Extraction and purification of cannabinoid compounds

Abstract

Disclosed are effective methods for activating, washing, specifically extracting and purifying cannabinoids from Cannabis plant tissues using heat activation, washing impurities away with a polar solvent, optionally modified with an organic acid, base, surfactant or inorganic salt, extracting the activated non-polar cannabinoids with a potable selective solvent such as ethanol. The extracted active ingredients may be purified by chromatography and detected and quantified by mass spectrometry with external or isotopic or otherwise labelled standards.

Claims

1. A method of extracting a cannabinoid from a Cannabis plant tissue comprising the steps: a) a heating step of heating the Cannabis plant tissue to convert carboxylated forms of the cannabinoid to a decarboxylated activated non-polar form of the cannabinoid in an activated Cannabis plant tissue; b) at least one washing step of washing the decarboxylated activated non-polar form of the cannabinoid or the activated Cannabis plant tissue with a polar solvent, wherein the polar solvent is polar and comprises water, wherein the polar solvent is removed as waste and thus selectively removes polar components that are soluble in the polar solvent, leaving the decarboxylated activated non-polar form of the cannabinoid; and c) an extraction step of selectively extracting the decarboxylated activated non-polar form of the cannabinoid using a potable selective solvent, wherein the potable selective solvent is an organic non-polar solvent, wherein the potable selective solvent comprises 80% ethanol in water, and wherein the extraction step is performed at a refrigerated temperature that is above a freezing temperature and below a flashpoint temperature of the potable selective solvent; and a vacuum drying step, after the extraction step, of drying the decarboxylated activated non-polar form of the cannabinoid under a vacuum at the refrigerated temperature to make an intermediate resin; wherein the extraction step is performed after the heating step; wherein the washing step is performed after the extraction step; and wherein, after the vacuum drying step, the intermediate resin is washed in the polar solvent.

2. The method of claim 1, wherein before the washing step, the Cannabis plant tissue is solid or has been processed to a powder or suspension.

3. The method of claim 1, wherein after the extraction step, the extracted cannabinoids is separated using chromatography including ion exchange or reverse phase.

4. The method of claim 3, wherein the separated cannabinoids is identified and/or quantified using mass spectrometry (MS).

5. The method of claim 1 wherein the polar solvent further comprises water modified by a salt, a non-ionic non-polymeric detergent or a bile salt, a sodium deoxycholate, a potable buffer, a potable phosphate or carbonate buffer, an organic acid, an acetic acid or formic acid, ammonia, ammonium hydroxide, methylamine trimethylamine, or ethanol, provided the ethanol is less than 40% (v:v).

6. The method of claim 5 wherein the polar solvent comprises less than 0.5% acetic acid in water by volume.

7. The method of claim 5 wherein the polar solvent comprises 40% ethanol in water by volume.

8. The method of claim 1 wherein the washing step is performed multiple times.

9. The method of claim 8 wherein the washing step is performed multiple times with a first polar solvent, followed by multiple washes with a second polar solvent, different from the first.

10. The method of claim 9 wherein the first polar solvent comprises water modified by an organic acid and the second polar solvent comprises ethanol.

11. The method of claim 8 wherein the washing step is performed at a temperature less than about 5° C.

12. The method of claim 1 wherein the refrigerated temperature is less than about 5° C.

13. The method of claim 12 wherein the refrigerated temperature is less than about 0° C.

14. The method of claim 5 wherein the polar solvent comprises less than 5.0% acetic acid in water by volume.

15. The method of claim 14 wherein the polar solvent comprises less than 1.0% acetic acid in water by volume.

16. The method of claim 10 wherein the first polar solvent comprises said water modified by an acetic acid.

17. The method of claim 10 wherein the second polar solvent comprises 40% ethanol in water.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an illustration of a scheme to activate, wash, selectively extract, purify, identify and quantify the cannabinoid compounds.

(2) FIG. 2A. The separation and detection of CBD, and CBDa by isocratic HPLC in 70% AcN 0.1% formic acid of 100% Ethanol extract prior by 300 Angstrom 5 micron C18 porous resin to LC-ESI-MS (n=1). Note the porous resin does not resolve CBD from THC.

(3) FIG. 2B. The separation and detection of THC and THCa by isocratic HPLC in 70% AcN 0.1% formic acid of 100% Ethanol extract prior by 300 Angstrom 5 micron C18 porous resin to LC-ESI-MS (n=1). Note the porous resin does not resolve CBD from THC.

(4) FIG. 3. The separation and detection of CBD in hemp A on a 300 Angstrom 5 micron C18 porous resin by LC-ESI-MS with a isocratic HPLC in 70% AcN 0.1% formic acid of HA1, HE8, and HE1 extract (n=5). Spectra depicts (A) 3× blank (B) external CBD standard curve from 0-200 uM (C) detection of CBD (m/z 315) in hemp A HA1 extract, (D) HE8 extract (E) HE1 extract, (F) mix of HE8 and HE1 extract, (C1) HA1 extract spiked with CBD-D3 (m/z 318), (D1) HE8 extract spiked with CBD-D3, (E1) HE1 extract spiked with CBD-D3 and (F1) mix of HE8 and HE1 extract spiked with CBD-D3. (HA1: sampled heated extracted in 100% can; HE8: sample heated extracted in 80% EtOH; HE1: sample heated extracted in 100% EtOH).

(5) FIG. 4A. The separation and detection of CBD alone by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1), on a 6 cm column, using a Kinetex™ coreshell resin.

(6) FIG. 4B. The separation and detection of THC alone by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1), on a 6 cm column, using a Kinetex™ coreshell resin.

(7) FIG. 4C. The separation and detection of CBD and THC by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1), on a 6 cm column, using a Kinetex™ coreshell resin.

(8) FIG. 4D. The separation and detection of CBD and THC by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1), on a 15 cm column, using a Kinetex™ coreshell resin.

(9) FIG. 5A. The separation and detection of CBD, CBDa, THC and THCa by gradient HPLC and LC-ESI-MS (n=1), for Sample 1 spiked with CBD-D3Gradients—Sample was diluted in B buffer (65% AcN, 5% FA) with gradient 0 min at 70%, 10 min linear gradient to 80%, held for 5 min at 80% and equilibrate at 70% (base peak).

(10) FIG. 5B. The separation and detection of CBD, CBDa, THC and THCa by gradient HPLC and LC-ESI-MS (n=1) for Sample 2 spiked with CBD-D3. Gradients—Sample was diluted in B buffer (65% AcN, 5% FA) with gradient 0 min at 70%, 10 min linear gradient to 80%, held for 5 min at 80% and equilibrate at 70% (base peak).

(11) FIG. 5C. The separation and detection of CBD, CBDa, THC and THCa by gradient HPLC and LC-ESI-MS (n=1) for CBD and THC reference standards. Gradients—Sample was diluted in B buffer (65% AcN, 5% FA) with gradient 0 min at 70%, 10 min linear gradient to 80%, held for 5 min at 80% and equilibrate at 70% (base peak).

(12) FIG. 5D. The separation and detection of CBD, CBDa, THC and THCa by gradient HPLC and LC-ESI-MS (n=1) for CBD and THC reference standards. Gradients—Sample was diluted in B buffer (65% AcN, 5% FA) with gradient 0 min at 70%, 10 min linear gradient to 80%, held for 5 min at 80% and equilibrate at 70% (base peak).

(13) FIG. 6A. The separation and detection of CBD, CBDa, THC and THCa by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1) on a 15 cm column over Kinetex™ coreshell resin for CBD and THC reference standard.

(14) FIG. 6B. The separation and detection of CBD, CBDa, THC and THCa by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1) on a 15 cm column over Kinetex™ coreshell resin for CBD alone.

(15) FIG. 6C. The separation and detection of CBD, CBDa, THC and THCa by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1) on a 15 cm column over Kinetex™ coreshell resin for THC alone.

(16) FIG. 6D. The separation and detection of CBD, CBDa, THC and THCa by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1) on a 15 cm column over Kinetex™ coreshell resin for Sample A spiked with CBD-D3.

(17) FIG. 6E. The separation and detection of CBD, CBDa, THC and THCa by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1) on a 15 cm column over Kinetex™ coreshell resin for Sample B spiked with THC-D3.

(18) FIG. 7A. Decarboxylation of CBDa at different temperatures for 0.1 g of hemp sample 1 heated to the appropriate temperature for 1 hour and extracted 3× with 100% Ethanol prior to LC-ESI-MS (n=3).

(19) FIG. 7B. Decarboxylation of CBDa at different temperatures for 0.1 g of hemp sample 2 heated to the appropriate temperature for 1 hour and extracted with 100% Ethanol prior to LC-ESI-MS (n=1).

(20) FIG. 7C. Decarboxylation of CBDa at different temperatures for 0.1 g of hemp sample 2 heated to the appropriate temperature for 1 hour and extracted with 100% Ethanol prior to LC-ESI-MS (n=3).

(21) FIG. 8A. CBD external standard curve (n=2) from 50-5000 nM.

(22) FIG. 8B. Internal versus external CBD curve (n=2) from 50-5000 nM.

(23) FIG. 8C. Illustration spectra of the detection of CBD (m/z 315) in a hemp sample heated to 120° C. spiked with CBD-D3 (m/z 318) measured by isocratic separation over C18 resin.

(24) FIG. 9A. EtOH gradient extraction of CBD extracted in ethanol gradient from 0.1 g of hemp heated to 120° C. for 1 hour vs. no heating control (0 C), extracted in a sequential step gradient of increasing Ethanol and analyzed by LC-ESI-MS (n=3).

(25) FIG. 9B. EtOH gradient extraction of CBD and CBDa extracted from 0.1 g hemp in an ethanol gradient from the no heating control sample (0 C) and analyzed by LC-ESI-MS (n=3).

(26) FIG. 9C. EtOH gradient extraction of CBD and CBDa extracted from 0.1 g hemp in an ethanol gradient from a hemp sample heated to 120° C. for 1 hour and analyzed by LC-ESI-MS (n=3).

(27) FIG. 10. Effect of pH on the extraction of CBD from hemp in 80% Ethanol (n=3). 0.1 g of hemp was heated to 120° C. for 1 hour, washed 3× with H2O, 3× with 40% Ethanol followed by extraction in 80% Ethanol at various pH levels prior to analysis by LC-ESI-MS. Sample 1, 0.1% TFA in 80% EtOH pH>2 (not adjusted); Sample 2, 0.1% FA in 80% EtOH pH2 (not adjusted); Sample 3, 0.1% Acetic acid in 80% EtOH pH3 (not adjusted); Sample 4, 10 mM Citric acid in 80% EtOH pH4; Sample 5, 10 mM Citrate in 80% EtOH pH5; Sample 6, 10 mM Citrate in 80% EtOH pH6; Sample 7, 10 mM Tris in 80% EtOH pH7; Sample 8, 10 mM Tricine in 80% EtOH pH8; Sample 9, 0.1% Ethanolamine in 80% EtOH pH9; Sample 10, 0.1% Ethanolamine in 80% EtOH pH10; Sample 11, 0.1% Ammonia in 80% EtOH pH<10 (not adjusted); Sample 12, 80% EtOH in H2O (pH not adjusted).

(28) FIG. 11. Mass recovery after extraction with different solvents (n=3). A, 0.1 g Hemp was heated to 120° C. for 1 hour prior to extraction with various solvents. Mass yields after extraction with different solvents (n=3). A, 0.1 g Hemp was heated to 120° C. for 1 hour prior to extraction with various solvents (3 sequential extracts were pooled). Samples were dried to determine the mass extracted and re-dissolved for mass spectrometry analysis to measure CBD content.

(29) FIG. 12A. CBD yields from 5 sequential extractions for 0.1 g hemp heated to 120° C. for 1 hour and extracted in 5× H2O.

(30) FIG. 12B. CBD yields from 5 sequential extractions for 0.1 g hemp heated to 120° C. for 1 hour and extracted in 5× Acetonitrile without pre-washing with H2O.

(31) FIG. 12C. CBD yields from 5 sequential extractions for 0.1 g hemp heated to 120° C. for 1 hour and extracted in 5× Ethanol without pre-washing with H2O.

(32) FIG. 12D. CBD yields from 5 sequential extractions for 0.1 g hemp heated to 120° C. for 1 hour and extracted in 5× Acetonitrile pre-washed with 5× H2O (n=3).

(33) FIG. 12E. yields from 5 sequential extractions for 0.1 g hemp heated to 120° C. for 1 hour and extracted in 5× Ethanol pre-washed with 5× H2O (n=3).

(34) FIG. 13A. Optimizing binding conditions for CBD using ion exchange chromatography (n=3). 0.1 g of hemp was heated to 120° C. and extracted 3× in 100% ethanol. Extracts of 0.5 g total hemp per replicate were pooled and diluted with H2O to the appropriate ethanol concentrations. Samples were loaded at 100% ethanol and decreasing to 10% ethanol onto the DEAE resin. The Flow Throughs (FT) were collected and analyzed by LC-ESI-MS.

(35) FIG. 13B. Optimizing binding conditions for CBD using ion exchange chromatography (n=3). 0.1 g of hemp was heated to 120° C. and extracted 3× in 100% ethanol. Extracts of 0.5 g total hemp per replicate were pooled and diluted with H2O to the appropriate ethanol concentrations. Samples were loaded at 100% ethanol and decreasing to 10% ethanol onto the CMS resin. The Flow Throughs (FT) were collected and analyzed by LC-ESI-MS.

(36) FIG. 13C. Optimizing binding conditions for CBD using ion exchange chromatography (n=3). 0.1 g of hemp was heated to 120° C. and extracted 3× in 100% ethanol. Extracts of 0.5 g total hemp per replicate were pooled and diluted with H2O to the appropriate ethanol concentrations. Samples were loaded at 100% ethanol and decreasing to 10% ethanol onto the HiQ resin. The Flow Throughs (FT) were collected and analyzed by LC-ESI-MS.

(37) FIG. 13D. Optimizing binding conditions for CBD using ion exchange chromatography (n=3). 0.1 g of hemp was heated to 120° C. and extracted 3× in 100% ethanol. Extracts of 0.5 g total hemp per replicate were pooled and diluted with H2O to the appropriate ethanol concentrations. Samples were loaded at 100% ethanol and decreasing to 10% ethanol onto the HiS resin. The Flow Throughs (FT) were collected and analyzed by LC-ESI-MS.

(38) FIG. 14A. Elution curves in Ethanol for HiQ columns (n=3). ˜7.5 mg CBD was extracted from 0.5 g hemp in 100% Ethanol, diluted to 20% ethanol and loaded onto a ˜100 ul HiQ column. The column was washed with loading solvent prior to elution with increasing amounts of Ethanol (25, 30, 32.5, 35, 37.5, 40, 42.5, 45, 47.5, 50, 55 and 60%). Up to ˜50%, the fractions are observed to be clear. Above 50%, the elutions become green. Fractions were collected and analyzed by LC-MS.

(39) FIG. 14B. Elution curves in Acetonitrile for HiQ columns (n=3). ˜7.5 mg CBD was extracted from 0.5 g hemp in 100% Acetonitrile, diluted to 20% acetonitrile and loaded onto a ˜100 ul HiQ column. The column was washed with loading solvent prior to elution with increasing amounts of Acetonitrile (25, 30, 32.5, 35, 37.5, 40, 42.5, 45, 47.5, 50, 55 and 60%). Up to ˜35%, the fractions are observed to be clear. Above 35%, the elutions become green (elutions separate in 2 distinct layers, one clear and one green). Fractions were collected and analyzed by LC-MS.

(40) FIG. 15. CBD external standard curve 50-50,000 nM (n=2) measured by LC-ESI-MS/MS using isocratic separation over C18 resin.

(41) FIG. 16. The wash of intermediate resin from cannabis sample A. A 0.1 g aliquot of cannabis sample A was washed heated to 120° C. for 1 hour, extracted in ethanol and dried under vacuum to make a intermediate resin. The water soluble components of the resin were washed in water or water modified with organic acid, ethanol, or salt.

(42) FIG. 17. The wash of intermediate resin from cannabis sample B. A 0.1 g aliquot of cannabis sample A was washed heated to 120° C. for 1 hour, extracted in ethanol and dried under vacuum to make an intermediate resin. The water soluble components of the resin were washed in water, water with 0.5% acetic acid (v:v), ethanol, or salt.

(43) FIG. 18. The extraction of intermediate resin from cannabis sample A. A 0.1 g aliquot of cannabis sample A was washed heated to 120° C. for 1 hour, extracted in ethanol and dried under vacuum to make a intermediate resin. The water soluble components of the resin were washed in water with 0.5% acetic acid (v:v) and extracted with 1 ml of the solvent shown.

(44) FIG. 19. The extraction of intermediate resin from cannabis sample B. A 0.1 g aliquot of cannabis sample B was washed heated to 120° C. for 1 hour, extracted in ethanol and dried under vacuum to make a intermediate resin. The water soluble components of the resin were washed in water with 0.5% acetic acid (v:v) and extracted with 1 ml of the solvent shown.

DETAILED DESCRIPTION

(45) The present invention comprises methods of selectively extracting and purifying cannabinoids from plant tissue, such as cannabinoid plant tissue.

(46) Cannabinoids are compounds which act on or modulate cannabinoid receptors in cells, which can alter neurotransmitter release in the brain. Cannabinoids were originally found in Cannabis saliva L., the origin of marijuana and hashish. Marijuana or its components have been reported in the scientific literature to alleviate the symptoms of a broad range of conditions including multiple sclerosis and forms of muscular spasm, including uterine and bowel cramps; movement disorders; pain, including migraine headache; glaucoma, asthma, inflammation, insomnia, and high blood pressure. There may also be utility for cannabinoids as an oxytoxic, anxiolytic, anti-convulsive, anti-depressant and/or anti-psychotic agent, anti-cancer agent, or an appetite stimulant.

(47) Many chemically related compounds, collectively classified as cannabinoids, have been isolated from Cannabis plants. The cannabinoids usually divided in the groups of classical cannabinoids, non-classical cannabinoids, aminoalkylindole derivatives and eicosanoids. Classical cannabinoids such as THC or CBD are isolated from Cannabis sativa L., or they can comprise synthetic analogs of these compounds. Non-classical cannabinoids may comprise bi- or tricyclic analogs of tetrahydrocannabinol (THC), while aminoalkylindoles form a group which differs structurally substantially from classical and non-classical cannabinoids.

(48) In various embodiments, cannabinoids can include, but are not limited to, cannabinoid compounds that may naturally occur in different combinations and relative quantities in the plant tissues of various species, subspecies, hybrids, strains, chemovars, and other genetic variants of the genus Cannabis, including material that may variously be classified as “marijuana” and “hemp” in accordance with various legal or technical definitions and standards.

(49) An exemplary cannabinoid comprises THC, having the formula (I):

(50) ##STR00001##
which includes delta-9-tetrahydrocannabinol (D9THC), acknowledged to be the main psychoactive compound in marijuana. Another exemplary cannabinoid is cannabidiol (CBD) IUPAC: 2-[(1R,6R)-6-isopropenyl-3-methylcyclohex-2-en-1-yl]-5-pentylbenzene-1,3-diol, having the formula (II):

(51) ##STR00002##
Although CBD is not known to have the psychotropic effects of THC, it is still considered to have a wide scope of potential therapeutic applications. CBD may be derived from industrial hemp which has negligible amounts of THC, and may be legally grown and consumed in Canada and the United States.

(52) Cannabinoid compounds may also include various other cannibinoids such as tetrahydrocannabinolic acid (THCA), delta-8-tetrahydrocannabinol (D8THC), cannabidiolic acid (CBDA), cannabinol (CBN), cannabinolic acid (CBNA), tetrahydrocannabinovarin (THCV), tetrahydrocannabinovarinic acid (THCVA), cannabidivarin (CBDV), cannabidivarin acid (CBDVA), cannabigerol (CBG), cannabigerolic acid (CBGA), cannabichromene (CBC), cannabichromenic acid (CBCA), cannabinodiol (CBND), and cannabinodiolic acid (CBNDA).

(53) The term “selective” as used herein in reference to a solvent, a solid phase or chromatography system of a solvent or solid phase, is one that selectively extracts or purifies a target substance or compound, such as a cannabinoid, with greater specificity relative to another different substance or compound. In some embodiments, the selective system purifies the target substance or compound by at least 2 fold, 3 fold, or 5 fold.

(54) FIG. 1 is an illustration of a general scheme to activate, wash, selectively extract, purify, identify and quantify cannabinoid compounds from cannabis plant tissue. Accordingly, in one aspect, the invention may comprise a method of selectively extracting and purifying a cannabinoid from plant tissue comprising the steps of: a. preparing plant tissue in fresh or dried form; b. heating the tissue to decarboxylate cannabinoid compounds; c. optionally, extracting the tissue with a selective solvent to produce an intermediate resin; d. washing the tissue or resin with an polar solvent to selectively remove compounds soluble in the polar solvent while leaving decarboxylated cannabinoid compounds; e. selectively extracting the cannabinoid from the plant tissue using a selective solvent to produce a cannabinoid extract.

(55) Preferably, the cannabinoids from the extract can be purified by precipitation and/or partition chromatography drying. Finally, the cannabinoids can be detected by liquid chromatography electrospray or atmospheric pressure ionization and tandem mass spectrometry (MS/MS).

(56) The methods disclosed herein may be performed on finely divided plant tissue, such as fresh or dried tissue which has been cut, chopped, ground, mashed or otherwise processed to reduce particle size. The method may also be performed in solution in the absence of a solid phase, wherein the target substance is not in the solid phase but in a colloidal suspension or fine powder in water or otherwise suspended or emulsified in a liquid phase.

(57) Preferably, the polar solvent comprises purified water, or water mixed with alcohol such as ethanol, preferably less than about 40% ethanol (v:v), or acetic acid, preferably less than about 5% acetic acid (v:v). It is preferred that all components are potable. As used herein, a potable component is one that is classified as “Generally Regarded as Safe” or “GRAS” by the United States FDA.

(58) Polar solvents have large dipole moments (“partial charges”); that is they contain bonds between atoms with very different electronegativities, such as oxygen and hydrogen. Non polar solvents contain bonds between atoms with similar electronegativities, such as carbon and hydrogen. Bonds between atoms with similar electronegativities will lack partial charges. In one embodiment, the polar solvent is one with a dielectric constant greater than about 5.0 at 20° C., preferably greater than about 20, and more preferably greater than about 50.

(59) In some embodiments, the washing polar solvent comprises a non-ionic, non-polymeric detergent or a bile acid detergent, such as sodium deoxycholate. In an embodiment, the wash solvent contains a potable buffer such as phosphate or carbonate buffer, such as Na.sub.2CO.sub.3 or NaHCO.sub.3, an organic acid, such as acetic acid or formic acid, ammonia, ammonium hydroxide, methylamine trimethylamine or the like.

(60) It is preferred that the polar solvent wash take place at a reduced temperature, preferably below about 5° C., and more preferably below about 00° C., but obviously above the freezing temperature of the solvent.

(61) In some embodiments, multiple washes with different polar solvents is preferred. For example, a first wash in 0.5% acetic acid (v:v) may be repeated up to three times, followed by a second wash in 40% ethanol (v:v), repeated up to three times. Without restriction to a theory, it is believed that an initial wash in a weak organic acid may protonate water-soluble impurities, facilitating their dissolution in the aqueous phase. The subsequent washes in ethanol/water selectively removes additional polar impurities.

(62) The selective solvent is one which selectively extracts the activated (decarboxylated) cannabinoid, and may be polar or non-polar. Preferably, the extract solvent comprises ethanol, or ethanol mixed in water, preferably greater than about 40% ethanol (v:v), more preferably 80% ethanol. Potable ethanol is intended for human consumption and contains no unacceptable residues of harmful solvents.

(63) In some embodiments, the cannabinoid is selectively extracted with about 80% ethanol at a refrigerated temperature, preferably between about −80° C. and about 5° C., and more preferably between about −20° C. and 0° C. In view of the teachings and disclosures herein, it should be appreciated that the refrigerated extraction temperature will be higher than the 80% ethanol's freezing temperature and lower than its flashpoint temperature.

(64) Extraction may be followed by precipitation or drying to recover the desired cannabinoid compounds.

(65) The extracted compounds may be purified by liquid partition chromatography as monitored by electrospray ionization or atmospheric pressure chemical ionization and tandem mass spectrometry (LC-ESI-MS/MS) is more sensitive and definitive than colorimetric, fluorescent, flame ionization, or electron capture detection and permits standards labelled with isotopes or isobaric tags. Since mass spectrometers can separate and analyze many analytes simultaneously using the methods described herein, it can allow identification and quantification of many different cannabinoids at the same time to levels far below that which is possible by direct mass spectrometric analysis.

(66) While the present application has been described with reference to what are presently considered to be preferred examples, it is to be understood that the application is not limited to the disclosed examples. To the contrary, the application is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Examples

(67) The following examples are intended to illustrate specific embodiments of the claimed invention, and not be limiting in any way.

(68) Mass Recovery

(69) 0.1 g Hemp was heated to 120° C. for 1 hour prior to extraction with various solvents: ethanol, methanol, acetonitrile, isopropyl alcohol, ethyl acetate and acetone. 3 sequential extracts were pooled. Samples were dried to determine the mass extracted and redissolved for mass spectrometry analysis to measure CBD content. Total CBD was set to 1.7082 mg/100 mg. The results are shown in Table 1 below

(70) TABLE-US-00001 TABLE I Mass yields after extraction with different solvents (n = 3). % mass recovery Extraction mass extracted (mg) CBD (mg) from total in % CBD of mass solvent from 100 mg hemp from 100 mg hemp tissue extracted EtOH 7.004692478 0.7931933 46.43282818 11.32 MeOH 6.772186616 0.8139417 47.64742232 12.02 AcN 3.839389904 0.9036164 52.8968976 23.54 IPA 5.506566586 0.7875847 46.10450387 14.30 Ethyl Acetate 5.569882112 0.9563186 55.9820377 17.17 Acetone 4.758931245 0.7973442 46.6758185 16.75 The first column—(((Tube+dried extract)−tube)*100 mg hemp)/actual weight of hemp (mg). The second column—STD curve equation used to find concentration of CBD. Then, CBD (mg)=(Mw×V(L)×M)×1000. Standardize to 100.00 mg hemp: ((CBD (mg)*100 mg)/actual hemp (mg) Mass recovery (3.sup.rd column)=(CBD(mg)/CBD Total (mg))*100% 4.sup.th column=(CBD (mg)/mass extract (mg))*100%

(71) The results are shown graphically in FIG. 11 and appear to indicate that the solvents are substantially similar in their ability to extract CBD.

(72) Effect of Drying and Pre-washing

(73) 0.1 g hemp was heated to 120° C. for 1 hour and extracted in 3× 100% ethanol extraction with no pre-wash and without drying the extract (results in Table IIA); or in 80% ethanol extraction pre-washed with 3× water, 3× 40% ethanol and extracted once in 500 ul 80% ethanol (results in Table IIB). Samples were detected on a LC-ESI-MS using a 300 Angstrom 5 micron C18 porous resin.

(74) TABLE-US-00002 TABLE IIA Effect of drying on the re-solubilization of CBD and THC from cannabis tissue (n = 3). CBD (mg)/100 mg tissue CBD (mg)/100 mg tissue Extracted with 3x 100% Extracted with 3x 100% Ethanol without pre- % recovery mass extracted (mg) from Ethanol without pre-washing, washing, extracts were from total in 100 mg tissue without drying extract dried to determine yield tissue % CBD of mass extracted rep1 6.858287815 1.058157929 1.122850101 65.7306445 16.3721636 rep2 6.960101951 1.113238091 1.176511817 68.87195354 16.90365781 rep3 7.001634043 1.106011877 1.187489191 69.51455927 16.96017221 AVG 6.940007936 1.092469299 1.162283703 68.03905244 16.74533121

(75) TABLE-US-00003 TABLE IIB Tissue extracted with 80% Ethanol was pre-washed with 3x water and 3x 40% ethanol and extracted 1x with 80% ethanol CBD (mg)/100 mg tissue CBD (mg)/100 mg tissue Extracted with 80% Extracted with 80% Ethanol Ethanol with pre-washing with pre-washing in water in water and 40% Ethanol, % recovery mass extracted (mg) from and 40% ethanol, without extracts were dried to from total in 100 mg tissue drying extract determine yield tissue % CBD of mass extracted rep1 1.415841584 0.537632812 0.531468885 31.11171503 37.53731288 rep2 1.411530815 0.59309931 0.521653691 30.53714231 36.95659249 rep3 1.580516899 0.591777471 0.460355469 26.94879899 29.12689318 AVG 1.469296433 0.574169864 0.504492682 29.53255211 34.54026618
Multiple Extracts

(76) CBD yields from 5 sequential extractions with and without pre-washing with water (n=3). 0.1 g hemp was heated to 120° C. for 1 hour and extracted in:

(77) A, 5× H2O without pre-washing;

(78) B, 5× Acetonitrile without pre-washing;

(79) C, 5× Ethanol without pre-washing;

(80) D, 5× Acetonitrile pre-washed with H2O;

(81) E, 5× Ethanol pre-washed with H2O.

(82) The mass yields and yield CBD of five fractions combined are shown in Table IIIA. The mass yields and yield CBD of the first three fractions combined are shown in Table IIIB. Samples were detected on a LC-ESI-MS using a 300 Angstrom 5 micron C18 porous resin. Mass is defined as the dry tissue product extracted.

(83) TABLE-US-00004 TABLE III The effect of multiple extracts of the yield and purity of CBD and THC from Cannabis tissue. A. Dried Mass % recovery % recovery 5 sequential hemp extract CBD from total from total % of mass % of extracts combined (mg) (mg) (mg) in tissue in tissue extracted extractable H2O 100 21.72245 0.00668 21.7224505 0.391161409 0.030761044 AcN 100 18.81004 0.851712338 18.81004126 49.85848141 4.527966344 EtOH 100 11.06295 0.88375334 11.06295119 51.73413315 7.988404947 AcN pre-washed w 5x H2O 100 6.30919 0.758266369 6.309190786 44.38823766 12.01844095 89.028459 EtOH pre-washed w 5x H2O 100 4.33586 0.762428385 4.335861815 44.63187836 17.58424086 86.271627 B. Dried Mass % recovery % recovery First 3 sequential hemp extract CBD from total from total % of mass % of extracts combined (mg) (mg) (mg) in tissue in tissue extracted extractable H2O 100 18.50383 0.00592 18.50383271 0.346333151 0.031973212 MN 100 15.95629 0.830843944 15.95629159 48.63686421 5.206999 EtOH 100 8.31385 0.854943702 8.313853682 50.04764262 10.28336239 AcN pre-washed w 5x H2O 100 4.96295 0.72285888 4.962954964 42.31551479 14.56509045 87.0029667 EtOH pre-washed w 5x H2O 100 3.85851 0.703263897 3.858510015 41.16844198 18.22630743 82.2585038
The results are shown graphically in FIGS. 12A-12E.
Effect of Pre-Wash with Salt, Acid or Base

(84) 0.1 g of hemp was heated to 120° C. and pre-washed 3× with PBS, PBS+600 mM NaCl, 0.5% acetic acid (Hac), 0.5% ammonia or H.sub.2O, followed by 3 washes of 40% Ethanol. CBD was then extracted with 3× 500 ul of 80% Ethanol and the three fractions were pooled. The samples pre-washed in H.sub.2O were extracted 1× with 1 ml of Ethanol.

(85) TABLE-US-00005 TABLE IV-A Effect of pre-washing with salt, acid or base on the extraction efficiency of CBD from hemp (n = 3). CBD Mass extract (mg) (mg) from from % recovery 0.100 g 0.100 g from total in % of mass Pre-wash hemp hemp tissue extracted PBS 3.9401649 0.76486 44.774197 19.40 PBS + 600 mM NaCl 10.7597825 0.67671 39.6142859 6.92 0.5% HAc 3.52848406 0.81832 47.9036073 23.34 0.5% Ammonia 4.15815607 0.76476 44.7686614 19.51 H2O 2.14577484 0.65554 38.3749606 30.54
In a separate experiment, samples were pre-washed in 3× water followed by 3 washes in 10%, 20%, 30% or 40% ethanol and extracted in 3×500 ul 80% ethanol. Fractions were pooled.

(86) TABLE-US-00006 TABLE IV-B Mass extract CBD (mg) % recovery % of (mg) from from 0.100 g from total in mass Pre-wash 0.100 g hemp hemp tissue extracted 10% EtOH 3.51704 0.55792 32.6601693 15.86335 20% EtOH 4.10537 0.5485614 32.1122937 13.36206 30% EtOH 4.10044 0.5997451 35.1085456 14.62637 40% EtOH 4.23101 0.5910847 34.6015711 13.97028

(87) FIGS. 2A and 2B shows the separation and detection of CBD, CBDa (FIG. 2A) THC and THCa (FIG. 2B) by isocratic HPLC in 70% AcN 0.1% formic acid, of a 100% Ethanol extract by 300 Angstrom 5 micron C18 porous resin to LC-ESI-MS (n=1). Note the porous resin does not resolve CBD from THC.

(88) FIG. 3 shows the separation and detection of CBD in hemp sample A on a 300 Angstrom 5 micron C18 porous resin by LC-ESI-MS with a isocratic HPLC in 70% AcN 0.1% formic acid. HA1 is a sample heated and extracted in 100% acetonitrile (AcN); HE8 is a sample heated and extracted in 80% EtOH; and HE1 is a sample heated and extracted in 100% EtOH. (n=5). Spectra depicts (A) 3× blank (B) external CBD standard curve from 0-200 uM (C) detection of CBD (m/z 315) in hemp A HA1 extract, (D) HE8 extract (E) HE1 extract, (F) mix of HE8 and HE1 extract, (C1) HA1 extract spiked with CBD-D3 (m/z 318), (D1) HE8 extract spiked with CBD-D3, (E1) HE1 extract spiked with CBD-D3 and (F1) mix of HE8 and HE1 extract spiked with CBD-D3.

(89) FIG. 4 shows the separation and detection of CBD, CBDa, THC and THCa by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1), using a Kinetex™ coreshell resin.

(90) FIG. 4A—CBD alone;

(91) FIG. 4B—THC alone;

(92) FIG. 4C—CBD and THC separation on a 6 cm column;

(93) FIG. 4D, CBD and THC separation on a 15 cm column.

(94) FIGS. 5A and 5B shows the separation and detection of CBD, CBDa, THC and THCa by gradient HPLC and LC-ESI-MS (n=1). FIG. 5A shows the results for Sample 1 spiked with CBD-D3; and FIG. 5B shows the results for Sample 2 spiked with CBD-D3; FIGS. 5C and 5D show CBD and THC reference standards respectively. Gradients—Samples were diluted in B buffer (65% AcN, 5% FA) with gradient 0 min at 70%, 10 min linear gradient to 80%, held for 5 min at 80% and equilibrate at 70% (base peak).

(95) FIG. 6 shows the separation and detection of CBD, CBDa, THC and THCa by isocratic HPLC in 70% AcN 0.1% formic acid and LC-ESI-MS (n=1) on a 15 cm column over Kinetex™ coreshell resin. FIG. 6A shows the CBD and THC reference standard; 6B shows CBD alone; 6C shows THC alone; 6D shows sample A spiked with CBD-D3; 6E shows sample B spiked with THC-D3.

(96) FIG. 7 shows the decarboxylation of CBDa at different temperatures. FIG. 7A, 0.1 g of hemp sample 1 was heated to the appropriate temperature for 1 hour and extracted 3× with 100% Ethanol prior to LC-ESI-MS (n=3); FIG. 7B, 0.1 g of hemp sample 2 was heated to the appropriate temperature for 1 hour and extracted with 100% Ethanol prior to LC-ESI-MS (n=1); FIG. 7C, 0.1 g of hemp sample 2 was heated to the appropriate temperature for 1 hour and extracted with 100% Ethanol prior to LC-ESI-MS (n=3)

(97) FIG. 8 shows a CBD internal vs external standard (ES) curve (n=2) from 50-5000 nM. FIG. 8A shows a CBD external standard curve. FIG. 8B shows an internal versus external CBD curve. FIG. 8C shows an illustration spectra of the detection of CBD (m/z 315) in a hemp sample heated to 120° C. spiked with CBD-D3 (m/z 318) measured by isocratic separation over C18 resin.

(98) FIG. 9 shows an EtOH gradient extraction of CBD. 0.1 g of hemp was heated to 120° C. for 1 hour, extracted in a sequential step gradient of increasing Ethanol and analyzed by LC-ESI-MS (n=3). FIG. 9A shows CBD extracted in ethanol gradient from a hemp sample heated to 120° C. vs no heating control (OC); FIG. 9B shows CBD and CBDa extracted in an ethanol gradient (from 0% to 100% vol in water) from the no heating control sample (OC); FIG. 9C shows CBD and CBDa extracted in an ethanol gradient from a hemp sample heated to 120° C. for 1 hour.

(99) FIG. 10 shows the effect of pH on the extraction of CBD from hemp in 80% Ethanol (n=3). 0.1 g of hemp was heated to 120° C. for 1 hour, washed 3× with H2O, 3× with 40% Ethanol followed by extraction in 80% Ethanol at various pH levels prior to analysis by LC-ESI-MS. Sample 1, 0.1% TFA in 80% EtOH pH>2 (not adjusted); Sample 2, 0.1% FA in 80% EtOH pH2 (not adjusted); Sample 3, 0.1% Acetic acid in 80% EtOH pH3 (not adjusted); Sample 4, 10 mM Citric acid in 80% EtOH pH4; Sample 5, 10 mM Citrate in 80% EtOH pH5; Sample 6, 10 mM Citrate in 80% EtOH pH6; Sample 7, 10 mM Tris in 80% EtOH pH7; Sample 8, 10 mM Tricine in 80% EtOH pH8; Sample 9, 0.1% Ethanolamine in 80% EtOH pH9; Sample 10, 0.1% Ethanolamine in 80% EtOH pH10; Sample 11, 0.1% Ammonia in 80% EtOH pH<10 (not adjusted); Sample 12, 80% EtOH in H2O (pH not adjusted).

(100) The results show that CBD recovery is not significantly affected by the pH of the selective solvent.

(101) FIG. 13 shows optimized binding conditions for CBD using ion exchange chromatography (n=3). 0.1 g of hemp was heated to 120° C. and extracted 3× in 100% ethanol. Extracts of 0.5 g total hemp per replicate were pooled and diluted with H.sub.2O to the appropriate ethanol concentrations. Samples were loaded at 100% ethanol and decreasing to 10% ethanol onto the various resins (DEAE—FIG. 13A, CMS—FIG. 13B, HiQ—FIG. 13C, HiS—FIG. 13D. The Flow Throughs (FT) were collected and analyzed by LC-ESI-MS.

(102) FIG. 14 shows elution curves in Ethanol or Acetonitrile for HiQ columns (n=3). FIG. 14A, ˜7.5 mg CBD was extracted from 0.5 g hemp in 100% Ethanol, diluted to 20% ethanol and loaded onto a ˜100 ul HiQ column. The column was washed with loading solvent prior to elution with increasing amounts of Ethanol (25, 30, 32.5, 35, 37.5, 40, 42.5, 45, 47.5, 50, 55 and 60%). Up to ˜50%, the fractions are observed to be clear. Above 50%, the elutions become green. Fractions were collected and analyzed by LC-MS. FIG. 14B, ˜7.5 mg CBD was extracted from 0.5 g hemp in 100% Acetonitrile, diluted to 20% acetonitrile and loaded onto a ˜100 ul HiQ column. The column was washed with loading solvent prior to elution with increasing amounts of Acetonitrile (25, 30, 32.5, 35, 37.5, 40, 42.5, 45, 47.5, 50, 55 and 60%). Up to ˜35%, the fractions are observed to be clear. Above 35%, the elutions become green (elutions separate in 2 distinct layers, one clear and one green). Fractions were collected and analyzed by LC-MS.

(103) FIG. 15 shows a CBD external standard curve 50-50,000 nM (n=2) measured by LC-ESI-MS/MS using isocratic separation over C18 resin.

(104) FIG. 16 shows the effect of a wash of intermediate resin from cannabis sample A. A 0.1 g aliquot of cannabis sample A was washed in water and heated to 120° C. for 1 hour, extracted in ethanol and dried under vacuum to make an intermediate resin. The water soluble components of the resin were washed in water or water modified with 0.5% acetic acid (v:v), 40% ethanol, salt/ethanol and saturated salt.

(105) The results show that 40% ethanol was a better polar solvent in removing soluble compounds compared to the other solvents from the resin in sample A.

(106) FIG. 17 shows the results of a wash of intermediate resin from cannabis sample B. A 0.1 g aliquot of cannabis sample A was washed in water and heated to 120° C. for 1 hour, extracted in ethanol and dried under vacuum to make an intermediate resin. The water soluble components of the resin were washed in water or water modified with 0.5% acetic acid, 40% ethanol, salt/ethanol and saturated salt. The results show that that 40% ethanol was a better polar solvent in removing soluble compounds compared to the other solvents from the resin in sample B.

(107) FIG. 18 shows the results of a selective extraction of intermediate resin from cannabis sample A. A 0.1 g aliquot of cannabis sample B was washed in water and heated to 120° C. for 1 hour, extracted in ethanol and dried under vacuum to make an intermediate resin. The water soluble components of the resin were washed in water modified with 0.5% acetic acid and extracted with 1 ml of the solvent shown.

(108) FIG. 19 shows the results of extraction of intermediate resin from cannabis sample B. A 0.1 g aliquot of cannabis sample B was washed in water and heated to 120° C. for 1 hour, extracted in ethanol and dried under vacuum to make a intermediate resin. The water soluble components of the resin were washed in water modified with 0.5% acetic acid and extracted with 1 ml of a solvent: acetone, acetonitrile, ether, ethyl acetate, ethanol, hexane, isopropyl alcohol, and methanol.

Definitions and Interpretation

(109) The description of the present invention has been presented for purposes of illustration and description, but it is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. Embodiments were chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. To the extent that the following description is of a specific embodiment or a particular use of the invention, it is intended to be illustrative only, and not limiting of the claimed invention.

(110) References in the specification to “one embodiment”, “an embodiment”, etc., indicate that the embodiment described may include a particular aspect, feature, structure, or characteristic, but not every embodiment necessarily includes that aspect, feature, structure, or characteristic. Moreover, such phrases may, but do not necessarily, refer to the same embodiment referred to in other portions of the specification. Further, when a particular aspect, feature, structure, or characteristic is described in connection with an embodiment, it is within the knowledge of one skilled in the art to combine, affect or connect such aspect, feature, structure, or characteristic with other embodiments, whether or not such connection or combination is explicitly described. In other words, any element or feature may be combined with any other element or feature in different embodiments, unless there is an obvious or inherent incompatibility between the two, or it is specifically excluded.

(111) It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for the use of exclusive terminology, such as “solely,” “only,” and the like, in connection with the recitation of claim elements or use of a “negative” limitation. The terms “preferably,” “preferred,” “prefer,” “optionally,” “may,” and similar terms are used to indicate that an item, condition or step being referred to is an optional (not required) feature of the invention.

(112) The singular forms “a,” “an,” and “the” include the plural reference unless the context clearly dictates otherwise. The term “and/or” means any one of the items, any combination of the items, or all of the items with which this term is associated.

(113) As will be understood by one skilled in the art, for any and all purposes, particularly in terms of providing a written description, all ranges recited herein also encompass any and all possible sub-ranges and combinations of sub-ranges thereof, as well as the individual values making up the range, particularly integer values. A recited range (e.g., weight percents or carbon groups) includes each specific value, integer, decimal, or identity within the range. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, or tenths. As a non-limiting example, each range discussed herein can be readily broken down into a lower third, middle third and upper third, etc.

(114) As will also be understood by one skilled in the art, all language such as “up to”, “at least”, “greater than”, “less than”, “more than”, “or more”, and the like, include the number recited, and such terms refer to ranges that can be subsequently broken down into sub-ranges as discussed above. In the same manner, all ratios recited herein also include all sub-ratios falling within the broader ratio.