How to prepare THC-free industrial cannabinoid oil

Abstract

A method for preparing industrial hemp oil is provided. The steps of the method are as follows: industrial hemp is dried at high temperature, extracted with supercritical carbon dioxide to obtain an extract, the extract is winterized to remove winterization, and subjected to molecular distillation to remove impurities, and finally a THC-free industrial hemp extract is obtained by preparative chromatography. When the industrial hemp extract is prepared using the above method, a THC-free industrial hemp extract is obtained without the need for a decolorization step to remove chlorophyll, and the THC-free industrial cannabinoid oil can be further fractionated to obtain CBDV-rich industrial hemp oil and CBD-rich industrial hemp oil, respectively.

Description

[Technical Field]

[0001] The present invention relates to a process for the preparation of industrial hemp extract, and in particular to a method for the preparation of THC-free industrial cannabinoid oil. [Background technology]

[0002] Industrial hemp (Cannabis Sativa) is a dioecious annual herbaceous plant belonging to the Magnoliopsida class, Urticales order, Cannabinaceae family, and genus Cannabis. It is one of the world's oldest annual crops and is cultivated worldwide. It is native to Central and East Asia, and due to its rich content of valuable natural ingredients, it has been used for fiber, seed oil, industrial cannabinoids, and more for 6,000 years. Currently, the whole plant of industrial hemp is widely used in the food, textile, pharmaceutical, cosmetic, and other light chemical industries. Its abundant pharmacological activity is primarily due to the presence of industrial cannabinoids. The therapeutic potential of cannabinoid compounds as antiepileptics, anticonvulsants, antineurodegenerative agents, antiemetics, and analgesics has been extensively studied, and their antibacterial and anti-inflammatory biological properties have also been documented.

[0003] Industrial hemp, a traditional commercial crop, is listed as a narcotic drug under international drug control treaties due to its hallucinogenic and addictive active ingredient, tetrahydrocannabinol (THC). THC is found primarily in the plant's flowers and leaves. The EU assesses industrial hemp based on the percentage of THC content in the dried matter of the plant's flowers and leaves. Currently, more than 500 substances have been reported to have been isolated from industrial hemp plants, including 80 to 100 cannabinol-like compounds. Cannabinol compounds are a type of terpene compound with very similar chemical structures and properties. Tetrahydrocannabinol (THC), a hallucinogenic compound found in industrial hemp plants, has properties most similar to cannabidiol, making separation and purification technology particularly important. The cannabinol compounds in raw plants are complex, with many compounds with similar polarity. Even after extraction and purification using conventional methods, the psychotoxic component tetrahydrocannabinol can still be detected in the final product, making it impossible to guarantee product safety and restricting product distribution, which impacts industrial production and application.

[0004] To improve the yield of industrial hemp extracts, the industry typically uses toxic organic solvents such as petroleum ether, n-hexane, and dichloromethane in process steps such as extraction, extraction purification, and purification. However, the use of such organic solvents not only has a negative impact on the environment, but also makes it impossible to completely remove solvent residues from the final product, affecting product safety. Meanwhile, residual organic solvents in cannabidiol extracts also reduce the quality of the cannabidiol extracts.

[0005] Because the phenolic components of cannabis are complex and contain many compounds with similar polarities, the above-mentioned method, even if produced using the ethanol crystallization process described in CN106831353A, may result in THC and other hallucinogenic or intoxicating components being detected in the product, potentially affecting product safety. Therefore, it is extremely important to develop a method that can completely remove THC and other hallucinogenic or intoxicating components from the product while ensuring product safety, ensuring product yield, and reducing environmental pollution. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a method for preparing a THC-free industrial hemp extract, which comprises drying industrial hemp at high temperature, then extracting with supercritical carbon dioxide to obtain an extract, further winterizing the extract to remove winterization, molecular distilling to remove impurities, and finally preparative chromatography to obtain a THC-free industrial hemp extract. When industrial hemp extract is prepared by the method disclosed in this invention, a THC-free industrial hemp extract is obtained without the need for chlorophyll removal by a decolorization step, and the THC-free industrial cannabinoid oil can be further subjected to secondary fractionation to obtain CBDV (cannabidivarin)-rich industrial hemp oil and CBD-rich industrial hemp oil, respectively. [Means for solving the problem]

[0007] The present invention adopts the following technical solutions:

[0008] 1. A method for preparing a THC-free industrial cannabinoid extract, comprising: (1) Drying: crushing and decarboxylating industrial hemp and drying it until the moisture content is 5% or less; (2) Supercritical extraction: extracting the dried industrial hemp with supercritical carbon dioxide to obtain an extract; (3) Winterization: dissolving the obtained extract in an ethanol solvent, winterizing the solution, filtering and centrifuging the solution after winterization, and concentrating the centrifuged solution under reduced pressure to obtain a winterized extract; (4) Molecular distillation: the dewaxed extract is heated and melted, and then subjected to molecular distillation at a distillation temperature of 170°C to 200°C, and the light fraction obtained by molecular distillation is collected; (5) Preparative chromatography: Separating the light fraction by preparative chromatography using polymeric reversed-phase packing as the packing, which comprises eluting 1 Bed Volume (BV) with 40% to 60% ethanol, discarding the eluate, eluting 8 Bed Volumes with 60% to 70% ethanol, and concentrating the eluate to obtain an industrial cannabinoid extract.

[0009] In some embodiments, in step (1), the moisture content of the industrial hemp after decarboxylation is 4% or less. In step (1), the following method may be used for decarboxylation. First, the raw industrial hemp flowers and leaves are crushed, sieved, and placed in a vacuum microwave dryer while maintaining an appropriate bulk density. The vacuum microwave dryer is then turned on, and the temperature and microwave power of the device are adjusted to carry out the decarboxylation reaction. The decarboxylation temperature of the device is set to 80°C to 100°C, and the reaction time is set to 15 to 25 minutes. Here, the industrial hemp flowers and leaves are crushed and sieved through a 30 to 40 mesh sieve. The output power of the vacuum microwave dryer is 560W to 5000W. The preferred bulk density is 0.2 g / cm. 3 ~0.3g / cm 3 After decarboxylation, the CBDA content drops to less than 0.05%.

[0010] In step (2), the extraction temperature is 40°C to 60°C, and the extraction pressure is 15 to 30 MPa.

[0011] In the step (3), the ethanol solvent is 95% ethanol.

[0012] In some embodiments, the method of the wintering step in step (2) is as follows: the ethanol solution of the extract after decolorization is winterized at −30 to −10°C for a wintering time of 12 hours or more to remove wax components in the industrial hemp extract.

[0013] In some embodiments, the molecular distillation method in step (3) is as follows: turn on the vacuum pump, set the molecular distillation temperature to 170°C to 200°C, and when the distillation temperature reaches 160°C, add the decarboxylated extract to the molecular distillation apparatus and start distillation. When the light phase no longer increases, the molecular distillation is stopped.

[0014] In step (5), the polymer reversed-phase packing comprises one or more of UniPS®, UniPMM®, UniPSN®, UniPSA®, and NM. The preparative chromatography has a chromatography column packing volume of 1300 mL and a column packing height of 26 cm.

[0015] The method disclosed in the present invention further comprises a step of preparing industrial hemp oil enriched with CBDV and industrial hemp oil enriched with CBD, wherein the preparation method further comprises a secondary fractionation step of subjecting the THC-free industrial cannabinoid extract to secondary fractionation using a reversed-phase polymer packed chromatography column, eluting with 8BV of 75% ethanol at an elution rate of 270 L / h, collecting the eluates from 33 to 35 minutes and 56 to 110 minutes, respectively, and then concentrating them to obtain industrial hemp oil enriched with CBDV and industrial hemp oil enriched with CBD, respectively. In CBDV-rich industrial hemp oil, the CBDV mass fraction is 42% or more, and in CBD-enriched industrial hemp oil, the CBD mass fraction is 80% or more. CBDV (cannabidivarin) is a non-psychoactive ingredient that can be used alone or in compositions to treat epilepsy, and in countries and regions where it is legal, it can be used as an active ingredient in pharmaceuticals, health foods, foods, etc. [Effects of the Invention]

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) Conventional techniques often use organic solvents to extract industrial hemp, but these can easily cause environmental pollution and leave organic solvents in the resulting extract. This invention uses supercritical carbon dioxide to extract cannabidiol from industrial hemp. Because carbon dioxide can be recovered and reused through desorption, the working environment is not polluted and no carbon dioxide remains in the resulting cannabidiol product. Extracting cannabidiol from industrial hemp using supercritical carbon dioxide results in high extraction rates of over 90% cannabidiol, eliminating the need for a subsequent decolorization step to remove chlorophyll.

[0018] (2) The THC-free industrial hemp extract obtained by the method disclosed in this invention has a high CBD content of 58% and a CBD yield of up to 89.75%, with no detectable THC content.

[0019] (3) The CBDV-rich industrial hemp oil obtained by secondary fractionation of THC-free industrial hemp extract has a CBDV mass fraction of 42% or more, and the resulting CBD-rich industrial hemp oil has a CBD mass fraction of 85% or more. While producing full-spectrum oil, a higher-quality broad-spectrum oil that does not contain tetrahydrocannabinol can be obtained, expanding the product's application range and significantly increasing economic benefits.

[0020] (4) The present invention employs polymer reversed-phase packing preparative chromatography to prepare industrial hemp extracts, and has the advantages of recyclable packings, a simple preparation process, easy operation, a high degree of industrialization, and low production costs. Compared with conventional separation methods, the production method of the present invention is simple and easy to implement, has stable product quality, is economical and applicable, has low energy consumption, has high yield, and is suitable for large-scale production.

[0021] The present invention uses a step-by-step process of extraction, molecular distillation, and separation and purification by reverse phase preparative chromatography to completely separate tetrahydrocannabinol, ultimately yielding an industrial cannabinoid product free of tetrahydrocannabinol residues, ensuring the safety of the product.

[0022] The following explains the terms used in the present invention.

[0023] In this specification, "industrial hemp" refers to a variety of industrial hemp that has a tetrahydrocannabinol (THC) content of less than 0.3% and has no narcotic value. "Industrial hemp flowers and leaves" refers to the flower and leaf parts of industrial hemp.

[0024] "Wintering" as used herein refers to a process in which wax components contained in industrial hemp extract are precipitated in a crystalline state at low temperatures to obtain an industrial hemp extract that is wax-free or has a low wax content. It is also called the wintering winterization process.

[0025] The "vacuum microwave dryer" in this specification may be a commercially available vacuum microwave dryer, and the drying temperature must be within the range of 80°C to 100°C.

[0026] As used herein, the term "reverse-phase polymer chromatography packing" refers to a reverse-phase chromatography packing that uses a polymer as a matrix. For example, the matrix of the fillers UniPS, UniPSA, and NM disclosed herein is a polystyrene / divinylbenzene (PS / DVB) copolymer, the matrix of UniPMM is a polymethacrylate (PMMA) polymer, and the matrix of UniPSN is a polystyrene / polymethacrylate (PS / PMMA) copolymer (all of the above fillers were purchased from Suzhou Nawei Co., Ltd.). DETAILED DESCRIPTION OF THE INVENTION

[0027] The present invention will be further explained below with reference to examples, but the present invention is not limited thereto.

[0028] Example 1: Preparation method 1 of a THC-free industrial cannabinoid extract The method for preparing a THC-free industrial cannabinoid extract includes the following steps:

[0029] 1) Removal of impurities from raw materials: The industrial hemp raw material was vibrated and sieved to remove impurities, and the industrial hemp stalks and hemp husks were removed from the raw material. The impurity-removed raw material was then crushed into a coarse powder of 30-40 mesh and dried at 120-140°C for 2-4 hours to obtain a crushed raw material with a moisture content of 5% or less, which was then cooled and used.

[0030] 2) Extraction: The cooled raw material was extracted with supercritical carbon dioxide to obtain a supercritical extract. The extraction temperature was 40°C and the extraction pressure was 30 MPa.

[0031] 3) Winterization: 95% ethanol was added to the extract to dissolve it. After complete dissolution, it was winterized at -30 to -10°C for 12 hours. After winterization was completed, it was filtered and centrifuged, and the centrifuged liquid was concentrated under reduced pressure to obtain the winterized extract.

[0032] 4) Molecular distillation: The dewaxed extract was pumped into a molecular distillation tank and subjected to molecular distillation to remove some of the high-boiling impurities (heavy phase) and obtain an oil rich in industrial cannabinoids as a light phase. The distillation temperature was 170°C.

[0033] 5) Preparative chromatography: The light fraction was separated by preparative chromatography using polymeric reversed-phase packing. First, 1 bed volume (BV) was eluted with 40% ethanol. The eluate was discarded, and 8 bed volumes were eluted with 60% ethanol at a rate of 270 L / h. The eluate was concentrated to obtain a THC-free industrial cannabinoid extract. The polymer reversed-phase packing was UniPS, and the chromatography column had a packing volume of 1300 mL and a column height of 26 cm. The resulting THC-free industrial cannabinoid extract was analyzed by HPLC. Its components are listed in Table 1.

[0034] The conditions for HPLC chromatography are as follows: Chromatography column: Waters CORTECS UPLC Shield RP18 1.6 μm 2.1 × 100 mm, Mobile phase: acetonitrile-0.1% formic acid (59:41), Detection wavelength: 228 nm, flow rate: 0.2 ml / min, column temperature: 30°C. Preparation of control products: Control solutions were precisely prepared with concentrations of 20 μg / ml, 1 μg / ml, 10 μg / ml, 0.1 mg / ml, 10 μg / ml, 1 μg / ml, 1 μg / ml, and 1 μg / ml of CBDV, CBDVA, THCV, CBD, CBDA, Δ9-THC, Δ8-THC, and chlorophyll, respectively, using methanol as the solvent. Sample preparation: An appropriate amount of the product of the present invention was taken, weighed accurately, and quantitatively diluted with methanol to prepare a solution containing 0.2 mg of sample per ml. 20 μl of this solution was accurately measured and injected into a liquid chromatograph, and the chromatogram was recorded. The peak areas were compared and calculated to obtain the content of the relevant components in the solution.

[0035] Example 2: Preparation method 2 of a THC-free industrial cannabinoid extract

[0036] 1) Removal of raw material impurities: The industrial hemp raw material is vibrated and sieved to remove impurities, and the industrial hemp stalks and hemp husks are removed from the raw material. The impurity-removed raw material is then crushed into a coarse powder of 30-40 mesh to a bulk density of 0.2 g / cm. 3 ~0.3g / cm 3 The mixture was then placed in a vacuum microwave dryer while maintaining the temperature at 100°C. The vacuum microwave dryer was then turned on and the temperature and microwave power were adjusted to carry out the decarboxylation reaction. The decarboxylation temperature was 80°C to 100°C, and the reaction time was 15 to 25 minutes. The resulting ground material had a moisture content of 5% or less, which was then cooled and used.

[0037] 2) Extraction: The cooled raw material was extracted with supercritical carbon dioxide to obtain a supercritical extract. The extraction temperature was 60°C and the extraction pressure was 15 MPa.

[0038] 3) Winterization: 95% ethanol was added to the extract to dissolve it. After complete dissolution, the extract was winterized at -30 to -10°C for 20 hours. After winterization was completed, the extract was filtered and centrifuged, and the centrifuged liquid was concentrated under reduced pressure to obtain the winterized extract.

[0039] 4) Molecular distillation: The dewaxed extract was pumped into a molecular distillation tank and subjected to molecular distillation to remove some of the high-boiling impurities (heavy phase) and obtain an oil rich in industrial cannabinoids as a light phase. The distillation temperature was 200°C.

[0040] 5) Preparative Chromatography: The light fraction was separated by preparative chromatography using polymeric reversed-phase packing. First, 1 BV was eluted with 60% ethanol, and the eluate was discarded. 8 BV was eluted with 70% ethanol at a rate of 270 L / h. The eluate was concentrated to obtain a THC-free industrial cannabinoid extract. The polymeric reversed-phase packing was UniPSA, and the chromatography column had a packing volume of 1300 mL and a column height of 26 cm. The resulting THC-free industrial cannabinoid extract was analyzed by HPLC. Its components are listed in Table 1.

[0041] [Table 1] Note: " / " means not detected.

[0042] Example 3: Industrial hemp oil 1, rich in various industrial cannabinoids, obtained by secondary fractionation of a THC-free industrial cannabinoid extract

[0043] The THC-free industrial cannabinoid extract obtained in Example 1 was subjected to secondary fractionation using a chromatography column made of polymeric reversed-phase packing UniPS, with a packing volume of 1300 mL, a column height of 26 cm, and elution with 8 BV of 75% ethanol at a rate of 270 L / h. The eluates from 33 to 39 min and 39 to 70 min were collected and concentrated to obtain CBDV-enriched industrial hemp oil and CBD-enriched industrial hemp oil, respectively. The specific components were analyzed by HPLC. Table 2 shows the results.

[0044] The HPLC chromatography conditions for detecting CBDV-rich industrial hemp oil are as follows: Chromatography column: Waters CORTECS UPLC Shield RP18 1.6 μm 2.1 × 100 mm, Mobile phase: acetonitrile-0.1% formic acid (59:41), Detection wavelength: 228 nm, flow rate: 0.2 ml / min, column temperature: 30°C.

[0045] Preparation of control products: Control solutions were precisely prepared with concentrations of CBDV, CBDVA, THCV, CBD, and CBDA of 0.1 mg / ml, 2 μg / ml, 1 μg / ml, 2 μg / ml, and 1 μg / ml, respectively, using methanol as the solvent.

[0046] Sample preparation: An appropriate amount of the product of the present invention was taken, weighed accurately, and quantitatively diluted with methanol to prepare a solution containing 0.2 mg of sample per ml. 20 μl of this solution was accurately measured and injected into a liquid chromatograph, and the chromatogram was recorded. The peak areas were compared and calculated to obtain the content of the relevant components in the solution.

[0047] The HPLC chromatography conditions for detecting CBDV-rich industrial hemp oil are as follows: Chromatography column: Waters CORTECS UPLC Shield RP18 1.6 μm 2.1 × 100 mm, Mobile phase: acetonitrile-0.1% formic acid (59:41), Detection wavelength: 228 nm, flow rate: 0.2 ml / min, column temperature: 30°C. Preparation of control products: Control solutions were prepared with concentrations of CBDV, CBDVA, THCV, CBD, and CBDA of 2 μg / ml, 1 μg / ml, 1 μg / ml, 0.2 mg / ml, and 1 μg / ml, respectively, using methanol as the solvent.

[0048] Sample preparation: An appropriate amount of the product of the present invention was taken, weighed accurately, and quantitatively diluted with methanol to prepare a solution containing 0.2 mg of sample per ml. 20 μl of this solution was accurately measured and injected into a liquid chromatograph, and the chromatogram was recorded. The peak areas were compared and calculated to obtain the content of the relevant components in the solution.

[0049] Example 4: Industrial hemp oil 2, rich in various industrial cannabinoids, obtained by secondary fractionation of a THC-free industrial cannabinoid extract

[0050] The THC-free industrial cannabinoid extract obtained in Example 2 was subjected to secondary fractionation using a chromatography column packed with UniPSA reverse-phase silica gel, with a packing volume of 1300 mL, a column height of 26 cm, and an eluent of 8 BV of 75% ethanol at an elution rate of 270 L / h. The eluates from 33 to 35 min and 56 to 110 min were collected and concentrated to obtain CBDV-enriched industrial hemp oil and CBD-enriched industrial hemp oil, respectively. The specific components were analyzed by HPLC. Table 2 shows the results.

[0051] [Table 2]

Claims

1. 1. A method for preparing an industrial cannabinoid extract, comprising: (1) Drying: crushing and decarboxylating industrial hemp and drying it until the moisture content is 5% or less; (2) Supercritical extraction: extracting the dried industrial hemp with supercritical carbon dioxide to obtain an extract; (3) Winterization: dissolving the obtained extract in an ethanol solvent, wintering after dissolution, filtering and centrifuging after wintering, and concentrating the centrifuged liquid under reduced pressure to obtain a winterized extract; (4) molecular distillation: the dewaxed extract is heated to melt, and then subjected to molecular distillation at a distillation temperature of 170°C to 200°C, and the light fraction obtained by molecular distillation is collected; (5) Preparative chromatography: separating the light fraction by preparative chromatography using polymeric reversed phase packing as the packing, comprising eluting 1 BV (Bed Volume) with 40% to 60% ethanol, discarding the eluate, eluting 8 BV with 60% to 70% ethanol, and concentrating the eluate to obtain the industrial cannabinoid extract.

2. 2. The preparation method according to claim 1, wherein in step (1), the moisture content of the industrial hemp after decarboxylation is 4% or less.

3. The preparation method according to claim 1, characterized in that in step (2), the extraction temperature is 40°C to 60°C and the extraction pressure is 15 to 30 MPa.

4. 2. The method of claim 1, wherein in step (3), the ethanol solvent is 95% ethanol.

5. 2. The method of claim 1, wherein in step (4), the polymeric reversed-phase packing comprises one or more of UniPS, UniPMM, UniPSN, UniPSA, and NM.

6. 2. The method according to claim 1, wherein in step (4), the amount of chromatography column packing is 1300 mL and the column packing height is 26 cm.

7. 2. The method of claim 1, further comprising a secondary fractionation step of subjecting the THC-free industrial cannabinoid extract to secondary fractionation on a reversed-phase polymer packed chromatography column, eluting with 8BV of 75% ethanol at an elution rate of 270 L / h, collecting the eluates between 33 and 35 min and between 56 and 110 min, respectively, and then concentrating them to obtain CBDV-enriched industrial hemp oil and CBD-enriched industrial hemp oil, respectively.

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