to 150 C, preferably 145 C and the second time period is in the range from 55-90 minutes. The latter conditions are preferred for processing amounts of, for example, 4-6 kg of starting plant 20 material and the exact figures, particularly time, may vary slightly with increased mass.
If the plant material is derived from cannabis plants having a high THC content (defined as >90% THC as a percentage 25 of total cannabinoid content), the second temperature is preferably in the range of 115 C to 125 C, typically 120 C, and the second time period is preferably in the range of 45 minutes to 75 minutes, typically about 60 minutes. More preferably the second temperature is in the range of 100 C to 110 C, typically 30 105 C, and the second time period is in the range of 60 to 120 minutes. In another embodiment, most preferred for a mass of plant material greater than 4kg, the second temperature is in the range of 140 C to 150 C, preferably 145 C, and the second time period is in the range of 45 to 55 minutes.
Most preferably the decarboxylation step is conducted at temperatures and for times which ensure at least 97% conversion of the acid cannabinoids to their neutral form, whilst ensuring
- 1 1 thermal degradation of THC to CBN is less than 5%.
Standard conditions for cannabinoid assays, and methods of calculating cannabinoid content (as \) are given in the 5 accompanying Examples.
The plant material used as the starting material for the extraction process is preferably ground, milled or otherwise processed to give a particle size of less than 2mm, but 10 preferably greater than 1 mm. Such treatment generally results; in improved extraction of cannabinoids from the plant material, as packaging density is improved.
In a preferred embodiment the method of the invention may 15 further comprise a step of treating an extract (or botanical drug substance material) derived from the plant material with activated charcoal.
Typically, this step will be carried out on the product of 20 a precipitation with C1-C5 alcohol, usually immediately following filtration to remove the precipitate. The liquid product of the alcoholic precipitation is classified as a "botanical drug substance" according to the definition given above. Conveniently, treatment with activated charcoal may be 25 carried out by passing liquid material to be treated down an activated charcoal column.
As illustrated in the accompanying examples, treatment with activated charcoal significantly improves the stability of I 30 botanical drug substances derived from cannabis plant material, significantly improving resistance to thermal degradation of the active cannabinoids.
In a preferred embodiment the method of the invention will 35 comprise the following steps, preferably carried out in the stated order starting from cannabis plant material: i) decarboxylation, ii) extraction with liquid CO2, to produce a crude botanical drug
- 12 substance, iii) precipitation with C1-C5 alcohol to reduce the proportion of non-target materials, iv) filtration to remove the precipitate, 5 v) evaporation to remove C1-C5 alcohol and water, to produce a final botanical drug substance (ADS). i A step of treatment with activated charcoal may be included between step iv) and step v), resulting in improved 10 stability of the final BDS.
The applicant has further determined that the addition of a proportion of modifier or polar solvent, for example a Cl to C5 alcohol, as exemplified by ethanol, to liquid carbon dioxide 15 solvent may further increase selectivity of the extraction process. Accordingly, the invention further provides a method of extracting cannabinoids from plant material comprising an 20 extraction with liquid CO2, characterised in that an organic modifier or polar solvent is added to the carbon dioxide.
Preferably the modifier or polar solvent is added in an amount of up to 10% by weight.
Preferably the modifier is a C1-C5 alcohol, most preferably ethanol.
In a further aspect the invention further relates to 30 botanical drug substances derived from cannabis plant material.
Therefore, the invention provides a botanical drug substance obtainable from botanical raw material from a high THC containing cannabis plant having a THC content of at least 90%.
w/w of total cannabinoid content, wherein said botanical drug 35 substance is an extract derived from the high THC cannabis plant comprising at least 50\ THC w/w of extract, no more than 5% COD w/w of the THC content, and no more than 5% cannabinoids other than THC and CBD w/w of the THC content.
- 13 The %THC wt/wt of extract is more preferably at least 55%, and more preferably still at least 60%. The other cannabinoids and the assay methodology for determining the amounts are given 5 later.
The invention also provides a botanical drug substance obtainable from botanical raw material from a high CBD containing cannabis plant having a CBD content of at least 90% 10 w/w of total cannabinoid content, wherein said botanical drug substance is an extract derived from a high CBD cannabis plant, which extract comprises at least 50% CBD w/w of extract, no more than 7.5% THC w/w of the CBD content, and no more than 5% cannabinoids other than CBD and THC expressed as % w/w of the 15 CBD content.
The skilled man will appreciate that high THC plants such as, for example, "Skunk" have been bred, albeit for recreational use, using traditional breeding techniques which can likewise be 20 used to develop plants rich in other cannabinoids e.g CBD by natural selection or by genetic techniques as the genes for cannabidiolate synthase and THC synthase have been identified, see JP 2001029082 and JP2000078979. CPRO 921018 Land race Turkey is an example of high CBD plant.
The botanical drug substances may be obtained starting from cannabis plant material (botanical raw material) using the extraction method according to the invention.
30In a preferred embodiment the botanical drug substance comprises no more than 9ppb aflatoxin.
In a further preferred embodiment the botanical drug substance comprises no more than 20ppm total heavy metals.
In a further preferred embodiment the botanical drug substance comprises no more than 15% w/w residual solvents, more specifically no more that 15% w/w ethanol.
In a further preferred embodiment the botanical drug substance comprises no more than 105 cfu/g TVC (Total Viable Count), no more than 104 cfu/g fungi, no more than 103 cfu/g 5 enterobacteria and other non gram negative organisms, and no detectable E. coli, Salmonella or S. aureus.
The above-listed parameters relate to purity of the botanical drug substance and define a level of purity which is 10 preferred if the botanical drug substance is to be incorporated into a pharmaceutical product. Botanical drug substances having the required level of purity may be obtained using the extraction process according to the invention, particularly using the operating conditions and quality control procedures 15 described in the accompanying examples. Standard assay techniques for use in determining the levels of alfatoxin, heavy metals, residual solvents and bacterial contaminants in a botanical drug substance are known in the art (e.g. Ph.Eur standard procedures) and further details are provided in the 20 accompanying Examples.
Botanical drug substances prepared from cannabis plant material according to the methods of the invention may be formulated with one or more pharmaceutically acceptable 25 carriers, diluents or excipients or deposited on a pharmaceutically acceptable surface for vaporization in order to produce pharmaceutical formulations containing cannabinoids as the pharmaceutically active agents.! 30 Therefore, in a further aspect the invention provides a method of making a pharmaceutical composition comprising, as an active agent, a botanical drug substance which is an extract from at least one cannabis plant variety, which method comprises preparing a botanical drug substance containing cannabinoids 35 from the at least one cannabis plant variety using the I extraction method according to the invention, and formulating the botanical drug substance with one or more pharmaceutically acceptable diluents, carriers or excipients or depositing the
- 15 -
botanical drug substance on a pharmaceutically acceptable surface for vaporization to produce a pharmaceutical composition. 5 Separate botanical drug substances may be prepared from single cannabis plant varieties having differing cannabinoid content (e.g. high THC and high COD plants) and then mixed or blended together prior to formulation to produce the final pharmaceutical composition. This approach is preferred if, for lO example, it is desired to achieve a defined ratio by weight of individual cannabinoids in the final formulation.
Alternatively, botanical raw material from one or more cannabis plant varieties of defined cannabinoid content may be mixed together prior to extraction of a single botanical drug IS substance having the desired cannabinoid content, which may then be formulated into a final pharmaceutical composition.
The botanical drug substance may be formulated with any convenient pharmaceutically acceptable diluents, carriers or 20 excipients to produce a pharmaceutical composition. The choice of diluents, carriers or excipients will depend on the desired dosage form, which may in turn be dependent on the intended route of administration to a patient. Preferred dosage forms include, inter alla, liquid dosage forms for administration via 25 pump-action or aerosol sprays, tablets, pastilles, gels, capsules, suppositories, powders, etc and vapourisers. Such dosage forms may be prepared in accordance with standard principles of pharmaceutical formulation, known to those skilled in the art. Preferred dosage forms, and methods of preparing 30 such dosage forms, are described in the applicant's co-pending International application PCT/GB02/00620.
Liquid formulations are particularly preferred. A particularly preferred formulation for administration of 35 cannabinoids, though not intended to be limiting to the invention, is a liquid formulation comprising the botanical drug substance, ethanol and propylene glycol, and optionally a I flavouring, such as peppermint oil. This formulation may be
- 16 -
conveniently administered to the buccal or sublingual mucosae via a pumpaction spray, and provides for efficient absorption of the active cannabinoids.
5 The various aspects of the inventions are further illustrated, by way of example only, by the following examples, together with the accompanying Figures, in which: Eigure 1 illustrates loss of THC over time at 40 C for standard 10 THC botanical drug substance (BDS) and activated charcoal treated THC BDS (purified BDS). Y-axis: amount of THC (expressed as percentage of tO value), x-axis: time in months. Figure 2 illustrates loss of CBD over time at 40 C for standard 15 CBD
botanical drug substance (BDS) and activated charcoal treated CBD BDS (purified BDS). Y-axis: amount of CBD (expressed as percentage of tO value), x-axis: time in months.
Figure 3 illustrates formation of cannabinol (CBN) over time at 20 90 C for standard THC botanical drug substance (BDS) and activated charcoaltreated THC BDS (purified BDS). Y-axis: amount of CBN (expressed as percentage of tO value), x-axis: time in months.
25 Example 1-Development of a process for extraction of cannabinoids from cannabis plants Selection of cannabis chemovars Go Pharma Ltd has developed distinct varieties of Cannabis 30 plant hybrids to maximize the output of the specific chemical constituents, cannabinoids. Two types of plant are used; one chemovar produces primarily THC and a further chemovar produces predominately CBD. However alternative varieties can be obtained - see for example, Common cannabinoids phenotypes in 35 350 stocks of cannabis, Small and Beckstead, LLoydia vol 36b, 1973 pl44-156 and bred using techniques well known to the skilled man to maximise cannabinoid content Chemical and structural similarities exist between THC and I 40 CBD. Due to these similarities together with the botanic origin
- 17 -
of the starting materials, each can be considered to be interchangeable with respect to the development of processes for extraction of cannabinoids.
5 Preferably, each Cannabis chemovar is processed and controlled separately to yield two distinct BDS's. However, it is possible to mix plant material from two or more chemovars or use a variety which will produce the desired ratio of given cannabinoids prior to extraction, and thus prepare a single BDS.
Pr du tlon of boca:.i: r:7 material BDS is prepared from extracts of Cannabis saliva L. (family Cannabidaceae). Cannabis sativa was described in the 15 1934 British Pharmacopoeia. Cannabis is grown under United Kingdom Home Office licence under the control of GW Pharma Ltd in the United Kingdom. Growing facilities are equipped with shades and full climatic control (temperature, humidity and high intensity lighting) so that several crops per year can be 20 produced in almost identical growing conditions thus ensuring continuity of supply.
Cultivation: Cannabis plants are propagated from cuttings taken from 25 the mother plants, originating from a single seed source. i Therefore a crop is produced through asexual propagation where the plants are all female. Propagation using cuttings controls genotype consistency.
30 The cuttings are rooted in compost supplied as pesticide free. The plants are watered and sustained release fertilizer is applied during the growing cycle. Through controlled growing conditions the plants take approximately 12 weeks to reach maturity. The plants are irrigated throughout their growing cycle with potable quality water No synthetic herbicides or pesticides are used in the 40 cultivation of Cannabis plants.
- 18 Compost: Efficient cultivation of Cannabis necessitates the supply of a reliably uniform growing media.
The compost provides a soft texture, high air porosity, ready wetting, low conductivity and balanced nutrient supply.
The compost consists of peat and added natural minerals including lime (magnesium and calcium carbonates) to provide pH 10 control of the compost during the growing cycle of the Cannabis plants. The compost contains an adequate supply of essential minerals and a minimum of minerals with known adverse effects on 15 the plants. Some minerals including manganese can be present in an insoluble form in compost and be released in a freely soluble form overtime. Controlling compost pH and monitoring irrigation to avoid waterlogging will control soluble manganese levels.
Compost pH is maintained above 5.5.
The compost is declared as pesticide free, as no pesticides or herbicides are added.
Fertiliser: 25 The compost contains fertilizer identifiable in two discrete forms, a base fertiliser and a slow release fertilizer.
Additional slow release fertilizer is applied to the plants during growing.
30 Disease and Pest Control: No artificial herbicides or pesticides are used during cultivation. Stringent hygiene conditions reduce ingress of pests and diseases.
35 By controlling the growing conditions, environmental stresses such as drought, insufficient light and unfavourable temperatures reduces the risk of disease.
Regular inspection of the plants during the growing cycle 40 allows for the detection of any rogue plants and pests. Rogue
- 19 male plants may arise, though weeds should be absent due to the controlled growing conditions and media. Frequent inspections and biological control methods are used to manage any pests and diseases that may occur Plant Collection: Through strict control of growing conditions the Cannabis plants reach maturity in approximately 12 weeks. In the last weeks of growth dense resinous flowers develop. By the end of 10 approximately week 11 the cannabinoid biosynthesis has slowed markedly, and the plants are ready for harvest.
The entire plant is cut and dried in a temperature and humidity controlled environment.
15 À Approximately 21 C.
À Approximately 38 - 45% RH.
Dried plant is physically assessed for end-point.
THC and CBD are the principle bioactive constituents in 20 the BDS. However, these constituents are present as biologically inactive carboxylic acids in the BRM.
À THCA
CBDA The acid forms slowly decarboxylate over time during drying.
25 The leaves and flowers are stripped from the larger stems to provide the Botanical Raw Material (BRM).
Storage of BRM: Under conditions of storage the loss on drying reaches 30 equilibrium of approximately 10. The storage conditions for the dried BRM will be dependent on the physical status of the BRM. 35 General storage conditions for BRM: À Protected from light.
Approximately 15 - 25 C or -20 C À Approximately 38 - 42% RH.
- 20 i Summary-production of a BRM:
Harvest of plants Drying (light exclusion) 10 BRM I
(contains: THCA + CBDA) Milling to less than 2000pm to reduce particle size Decarboxylation of acid form of cannabinoids (THCA +7CBDA) to produce neutral cannabinoids (THC + CBD)
Typical BRM specification derived from a high CBD variety is
illustrated in Table 2: Test Method Specification
Identification: - A Visual Complies - B TLC Corresponds to standard (for CBD & CBDA) Positive for CBDA - C HPLC/UV
Assay: In-house NLT 90% of assayed cannabinoids by CBDA + CBD (HPLC/UV) peak area Loss on Drying: Ph.Eur. NMT 15% Aflatoxin: * UKAS method NMT 4ppb Microbial: * * Ph.Eur.
- TVC NMT 107 cfu/g - Fungi NMT 105 ctu/g - E.coli NMT j o2 cfi/g Foreign Matter: Ph.Eur. NMT 2 % Residual Herbicides and Ph.Eur. Complies Pesticides:*** 25 Analytical Methods: Identification by Visual: Macroscopic characteristics allow the features of the Cannabis plant to be distinguished from potential adulterants and substitutes. It is a visual identification against a 30 photographic standard.
- 21 Identification by TLC: TLC uses both retention time and characteristic spot colour to effectively identify the variety of Cannabis.
5 Laboratory samples are prepared for TLC analysis by extracting the dried herb. An aliquot is spotted onto a TLC plate, alongside reference samples for THC and CBD. Following exposure to Fast Blue B reagent, THC and THCA present as pink spots, while CBD and CBDA are orange in colour. Neutrals can be 10 distinguished from the acids by comparison of the Rf value to r that obtained for the standards. Identity is confirmed by comparison of Rf and colour of the sample spot, to that obtained for the appropriate standard.
15 Identification by HPLC: HPLC uses retention time comparison of cannabinoids to effectively identify the variety of Cannabis. The reversed phase HPLC method is specific for CBD and CBDA, and therefore may be used as an identity test. Samples of biomass are 20 extracted and centrifuged. Detection of all analyses is 1 accomplished at 220 nm with additional confirmation of acidic analyses at 310 nm.
Assay (CBD + CBDA): i 95 This assay is used to monitor the CBD and CBDA content in J the plant. CBD and CBDA assay are determined using an HPLC method. The efficiency of the decarboxylation process is 30 determined by dividing the % content in terms of w/w of CBD by the total CBD + CBDA content. r Loss on Drying: Loss on Drying is evaluated using Ph.Eur. test method.
Aflatoxin: Aflatoxin is analysed using a United Kingdom Accreditation Service (UKAS) accredited method.
40 Microbial:
- 22 Microbiological quality is determined using Ph.Eur.
methodology. Foreign Matter: 5 Foreign Matter is evaluated using the Ph. Eur. test method.
Flowers, leaves and side stems are spread out in a thin layer on a clean laboratory surface. Foreign Matter is separated by hand as completely as possible, and is weighed. Results are expressed as % w/w of Foreign Matter in the herbal biomass 10 sample. Foreign Matter may comprise no more than 2% of the biomass. Residual Herbicides and Pesticides: The Cannabis plants are grown in a well controlled 15 environment. No artificial herbicides or pesticides are used or needed during cultivation An equivalent BRM specification (compare table 2) is
derived for a high THC variety and identical analytical methods 20 followed, except that THC/THCA replaces CBD/CBDA.
Decarboxylation THC and CBD are the principle bioactive constituents in Cannabis. However, these constituents are present as the 25 biologically inactive carboxylic acids in Cannabis plants. In order to extract THC or CBD from cannabis plant material, it is necessary to convert the storage precursor compounds of THCA and CBDA into their more readily extractable and pharmacologically active forms. THC and CBD acids slowly decarboxylate naturally 30 over time. The traditional way to increase rate of decarboxylation is by the application of heat. However, THCA is converted not only to THC, but also to another cannabinoid, cannabinol (CBN).
35 THCA or CBDA (C22H3004) 145 C THC or CBD (C21H30O2) The decarboxylation procedure is generally carried out within the preparation of the starting material or botanical material (BRM), prior to the initiation of the extraction 40 process.
- 23 Laboratory St udies - deca rboxylat i on Portions of milled dried plant material were subjected to heat (approximately 0.25g with particle size 1-2mm). A pilot 5 scale experimental system was set up, with the objective of determining parameters for the optimal conversion of THCA or CBDA into THC and CBD respectively, with concomitant minimal loss of these ensuing compounds into their thermal degradation products, in the case of THC the formation of CBN.
Brief Description of Materials and Methods:
Portions (0.25g) of milled (approximately 1-2 mm particle size) of both THCA and CBDA herbal materials were placed in 20-
ml glass headspace vials and the vials sealed tightly with crimp 15 capped Teflon-faced butyl rubber seals. Sealed vials were heated at one of three temperatures, for periods of up to 4hrs as follows: 105 C, 120 C, 140 C for 0.5, 1.0, 2.0 and 4.0 hours.
20 The heating was performed in an oven with forced air circulation. Oven conditions were shown to be accurate to within 0.5 - 1.0 degree at the three temperatures used.
After the heating process was complete representative 25 samples of the decarboxylated herb were assayed using HPLC, GC and TLC techniques. Standards of THC, CBD and CON were include in the HPLC and GC sequences.
Results and Discussions: 30 HPLC analysis of the solvent extracts was able to demonstrate the disappearance of either CBDA or THCA as a function of time at the two lower temperatures. At 190 C, the earliest tine point samples at 0.5 hour contained only very modest levels of a peak elating at the retention times of CBDA 35 or THCA.
Tables Sand 4 present HPUC data quantifying the conversion of CBDA or THCA into the free compounds; also presented is data showing the content of CBD or THC and the ratio of CBD/CBDA + 40 CBD or THC/THCA + THC. The conversion of the carboxylic acid
- 24 forms to the corresponding decarboxylated form can be monitored by comparing the decarboxylated / decarboxylated plus un decarboxylated ratio with the absolute content of the decarboxylated compounds. Thus, when the ratio reaches a 5 maximum value (> 0.95), the earliest time/temperature point at which the content of THC or CBD is also maximal, should be optimal for the conversion process.
Thus, for CBD containing herb, l hour at 120 C or 0.5 hour 10 at 140 C, was appropriate.
This is confirmed by examination of the TLC chromatogram for the solvent extracts, CBDA is absent after l hour at 120 C or at any time point at 140 C.
For THC there is a 3rd criterion, formation of CBN, where it is desirable to minimise the formation of this compound -
during the thermal decarboxylation process. Table 5 provides Gas Chromatography (GC) data where a CBN/THC ratio can be 20 derived. Taken into consideration, alongside the THC/THCA + THC -
ratio and the maximum THC content, minimal CBN formation occurs after 0.5 or 1.0 hour at 120 C. At 140 C, even 0.5 hour gives a higher content of CBN than either of the two lower time/temperature points.
Therefore laboratory studies demonstrate the optimum conditions for the decarboxylation of: Chemovar producing primarily CBD is 1 hour at 120 C or 0.5 hour at 140 C.
30 Chemovar producing primarily THC to minimise CBN -
formation, is 1 to 2 hours at 105 C or l hour at 120 C.
Thin layer chromatography reveals that virtually all of the THCA has disappeared after 4 hours at 105 C and after 1 hour at 120 C. No THCA is visible at any time point when the herb is 35 heated at 140 C. A small amount of residual staining at this retention value on TLC and the presence at low levels of a peak coincident with THCA on HPLC analysis may indicate the presence of a minor cannabinoid rather than residual THCA. =
- 25 Table 3:
HPLC Data from Decarboxylation of CODA Herbal Material . Temperature Time (hours) CBD/CBD + CODA COD peak area/O.lg of herb Zero 0.15 4769 0.5 0. 22 5262
1.0 0.86 5598
105 C 2.0 0.93 5251
4.0 0.98 5242
0.5 0.91 5129
1.0 0.97 5217
120 C 2.0 0.99 S037
9.0 1.00 5200
:: 0.5 0.96 5440
1.0 1.00 5105
140 2.0 1.00 5157
4.0 1.00 5005
5 Table 4
HPLC Data from Decarboxylation of THCA Herbal Material Temperature Time (hours) THC/THC + THC peak THCA area/O.lg of herb Zero 0.17 992.9 0.5 0. 87 5749
1.0 0.93 5273
105 C 2.0 0.98 7734
4.0 0.99 7068
_ 0.5 0.97 7189
1.0 0.99 6391
_.. 120 C 2.0 0.99 6500
_ _._ 4.0 1.00 5870
, 1 0.5 1 1.00 1 6724
1.0 1 1 00 1 5981
140 C 2.0 1.00 5361
4.0 1.00 q787 Table 5:
GC Data from Decarboxylation of THC Herbal Material Temperature Time (hours) CBN/THC (%) 0.5 3 5
1.0 4.2
105 C 4 0 5 6
0.5 3.2
1.0 4.1
120 2.0 6.7
4.0 11.3
0.5 5.7
1.0 13.0
140 C 2.0 17.5 =
4.0 23.8
The decarboxylation conditions for a batch scale of about 4 kg of botanical raw material (BRM) are as follows: Approximately 4kg of milled BRM (either THCA or CBDA) to be decarboxylated was initially heated to 105 C and held at this temperature for about 15 minutes to evaporate off any retained water and to allow uniform heating of the BRM. The batch was IS then further heated to 145 C and held at this temperature for 45 minutes to allow decarboxylation to be completed to greater than = 95% efficiency.
The heating time for CBDA BRM was extended to 55 minutes 20 at 145 C as it became apparent from results that CBDA was slightly more resistant to decarboxylation than THCA. This
- 27 difference between CBD and THC would be even more pronounced at commercial scale batches. The THC BRM heating time was retained at 145 C for 45 minutes.
5 The conditions used in pilot scale closely reflect those conditions determined as optimal from the laboratory studies.
The differences can be explained by slower and less efficient heat transfer via the containers and through the BRM at the increased batch size for the pilot scale.
Tables 6 and 7 provide data to demonstrate the efficiency -
of Decarboxylation measured in terms of content of the! biologically active cannabinoid, THC or CBD.) 15 Table 6:
Decarboxylation Efficiency for CBD BRM 2 Batch % Efficiency of Number Decarboxylation CBD Specification >95%
A 98.8
B 99.5 I
C 98.3 (
D 100.0 (
E 100.0
F 100 G 96.9:
H lOO.O; Increase in batch size of CBD BRM from approximately 4kg 20 to 6kg resulted in a need to increase Decarboxylation time. The Decarboxylation time at 145 C was increased from 55 minutes to t 90 minutes.
Table 7: l
_ Batch % Efficiency of Number THC Decarboxylation! _ _ Specification > 95%
I 99.4
- 28 I J 97.3
K 98.5
L 100.0
M 97.8
N 99.9
O 100.0
Overview of extraction process: 5 The BDS is extracted from decarboxylated BRM using liquid carbon dioxide methodology. This involves continuously passing liquefied carbon dioxide through the chopped biomass, which is contained in a high-pressure vessel. The crude extract is dissolved in ethanol, cooled to a low temperature then filtered 10 to remove precipitated constituents such as waxes. Removing ethanol and water in vacuo produces BDS containing either high concentrations of CBD or THC, depending on the biomass used.
Flow diagram of typical extraction process: BRM is decarboxylated by heating to approximately 105 C for 15 minutes, followed by approximately 145 C for minimum of 55 minutes for THCA and 90 minutes for CBDA.
Extraction with liquid carbon dioxide (CO2) [Food Grade] for up to 10 hours Conditions: Approximately 60 bar 10 bar pressure and 1 0 C 5 C 25 1; Removal of CO2 by depressurisation to recover crude extract 30 1 "Winterisation"-Dissolution of crude extract in ethanol followed by chilling solution t (-20 C 5 C/up to 52hours) to precipitate unwanted waxes t Removal of unwanted waxy material by cold filtration (20pm filter) 40 1! Removal of ethanol and water from the filtrate by thin film evaporation under reduced pressure (60 C 2 C, with vapour at 40 C 2 C / 172 mbar and 72 mbar+4mbar)
- 29 BDS 5 (Stored at-20 C+5 C) Extraction No.1 The first stage in the manufacturing process is Extraction 10 using liquid CO2 under subcritical conditions Experiments indicated that both THC and CBD could be extracted from Cannabis plant material in high efficiency using subcritical CO2 at low temperature, of approximately 10 C +5 C 15 using a pressure of approximately 60 bar ilObar.; The table 8 below shows comparative data generated for a BDS rich in THC Charge No Pressure Temp %w/w wax ithc w/w post.
bar C removed winterisation: Ac1202 400 60 8.2 67.2 _ Ac1205 400 60 6. 1 67.0 Ac1206 400 60 ---1 6.1 68.0 Three runs 60 10 2.2 - 4.8 59.9-73.7 _ Ave about 3 Ave 65% From the results it can be seen that there is loss of selectivity, as indicated by the high wax burden under super critical conditions. Whilst winterisation can remove larger amounts of wax, processing is difficult as, for example, filters 25 block. Similar results were obtained with CBD Preferred conditions for liquid CO2 extraction are as 30 follows: Decarboxylated botanical raw material is packed into a single column and exposed to liquid CO2 under pressure.
Batch size: Approximately 60kg
- 30 ' Pressure: 60 bar + 10 bar Temperature: 10 C + 5 C Time: Approximately 8 hours CO2 mass flow 1250kg/hr +20%.
Preferred process parameters for production of BDS are: extraction time > 10 hours, CO2 pressure 50-70 bar, extraction temp 5-15 C, CO2mass 167 kg/kg BRM i 10 Following depressurisation and venting off of the CO2 the t crude BDS extract is collected into sealed vessels. The original BRM reduces to approximately 10% w/w of crude BDS extract. The crude BDS extract is held at -20 C i 5 C.
15 The crude SDS extract contains waxes and long chain molecules. Removal is by "winterisation" procedure (extraction 2), whereby the crude BDS extract is warmed to e.g. 40 C + 4 C -
to liquefy the material. Ethanol is added in the ratio of 2:1 ethanol volume to weight of crude BDS extract. The ethanolic 20 solution is then cooled to -20 C + 5 C and held at this temperature for approximately 48 hours.
On completion of the winterisation the precipitate is removed by cold filtration through a 20pm filter.
Extraction No.2 The second stage in the manufacturing process is I Extraction No.2, referred to as "winterisation" using ethanol. I Crude BDS extract is produced from Extraction No.1 that contains 30 constituents, such as waxes. Ethanol effectively extracts long chained molecules from the crude extract.
Studies: It was found by warming the crude BDS extract to 35 approximately 40 C the mixing ability of the crude extract with solvent was improved.
It was preferred to chill the "winterisation" solution to -20 C for about 48 hours.
- 31 Preferred process parameters for production of BDS are: extraction temp 36-44 C, ratio ethanol: product approx. 2:1, freezer temp -25 C to 15 C, time 48-54 hours.
5 Filtration The ethanolic solution produced in the second extraction stage requires filtration to remove the resulting precipitation.
Filter size is preferably 20m.
10 Preferred process parameters for production of BDS are: total filtration time >6hours.
Evaporation The final stage of the manufacturing process is the 15 removal of ethanol and any water that may be present.
Preferably this is carried out by heating at 60 C + 2 C to give a vapour temperature of 40 C + 2 C under a vacuum of 172 mbar + 4 mbar. The distillation under these conditions continues until there is little or no visible condensate. Reducing the vacuum 20 further, in stages, down to approximately 50 mbar, completes water removal. On completion the BDS is transferred into sealed stainless steel containers and stored in a freezer at -20 C + 5 C. 2S Preferred process parameters for production of BDS are: evaporation vapour temperature 38-42 C, vacuum pressure removal of ethanol 167-177 mbar, vacuum pressure removal of water 70-75 mbar 62- 58 mbar 52-48 mbar, time <8 hours.
30 Characterisation of BDS The THC BDS is a brown, viscous, semi-solid extract consisting of at least 60% cannabinoids constituents. The cannabinoid constituents include at least 90% THC, about 1.5% 35 COD with the remainder being made up of other minor i cannabinoids. The chemical composition of Cannabis has been thoroughly studied with over 400 compounds identified (Hendricks et al., 40 1975; Turner et al., 1980). More than 60 cannabinoids have been
- 32 identified, with CBDA and THCA (the CBD and THC pre-cursors) being the most abundant. Generally' the non-cannabinoid constituents comprise up to 50% of extracts, depending on the extraction process. Chemical classes identified include alkanes 5 (25-30 carbon chain), nitrogenous compounds, amino acids, sugars, aldehydes, alcohols and ketones, flavanoids, glycosides, vitamins, pigments and terpenes. About 95 mono- and sesqui terpenes have been identified in Cannabis and are responsible for the characteristic odour.
Considerable work has been carried out to completely elucidate the structure of both CBD and THC (summarized in the above papers) and both have been prepared synthetically. Pure; THC has been successfully isolated in sufficient quantity from 15 the BDS to be used as reference material for identification and quantification. Impurities: The BDS substance is a selective extract from dried 20 decarboxy]ated leaves and flowering heads of specific chemovars! of Cannabis saliva. A range of over 400 compounds, including over 60 cannabinoids, have been found in Cannabis plants (Turner 1980). As these are naturally occurring it is not considered: necessary to deem any of these components as impurities. The I 25 major impurities therefore occur in four areas, pesticides introduced during the growing process, aflatoxins, any new products formed by decarboxylation and the materials other than the cannabinoids, which make up the BDS.
30 The growing process is closely controlled using GAP guidelines and takes place in a climate controlled indoor growing environment. No pesticides are applied to the crops during growth, all pest control being managed by biological means. No pesticides are incorporated in the growing medium.! 35 To ensure that no pesticide residues are introduced into the i product the growing medium is periodically tested for pesticides known to be used by the growing medium supplier.
Once the plant material has been harvested and dried 40 further samples are periodically tested using a general
- 33 -
pesticide screen to ensure no contamination of the crop has occurred Potential impurities are adequately controlled at the BRM stage.
* 5 Although the growing conditions are carefully controlled to prevent this, the raw material has the potential for t microbiological contamination resulting in aflatoxins in the product. The BRM and the BDS are therefore tested periodically for aflatoxins content.
The naturally occurring form of THC in the freshly grown ' plant is the acid THCA, although small quantities of the neutral I THC do occur. Before extraction the THCA is decarboxylated by heating to yield the neutral THC. The process is efficient but a 15 small amount of THCA remains and this is monitored during the 1 final testing of the BDS. Thermal degradation of the THCA and THC during the decarboxylation process is possible to yield CBNA and CBN. These are monitored in the BDS.
20 The non-cannabinoid components that make up the ballast portion of the BDS include hydrocarbon and triglyceride waxes, plant pigments and terpenes. These are common components of many other extracts of medicinal plants and are considered to be of little toxicological and pharmacological significance. The range 25 of other components present is wide but they are generally present in only small quantities: The quantity of ballast is reduced by the winterisation process which precipitates the waxes. The ballast materials are 30 considered to be a diluent of the active constituents and are not assayed or controlled. L
- 34 -
Table 9-Specification for the control of BDS high in CBD:
Test Test Method Limits Appearance In-House Brown viscous semi-solid Identification: -A TLC Spots have characteristic Rf and colours, - B HPLC/UV compared with CBD standard Positive for CBD CBD content In- house NLT 55 /0 w/w of extract (HPLC-UV)
Related cannabinoids: In-house -THC content (HPLC/UV) NMT 7.5% of the CBD content -Others (total) NMT 5% of the CBD content Aflatoxin: * TBA NMT 4 ppb Total Heavy Metals:** Ph.Eur. NMT 20 ppm Residual solvents: In-house Ethanol NMT 5% w/w Microbial: *** Ph.Eur.
-TVC NMT 105 cog -Fungi NMT 104 cfi/g -Other enterobacteria & NMT 103 chu/g certain other gram negative organisms -E.coli Absent in Ig Salmonella Absent in 10g -S.aureus Absent in Ig 5 Analvtical procedures Identification, Assay and Related Cannabinoids: The content of THC, CBD and Cannabinol (CBN) in the BRM and BDS, are quantitatively determined by extraction with 10 methanol or methanol / chloroform (9:1). Reverse-phase High Performance Liquid Chromatography (HPLC) with UV detection at 220nm is the method of quantification. All analysis must be performed under amber light because the compounds of interest are known to be light sensitive.
- 35 -
Chromatography Equipment and conditions: Equipment Agilent (HP)ll00 HPLC system with variable wavelength UV detector or diode array detector.
HPLC Column Discovery C8 5pm l5cm x 0.46cm 5 Pre-Column Kingsorb Cl8 5pm 3cm x 0.96cm Mobile Phase Acetonitrile: Methanol: 0.25% w/v acetic acid (16:7:6 by volume) Column Temp 25 C Flow Rate 1.Oml mind 10 Detection220nm 600mA f.s.d. Second wavelength 310nm Injection Volume l0pl Run Time 20-25 minutes (may be extended for samples containing small amount of late-eluting peaks) Elution Order CBD, CBDA, 69THCV, CBN, 69 THC, CBC, A9THCA Standard Preparation: Stock standard solutions of CBD, CBN and 63 THC in methanol at approximately lmg ml' are stored at -20 C.
Diluted working standards (0.1 mg/ml for a9 THC and CBD and 20 0.01 mg/ml for CBN) are prepared in methanol from the stock standards and stored at 20 C (maximum period of twelve months after initial preparation). After preparation, standard solutions must be aliquoted into vials to reduce the amount of standard exposed to room temperature. Prior to use in an HPLC 25 sample assay, the required number of standard vials are removed and allowed to equilibrate to room temperature.
Sample Preparation: In all preparations, alternative weights and volumes may 30 be used to give the same final dilutions.
Botanical Raw Material Accurately weigh approximately l00mg of chopped dried homogeneous material into a l0ml volumetric flask.
35 Disperse material in methanol: chloroform (9:l v/v) and make to volume in the same solvent.
Extract sample in an ultrasonic bath for 15 minutes.
Centrifuge an aliquot at 3000rpm for about 2 minutes.
À Dilute 100ul of the supernatant to lml with methanol in a 40 suitable HPLC sample vial (Further dilution may be required if
- 36 the principal cannabinoid concentration is outside the linear working range).
Decarboxylated Botanical Raw Material: 5 As for Botanical Raw Material.
Botanical Drug Substance: Accurately weigh approximately 80mg of BDS into a 50ml volumetric flask.
IO À Dissolve BDS and make up to volume with methanol.
À Dilute 1001 of the prepared supernatant to lml with methanol in a suitable HPLC auto sampler vial.
Chromatography Procedure: 15 Samples are placed in the autosampler rack in the order entered into the sequence list on the Agilent chemstation.
Standard solutions are used to provide quantitative and retention time data. These may be typically injected in duplicate or triplicate prior to the injection of any sample 20 solutions and then singularly at suitable intervals during the run, with a maximum of 10 test samples in between standards.
Chromatography Acceptance Criteria: 25 Table 10-Retention time windows and Relative Retention Time (RRT) to 69THC for each analyte: Cannabinoid Retention Time RRT(THC) (Minutes) CBD s. - 5.8 0.58 CBN 7.4 - 8.3 0.83
9 THC Do- o.o 1.00 CBDA s.s - 6.2 0.615 69 THCV s.g - 6.6 0.645 _ CBC 11. 6- 12.8 1.30
A9 THCA t4.6- 16.0 1.605 _.
- 37 Table 11-Peak Shape (Symmetry Factor according to British Pharmacopoeia method): Cannabinoid Symmetry Factor . __ _
CBD < 1.30
CON < 1.25
69 THC < 1.35
Calculation: Botanical Raw Material: The following equation is used to obtain a result for the 10 purity of the principal cannabinoid as a % of the currently assayable cannabinoids (CBD, CBDA, CON, a9 THC & Q9 THCA) in the batch: For high 69 THC material: %THC = peak area sum of THC & THCA x 100 peak area sum of assayable cannabinoids For high CBD material, CBD & CBDA replace THC & THCA in the top 20 line of the equation.
Decarboxylated Botanical Raw Material: The following equation is used to calculate the efficiency of the decarboxylation process: For high a9 THC material: % decarboxylation efficiency = Peak area of THC x 100 Peak area sum of THC & THCA For high CBD material, CBD & CBDA replace THC & THCA in the equation.
- 38 Botanical Drug Substance: The following equations are used to calculate the concentration of drug substance sample, the individual sample cannabinoid concentration, the % content of the assayable 5 cannabinoids in the drug substance, the quantity of principal cannabinoid as a 't of currently assayable cannablooids and the amount of principal cannabinoid in the whole weight of extracted drug substance.
10 For high 69 THC material: Concentration of drug substance sample = Weight of sample Dilution factor Where dilution factor = 50 x 10 = 500 Sample THC concentration = THC standard cone x mean THC sample area mean THC standard area %w/w THC content of drug substance = THC sample concentration x 100 drug substance sample concentration COD and CBN can be substituted into all of these equations instead of 69 THC to obtain quantitative results for both. 69 THCA and CBDA are also calculated using the standard concentrations for 69 THC or CBD in the absence of specific 30 reference standards of their own.
Related Substances are defined as the sum of the mean tw/w values for CON, &9 THCA and CBDA.
35 THC as % of total = % w/w THC content x 100 assayable cannabinoids sum of % w/w of all assayable cannabinoids The total amount of Q9 THC present in the whole drug 40 substance extract is obtained.
- 39 , Example 2-Investigation of the stabilization of botanical drug substance (BDS) by partial purification using activated charcoal 5 Results from stability studies on TEC formulations indicate that THC in the form of BDS is unstable even at storage temperatures as low as 5OC. This contrasts with the behaviour of the purified THC (Dronabinol USP) in Marinol soft gel capsules, for which a shelf life of 2 years at cool ambient 10 temperature is accepted. It should also be noted that the shelf life of THC standard solutions in methanol supplied by Sigma Aldrich is claimed to be 4 years when stored refrigerated and
protected from light.
This apparent discrepancy between the stability of BDS (THC) and purified THC prompted speculation that some component of BDS was destabilizing the principal cannabinoid.
A solution to this problem would be to purify the BDS 20 (THC) to yield high purity, preferably crystalline cannabinoid.
However, the additional processing costs incurred on transforming BDS to pure cannabinoid would substantially increase the cost of finished pharmaceutical products incorporating the cannabinoid.
Hence, the applicant sought to develop a simple purification step which would produce BDS with enhanced stability but which did not increase processing costs to a prohibitive extent.
The applicant has determined that a charcoal clean-up step may be conveniently carried out in close conjunction with the "winterisation" process by passing the ethanolic winterisation solution through a filter bed to remove 35 precipitated waxes and then directly through a charcoal column in a single step and that the use of activated charcoal significantly improves shelf life.
- so -
Experimental Detail.
Solutions of either BDS (THC) or BDS (CBD) at a concentration of 100 mg/ml in absolute ethanol BP were passed 5 through a column packed with activated charcoal and the eluate collected. These were then diluted with further absolute ethanol to achieve a concentration of cat 25 mg/ml cannabinoid.
The solution was then transferred into a lOml type AX1 (i.e. amber glass) vial and crimp sealed. These samples were 10 designated charcoal purified BDS.
Samples of the BDS (THC) and BDS (CBD) solutions which had not been passed through the charcoal column were similarly diluted to give a cannabinoid concentration of 25 mg/ml and were 15 then sealed in an amber glass vial of the same type. These samples were designated "standard BDS" and served as a control for the stability study.
The vials containing std BDS and charcoal purified BDS of 20 each type were stored in a stability incubator at 400C and samples then periodically withdrawn over the period 1 - 12 months for HPLC analysis of cannabinoid content and TLC profiling. 25 Normal phase TLC analysis employed the following conditions: Stationary Phase: Silica Gel G Mobile Phase: 80:20 hexane/acetone Development: 2 x 8 cm i.e. double development Visualisation: Dip in 0.1% w/v Fast Blue B (aq) Reverse phase TLC analysis employed the following conditions: Stationary Phase: C18 coated Silica Gel Mobile Phase: 6:7:16 0.25% v/v acetic acid (aq) /methanol/acetonitrile 3S Development: 2 x 8 cm i.e. double development Visualisation: Dip in 0.1% w/v Fast Blue B (aq) For each sample a volume of solution containing approximately 5 fig total cannabinoid was applied to the TLC plate.
- 41 Results and Discussion.
The ethanolic solutions of std BDS (THC) and std BDS (CBD) 5 are a fairly intense yellow. Passage of the BDS solutions through the activated charcoal effectively decolourised the solutions, presumably by the adsorption of plant pigments co-
extracted with the cannabinoids during the preparation of BDS from cannabis herb by liquid CO2 extraction.
The HPLC analysis results for the different BDS solutions are tabulated below as Table 12 and are also presented in graphical form (Figures 1-3). All data is reported as % of the tO assay. CBN values are included for the BDS (THC) solutions 15 as this compound has been identified as a marker of thermal degradation of THC in previous stability studies.
Table 12: Cannabinoid Assay Values for Std and Purified BDS Solutions over the Period 1-12 Months at 40OC 1 4 6 12
Months Std BDS THC 97.3% 92.4% 85.3% 74.0% 25 (THC) CBN 104% 119% 133% 154%
Purified THC 102.9% 107.4% 96.0% 88.6% BDS (THC) CBN 94% 111% 111% 120%
30 Std BDS CBD 100. 3% 103.6% 93.3% 91.0% (CBD) Purified CBD 101.0% 100. 7% 97.2% 96.9% BDS ( CBD)
From the above data it is quite clear that for both BDS (THC) and BDS (CBD) there is some component of the ballast, which can be removed by charcoal, which is destabilizing the cannabinoids.
- 42 Comparison of the levels of degradation reached after 12 months at 40.C for the std BDS and the corresponding charcoal purified BDS indicate that for both the THC and the CBD extracts the charcoal purification increases the resistance to thermal 5 degradation by over 50%.
For BDS (THC), the level of CBN is seen to increase as a function of the principal cannabinoid lost (Fig 3). As observed for other formulations containing THC, the level of CBN is again 10 confirmed to be a marker of thermal degradation.
I Comparison between cannabinoid regions of HPLC chromatograms of standard BDS (CBD) and purified BDS (CBD) samples after 12 months at 40C (data not shown) revealed no 15 significant information. However, similar comparison of HPLC chromatograms of the standard and purified BDS (THC) after degradation was informative.
The CBN was at a higher level in the more highly degraded 20 unpurified 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.
The spectrum of this degradation product was again essentially identical to that of CBN and on the basis of this and the 25 retention time appeared to be one of the CBN analogues.
Conclusion
I Significant improvement in resistance to thermal | degradation is achieved by a simple charcoal treatment.
Exam le 3-Effect of addition of or anic modifier on CO2 P g extraction of cannabis plant material 35 The following example describes an investigation into the effect of the addition of a polar co-solvent on the characteristics of an extract produced from cannabis plant material (G5 chemovar) using liquid CO2 extraction, and illustrates the difference in selectivity obtained using sub 40 critical vs super-critical CO2 extraction.
- 43 Experimental Detail.
Extraction experiments were carried out using a 1 litre 5 capacity C02 extraction apparatus. Food grade CO2 and BP grade absolute ethanol were employed as solvents.
A batch of G5 cannabis (a high CBD chemovar) was used.
The CBD content was 1.3% w/w after decarboxylation. Analysis of 10 the cannabinoid content of the extracts was carried out by HPLC.
Results and Discussion.
The data relating to the composition of the final extract 15 obtained after a hour extraction time under the specified conditions is presented below in Table 13: Table 13: Composition and Yield Data for Extracts Produced under Different Extraction Conditions.
SO SAMPLE EXTRACTION % W/W %CBD % RECOVERY
CONDITIONS EXTRACT (w/w) OF CBD AC470 lOoC/60 BAR 8.4% 63.6% 72.9% AC471 400C/100 BAR 10.7% 54.4% 79.5%
AC472 90C/100 BAR 10.3! 69.6% 91.0%
+ 2% ETHANOL
The recovery efficiency is based on the CBD available in decarboxylated plant material charged to the vessel for each extraction. 35 ':he results illustrate that changing the extraction -cnditions from sub-critical to super-critical increases the solvating power of the CON and results in a higher recovery of the available CBD. However, the supercritical CO2 can now solubilise a wider range of compounds and the extraction of 40 these additional compound has the effect of diluting the
- 44 concentration of CBD in the extract to such an extent that it is now lower than that obtained for the sub-critical extraction.
Consequently, the marginal additional recovery of available CBD from the raw material would not outweigh this disadvantage and 5 demonstrates the use of supercritical conditions is not desirable. The addition of 2% w/w absolute ethanol to supercritical CO, as a modifier increases the recovery of the available CBD to 10 >90%. Presumably the relatively polar cannabinoid is more soluble in the extract of increased polarity.
Interestingly, the concentration of CBD in the extract is increased slightly by the addition of polar modifier. This 15 would seem to indicate that the co-extractable non-cannabinoid material present in the plant material is less polar than the target cannabinoid and hence the extraction of this material (the "ballast") is deselected when polarity is increased.
Thus, extraction of cannabis plant material with supercritical 20 C02 -t 2t w/w ethanol provides an increase in recovery of the target active with no attendant penalty of loss of selectivity.
In summary:
25 1. A switch from sub-critical to super-critical conditions produces little advantage in terms of overall recovery of cannabinoid from the raw material but does result in the disadvantage of reducing the active content of the extract.
30 2. The addition of 2% absolute ethanol modifier to supercritical CO2 results in a significant improvement in the recovery of cannabinoid from the raw material with no penalty of dilution of active content by coextracted material.

Claims (1)

  1. - 45 Claims: 1. A method of extracting cannablnoids from plant material
    comprising a decarboxylation step, an extraction with 5 liquid carbon dioxide (CO2), and a step to reduce the proportion of non-target materials in the extract, characterized in that the extraction with liquid CO2 is conducted under sub-critical v-ditions at temperature in the range of from 5 to 15 C and a pressure in the range of from 50 to 70 bar.
    2. A method as claimed in claim 1 wherein the decarboxylation step is carried out after extraction with liquid CO 15 3. A method as claimed in claim 1 wherein the decarboxylation step is carried out prior to extraction with liquid CO2.
    4. A method as claimed in any one of claims 1 to 3 20 wherein the temperature is in the range of from 8 to 12 C.
    5. A method as claimed in claim 4 wherein the temperature is substantially 10 C.
    25 6. A method as claimed in any of the preceding claims wherein the pressure is in the range of from 55 to 65 bar.
    7. A method as claimed in claim 6 wherein the pressure is substantially 60 bar.
    8. A method as claimed in any of the preceding claims wherein the CO2 has a mass flow in the range of lOOO-1500 Kg/h.
    9. A method as claimed in claim 8 wherein the CO2 has a 35 mass flow of substantially 1250 Kg/h.
    10. A method as claimed in any of the preceding claims wherein the extraction is run for up to lO hours.
    - 46 l 11. A method as claimed in claim 10 wherein the extraction is run for about 8 hours.
    5 12. A method as claimed in any of the preceding claims wherein the CO2 is removed by depressurisation and the recovered extract held at a temperature in the range from -15 C to -20 C.
    13. A method as claimed in any of the preceding claims 10 wherein the step to reduce the proportion of non-target materials in the extract is a precipitation with a C1-C5 alcohol, wherein the material to be treated is warmed to above room temperature before the C1-C5 alcohol is added.
    15 14. A method as claimed in claim 13 wherein the C1-C5 alcohol is ethanol.
    15. A method as claimed in claim 13 or claim 14 wherein the extract is warmed to a temperature in the range from 36 C to 20 44 C.
    16. A method as claimed in claim 15 wherein the extract is warmed to about 40 C.
    25 17. A method as claimed in any of claims 14 to 16 wherein the C1-C5 alcohol is added in an amount of from 3:1 to 1:1 C1-C5 alcohol vol to weight of the material to be treated.
    18. A method as claimed in claim 11 wherein the C1-C5 30 alcohol is added in an amount of about 2:1 C1-C5 alcohol vol to weight of the material to be treated.
    19. A method as claimed in any of claims 13-18 wherein the solution resulting from addition of C1-C5 alcohol to the 35 material to be treated is chilled and insoluble materials; allowed to precipitate out.
    20, A method as claimed in any of claim 19 wherein the
    - 97 solution resulting from addition of C1-C5 alcohol to the material to be treated is chilled to a temperature in the range from -15 C to -25 C.
    5 21. A method as claimed in claim 19 or claim 20 wherein the solution resulting from addition of Cl-CS alcohol to the material to be treated is chilled for up to 52 hours.
    22. A method as claimed in any of claims 19 to 21 10 wherein the precipitate of insoluble materials is removed by filtration. 23. A method as claimed in claim 22 wherein filtration is through a 20pm membrane.
    24. A method as claimed in any of claims 13-23 further comprising a multistep evaporation under reduced pressure.
    25. A method as claimed in claim 24 wherein first C1-CS 20 alcohol is removed and then water is removed.
    26. A method as claimed in claimed in claim 25 wherein C1-C5 alcohol is removed by heating to a temperature in the range of 58-62aC to give a vapour temperature in the range of 25 38-42 C under a vacuum in the range of 168-172 mbar until there is little or no visible condensate.
    27. A method as claimed in claimed in claim 25 or claim 26 wherein water is additionally removed by a stepwise reduction 30 of the vacuum in stages to about 50 mbar 28. A method as claimed in any of claims 3 to 27 wherein the decarboxylation step is carried out prior to extraction with liquid CO2 and is conducted by heating the plant material to 35 temperatures and for times which ensure at least 9S% conversion of the acid cannabinoids to their neutral form whilst ensuring thermal degradation of THC to CON is less than 10.
    - 48 .. 29. A method as claimed in claim 28 in which a multi step heating process is conducted in which the plant material i s: i) heated to a first temperature for a first time period to 5 evaporate off retained water and allow for uniform heating of the plant material; and ii) the temperature is increased to a second temperature for a second time period until at least 95% conversion of the acid to cannabinoids to their neutral form has occurred.
    30. A method as claimed in claim 29 where the first step is conducted at a temperature in the range of 100 C to 110 C for 10-20 min. 31. A method as claimed in claim 30 wherein the first temperature is about 105 C and the first time period is about 15 minutes. 20 32. A method as claimed in any of claims 28-31 wherein the plant material has a high CBD content, the second temperature is in the range from llSDC to 125 C, preferably 120 C and the second time period is in the range from 45 minutes to 75 minutes, preferably about 60 minutes.
    33. A method as claimed in any of claims 28-31 wherein the plant material has a high CBD content the second temperature is in the range from 135 C to 145 C, preferably 140 C and the second time period is in the range from 15 to 45 minutes, 30 preferably about 30 minutes.
    39. A method as claimed in any of claims 28-31 wherein the plant material has a high CBD content, the second temperature is in the range from 140 C to 150 C, preferably 35 about 145 C and the second time period is in the range from 55-90 minutes.
    35. A method as claimed in any of claims 2B-31 wherein
    . - 49 -
    the plant material has a high THC content, the second temperature is in the range from 115 C to 125 C, preferably about 120 C, and the second time period is in the range from 45 minutes to 75 minutes, preferably about 60 minutes.
    36. A method as claimed in any of claims 28 to 31 wherein the plant material has a high THC content, the second temperature is from 100 C to 110 C, preferably about 105@C, and the second time period is in the range of 60 to 120 minutes.
    37. A method as claimed in any of claims 28 to 31 wherein the plant material has a high THC content, the second temperature is in the range from 140 C to 150 C, preferably about 145 C, and the second time period is in the range of 45 to 15 55 minutes.
    38. A method as claimed in any of claims 28-37 wherein the decarboxylation step is conducted at temperatures and for times which ensure at least 97% conversion of the acid 20 cannabinoids to their neutral form whilst ensuring thermal degradation of THC to CON is less than 5%.
    39. A method as claimed in any of the preceding claims wherein the plant material is ground, milled or otherwise 25 processed to less than 2mm.
    JO. A method as claimed in claim 39 wherein the particle size is greater than 1 mm.
    30 41. A method as claimed in any of claims 1-40 further comprising the step of treating an extract derived from the plant material with activated charcoal.
    42. A method as claimed in claim 41 wherein the extract 35 derived from the plant material is dissolved in an alcoholic solution. 93. A method as claimed in claim 42 wherein the
    - 50 alcoholic solution is an ethanolic solution.
    44. A method as claimed in claim 43 wherein treatment with activated charcoal follows an ethanolic precipitation step.
    45. A method of extracting cannabinoids from plant material comprising an extraction with liquid CO2, characterized in that an organic modifier or polar solvent is added to the carbon dioxide.
    46. A method as claimed in claim 45 in which the modifier or polar solvent is added in an amount of up to 10% by weight. 15 97. A method as claimed in claim 45 or 46 wherein the modifier or polar solvent is ethanol.
    48. A method as claimed in any of claims 3 to 27 wherein the plant material is agitated.
    49. A method as claimed in any of claims 3 to 27 wherein the plant material has a water content of from 8-12%.
    50. A botanical drug substance obtainable from botanical 25 raw material from a high THC containing cannabis plant having a THC content, wherein said botanical drug substance is an extract derived from the high THC cannabis plant comprising at least 50% THC w/w of extract, no more than 5% CBD as %w/w of the THC content, and no more than 5% cannabinoids other than THC and CBD 30 as %w/w of the THC content.
    51. A botanical drug substance obtainable from botanical raw material from a high CBD containing cannabis plant having a CBD content, wherein said botanical drug substance is an extract 35 derived from the high CBD cannabis plant comprising 50% CBD w/w of extract, no more than 7.5% THC as w/w of the CBD content, and no more than 5% cannabinoids other than CBD and THC as %w/w of the CBD content.
    - 51 ' J 52. A botanical drug substance as claimed in claim 50 or claim 51 comprising no more than 4ppb aflatoxin.
    5 53. A botanical drug substance as claimed in claim 50 or claim 51 comprising no more than 20ppm total heavy metals.
    54. A botanical drug substance as claimed in claim 50 or claim 51 comprising no more than 15% w/w residual solvents.
    55. A botanical drug substance as claimed in claim 54 wherein the residual solvent is ethanol.
    56. A botanical drug substance as claimed in claim 50 or 15 claim 51 comprising no more than 1Os ctu/g TVC, no more than 104 cfu/g fungi, no more than 103 cfu/g enterobacteria and other non gram negative organisms, and no detectable E. cold, Salmonella or S. aureus.
    20 57. A botanical drug substance obtained from cannabis comprising at least 60% cannabinoids, of which at least 90% is THC, about 1.5% is CBD and the remainder comprises other minor cannabinoids. 25 58. A botanical drug substance obtained from cannabis comprising at least 60% cannabinoids of which at least 85% is COD, about 3% is THC and the remainder comprises other minor cannabinoids. 30 59. A botanical drug substance resulting from the mixing of a botanical drug substance as claimed in claim 57 and 58.
    60. A method of making a pharmaceutical composition comprising, as an active agent, a botanical drug substance which 35 an extract from at least one cannabis plant, which method comprises preparing a botanical drug substance containing cannabinoids from at least one cannabis plant using an extraction method according to any one of claims 1 to 48, and
    - 52 -
    formulating the botanical drug substance with one or more pharmaceutically acceptable diluents, carriers or excipients to produce a pharmaceutical composition.
GB0218901A 2002-08-14 2002-08-14 Improvements in the extraction of pharmaceutically active components from plant materials Expired - Lifetime GB2391865B (en)

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SI200332204T SI1536810T1 (en) 2002-08-14 2003-08-14 Extraction of pharmaceutically active cannabinoids from plant materials
DK03787897.2T DK1536810T3 (en) 2002-08-14 2003-08-14 EXTRACTION OF PHARMACEUTICAL ACTIVE CANNABINOIDS FROM PLANT MATERIALS
KR1020057002527A KR101113162B1 (en) 2002-08-14 2003-08-14 Improvements in the extraction of pharmaceutically active components from plant materials
AU2003253002A AU2003253002B2 (en) 2002-08-14 2003-08-14 Extraction of pharmaceutically active cannabinoids from plant materials
DE10337458A DE10337458B4 (en) 2002-08-14 2003-08-14 Improvements in the extraction of pharmaceutically active components from plant materials
DK10180464.9T DK2311475T3 (en) 2002-08-14 2003-08-14 Extraction of pharmaceutically active cannabinoids FROM PLANT MATERIALS
PT03787897T PT1536810E (en) 2002-08-14 2003-08-14 Extraction of pharmaceutically active cannabinoids from plant materials
PT101804649T PT2311475T (en) 2002-08-14 2003-08-14 Extraction of pharmaceutically active cannabinoids from plant materials
PCT/GB2003/003566 WO2004016277A2 (en) 2002-08-14 2003-08-14 Extraction of pharmaceutically active cannabinoids from plant materials
ES10180464.9T ES2592531T3 (en) 2002-08-14 2003-08-14 Extraction of pharmaceutically active cannabinoids from plant materials
CA2994322A CA2994322A1 (en) 2002-08-14 2003-08-14 Botanical drug substances comprising various proportions of thc and cbd
EP03787897A EP1536810B1 (en) 2002-08-14 2003-08-14 Extraction of pharmaceutically active cannabinoids from plant materials
MXPA05001621A MXPA05001621A (en) 2002-08-14 2003-08-14 Improvements in the extraction of pharmaceutically active components from plant materials.
PL375357A PL205945B1 (en) 2002-08-14 2003-08-14 Improved EXTRACTION OF PHARMACEUTICALLY ACTIVE CANNABINOIDS FROM PLANT MATERIALS
CA2823474A CA2823474A1 (en) 2002-08-14 2003-08-14 Botanical drug substances comprising various proportions of thc and cbd
PL388837A PL226646B1 (en) 2002-08-14 2003-08-14 Botanical drug substance
ES03787897T ES2392510T3 (en) 2002-08-14 2003-08-14 Extraction of pharmaceutically active cannabinoids from plant materials
CN038242117A CN1691954B (en) 2002-08-14 2003-08-14 Extraction of pharmaceutically active cannabinoids from plant materials
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