Methods of making cannabinoids

Abstract

The pharmaceutical industry is highly regulated to ensure the safety, efficacy and quality of pharmaceuticals, and drug discoloration is one of the main reasons for drug recalls. It is an object of the present invention to provide an improved process for manufacturing cannabinoids for pharmaceuticals that are both stable and substantially pure. Such use of stable and substantially pure cannabinoids in pharmaceuticals will improve patient compliance with pharmaceuticals. The main steps of the process are decarboxylation, extraction, winterization and crystallization.

Description

Invention Field

[0001] This invention relates to a method for preparing cannabinoids that are both stable and substantially pure. Cannabinoids can be used as active ingredients in pharmaceutical preparations. Background of the Invention

[0003] The pharmaceutical industry is highly regulated to ensure the safety, efficacy, and quality of drugs, as well as the relevance and accuracy of product information. Drug regulatory agencies and manufacturers are paying closer attention to the role of product appearance and physical characteristics in ensuring the safe and appropriate use of drugs. There are concerns that interchangeable drugs with different physical appearances, such as different sizes, colors, and shapes, may lead to medication errors or reduce consumer acceptance of prescribed treatments, undermining patient adherence.

[0004] Discoloration is one of the main reasons for drug recalls (Ahuja S. & Dong M. Elsevier, February 9, 2005, 'Handbook of Pharmaceutical Analysis by HPLC'). Discoloration refers to a change in color from a given appearance of the dosage form. It can occur due to cross-contamination during the manufacturing process or during the transportation, dispensing, and / or storage of the drug product. Because discoloration of drug products can affect their efficacy, degrade products, and impurities, a recall of the drug product is necessary in cases where discoloration has occurred, and the chemical entity causing the discoloration must be identified.

[0005] Cannabinoids have been widely described in the past as medicines used to treat a variety of health conditions. In recent years, cannabinoid-based medicines have become increasingly available to patients in many countries. Currently, there are four commercially available cannabinoid-based medicines. These medicines include: dronabinol. It is a synthetic tetrahydrocannabinol (THC) used to treat anorexia and chemotherapy-induced nausea and vomiting in patients with AIDS; cannabinoids It is a synthetic cannabinoid and THC analogue used to treat chemotherapy-induced nausea and vomiting; nabiximols A complex botanical blend containing THC, CBD, and other plant-derived cannabinoids and non-cannabinoids, approved in Europe as a treatment for symptom improvement in adult patients with moderate to severe spastic states due to multiple sclerosis; and cannabidiol. It contains purified CBD of plant origin, which is approved in the United States for the treatment of seizures associated with Lennox-Gastaut syndrome, Dravet syndrome, or tuberous sclerosis complex in patients aged 1 year or older.

[0006] Epidiolex was developed to provide treatment for seizures associated with Lennox-Gasto syndrome (LGS) and Draway syndrome (DS), characterized by patients with LGS and DS being considered resistant to one or more antiepileptic drugs (AEDs) (see WO 2019 / 97238 and WO 2016 / 203239). Compared to synthetic CBD products that do not contain minor cannabinoid impurities and crude extracts with higher levels of minor cannabinoid impurities, the pharmaceutical product contains plant-derived CBD that has been purified to achieve a specific cannabinoid profile to allow for higher therapeutic potency. This requires careful, controlled preparation and purification methods to meet the specifications of the pharmaceutical product. WO 2019 / 207319 demonstrates the importance of using plant-derived Cannabis and then purifying it, rather than simply using crude extracts.

[0007] Given the contemporary uses of cannabinoids in medicine as outlined above, it has become necessary to find more efficient methods for producing these cannabinoids, especially in stable forms that exhibit a consistent appearance and profile of impurities.

[0008] The standard method for preparing CBD for pharmaceutical use is in Figure 1 The left-hand side is shown. In short, the process involves decarboxylating milled CBD plant raw materials (BRM), followed by extraction with liquid CO2 to produce a crude CBD extract. This crude extract is then winterized to produce a refined extract, which is then crystallized to produce the CBD active pharmaceutical ingredient (API). Therefore, the standard process requires separating two types of CBD extract: a crude extract and a refined extract.

[0009] The process is further detailed in US10583096B2. Dry, milled BRM is decarboxylated by heating in a decarboxylation agitator (DAP) to approximately 150°C to convert naturally occurring cannabidiol (CBDA) in the plant into active CBD. This active CBD then undergoes extraction with liquid CO2 at 60 bar / 10°C to produce an unrefined CBD extract containing approximately 60% w / w to 80% w / w CBD. The remainder of the extract consists of various impurities, including other cannabinoids, long-chain alkanes, terpenes, sterols, and triglycerides. Further methods for the purification and characterization of CBD products are disclosed and described in GB2548873 and GB2574321.

[0010] Winterization involves precipitating long-chain waxy alkane impurities from a 2.0 volume solution of unrefined extract in ethanol. This is achieved by cooling to approximately -20°C over 50 hours in a freezer or to -15°C to -25°C over 4 hours using a temperature control unit. The precipitate is then removed by filtration. Removing the last trace amounts of ethanol from the extract can be difficult and time-consuming. Levels of ethanol greater than 3% w / w in the refined extract can significantly affect crystallization yield. Evaporator capacity and scalability management require splitting extract batches for winterization, creating a bottleneck in the CBD manufacturing process.

[0011] Crystallization was performed from the isolated purified extract. CBD API was crystallized from a purified (hot-filtered) extract solution in 2.0 volumes of n-heptane. The solution was inoculated at 12°C with 0.1% w / w crystalline CBD, allowing seed crystals to begin precipitation (propagation) for 2 hours, after which the suspension was cooled very slowly (over 24 hours) to -18°C to -20°C. The suspension was stirred at -18°C to -20°C for an additional 24 hours to produce a yield prior to filtration. The filtered solids were washed with 4 × 0.25 volumes of brief slurry and displacement washing (at -18°C to -20°C and 10°C), and re-slurryed for 30 minutes in 1.0 volume of solvent at 10°C, for a total of 2.0 volumes of heptane washing solvent. The washed API was dried in a stirred filter dryer at 20°C to 30°C. Therefore, the entire crystallization process is very long, and there is a need for a less complex and more efficient washing process to improve process efficiency and produce high-purity and stable CBD.

[0012] The issue of cannabinoid discoloration has been discussed in many publications.

[0013] US10155176B1 discloses a process for producing cannabinoid products, which optionally also contain a series of terpenes, flavonoids, and other phytoconstituents. It discloses the use of an adsorption and filtration system, particularly without any winterization or crystallization steps. It discusses pretreatment with an adsorbent to remove impurities from a cannabinoid-containing extract feed. One such impurity discussed is chlorophyll, which, when removed from the feed, improves the flavor and produces a lighter-colored final product. The resulting cannabinoid product contains 30%–95% cannabinoids. Stability testing is neither disclosed nor mentioned.

[0014] US10604464B2 discloses a crude cannabinoid extract that is green due to the presence of chlorophyll, and that the chlorophyll is removed using a decolorizing zone, changing the extract's color from green to amber. This would require an additional step in the manufacturing process, reducing process efficiency. The document does not provide any data on the long-term stability of the resulting composition, let alone any short-term stability data.

[0015] Commercially available filter aids exist, such as those sold by the company itself for removing pesticides from cannabis. It provides examples of various pesticides removed from cannabis extracts, such as chlorpyrifos and acetamiprid. Similarly, no data on cannabinoid stability or the purity levels produced by using such filter aids are published.

[0016] Clearly, there is a need for a more efficient and streamlined process for manufacturing cannabinoids for pharmaceutical use that are both stable and substantially pure.

[0017] The object of this invention is to provide an improved method for manufacturing pharmaceutical products containing cannabinoids. Such pharmaceutical products will provide good stability of the cannabinoid active substances, making them feasible for drug development.

[0018] A brief overview of the contents of this disclosure

[0019] According to a first aspect of the invention, a stable, substantially pure cannabinoid is provided, which is obtained by a process comprising:

[0020] a) Decarboxylation step;

[0021] b) Extraction steps to produce a crude extract; and

[0022] c) Combined winterization and crystallization steps, wherein the sub-steps include:

[0023] i) Alkanes are precipitated in a solvent by cooling and removed by filtration;

[0024] ii) Remove the solvent by partial distillation;

[0025] iii) Solvent exchange to heptane;

[0026] iv) Remove the remaining solvent by aqueous phase separation to obtain a heptane solution;

[0027] v) Heat the heptane solution and then filter the heptane solution;

[0028] vi) Cool the solution while stirring at a constant speed;

[0029] vii) The solution is inoculated and seeded to obtain a suspension;

[0030] viii) Cool, stir, filter, and wash the suspension to obtain the product; and

[0031] ix) The product is dehydrated and dried.

[0032] Preferably, the cannabinoids may be selected from the group consisting of: cannabichromene (CBC); cannabichrome acid (CBCV); cannabidiol (CBD); cannabidiol acid (CBDA); cannabidivarin (CBDV); cannabidiol-C1 (CBD-C1), also known as cannabidiorcol; cannabidiol-C4 (CBD-C4), also known as nor-cannabidiol; cannabidiol-C6 (CBD-C6); cannabigerol (CBG); and cannabigerol propyl variant. variant (CBGV); cannabicyclol (CBL); cannabinol (CBN); cannabipropyl variant (CBNV); cannabitriol (CBO); tetrahydrocannabinol (THC); tetrahydrocannabinolic acid (THCA); tetrahydrocannabinol (THCV) and tetrahydrocannabinolic acid (THCVA).

[0033] More preferably, cannabinoids are cannabidiol (CBD).

[0034] In another aspect of the invention, the extraction step is carried out using liquid CO2 at a temperature of 25°C and a pressure of 100 bar.

[0035] Preferably, methanol is used as a solvent in the winterization step.

[0036] Preferably, the winterization step is carried out at a temperature between 0°C and 5°C.

[0037] Preferably, the aqueous phase separation consists of fewer than three aqueous washes.

[0038] In another aspect of the invention, the winterization step uses a vanadium-free filter aid.

[0039] Preferably, the winterization step uses an optional filter aid.

[0040] Alternatively, the winterization step may not use a filter aid.

[0041] In another aspect of the invention, a chelating agent is used in solvent exchange.

[0042] Preferably, the chelating agent is citric acid.

[0043] In another aspect of the invention, one or more antioxidants are added.

[0044] Preferably, one or more antioxidants are citric acid or ascorbyl palmitate.

[0045] In another aspect of the invention, the CBD has a purity of >95% (w / w), preferably greater than 96% (w / w), more preferably 97% (w / w), still more preferably 98% (w / w), and most preferably 99% (w / w) and greater.

[0046] Preferably, THC is present in a concentration of less than 0.15%.

[0047] Preferably, CBDV is present at up to 1%.

[0048] According to a second aspect of the present invention, a process is provided, the process comprising:

[0049] a) The decarboxylation step of cannabidiol (CBD) plant raw materials;

[0050] b) The extraction step of step (a) of the reaction mixture to produce a crude extract; and

[0051] c) The winterization and crystallization steps of the combination of crude extracts from step (b), wherein the sub-steps include:

[0052] i) Precipitate alkanes in the solvent of the crude extract from step (b) by cooling, and remove alkanes by filtration;

[0053] ii) Remove the solvent from the reaction mixture of sub-step (i) by partial distillation;

[0054] iii) The solvent of the reaction mixture from sub-step (ii) is replaced with heptane;

[0055] iv) Remove the remaining solvent from the reaction mixture of sub-step (iii) by aqueous phase separation to obtain a heptane solution;

[0056] v) Heat the heptane solution from sub-step (iv) and filter the heptane solution;

[0057] vi) Cool the reaction mixture from sub-step (v) while stirring at a constant speed;

[0058] vii) The reaction mixture from sub-step (vi) is inoculated and seeded to obtain a suspension;

[0059] viii) Cooling, stirring, filtering, and washing the suspension from sub-step (vii); and

[0060] ix) Dehydrate and dry the reaction material from sub-step (viii) to obtain stable, substantially pure cannabinoids. Brief description of the attached diagram

[0062] The embodiments of the invention are further described below with reference to the accompanying drawings, in which:

[0063] Figure 1 A graphical comparison of non-telescoped and telescoped processes is shown.

[0064] Figure 2 The graph shows the total alkane levels in the winterized extracts after winterization at different temperatures.

[0065] Figure 3 A graph showing the % w / w residual methanol remaining in the heptane solution after continuous water washing is shown.

[0066] Figure 4 The appearance of the pharmaceutical product from Process A relative to the pharmaceutical product from Process B is shown after 2 days and 55 days. The API batches to be formulated into pharmaceutical products are 800346990 and 800347540 to represent Process A (control), and batches are 800342580 and 800340900 to represent Process B.

[0067] Figure 5 A 3D scatter plot of the results is shown to illustrate the color changes of the drug products from Process A and Process B over a 55-day period. Significant differences in the trends were observed between the two different drug products.

[0068] Figure 6Graphical results of elemental analysis for trace metals iron, aluminum, magnesium, and vanadium are shown. Yellow boxes represent the condensation process of API A and API without filter aid, green boxes represent the condensation process API using diatomaceous earth filter aid, and red boxes represent representative condensation process APIs.

[0069] Figure 7 The visual appearance of experiments with higher and lower vanadium doping is shown during the spiking experiment, compared to the positive and negative controls of processes A and B. Over a 14-day period, the lower vanadium doping followed the color change of the process B control.

[0070] Figure 8 Chromatograms are shown to illustrate impurity growth at RRT 0.79 in the low-doped vanadium oxide in the doping experiment and in the process B control. Impurity peaks are outlined with red circles.

[0071] Figure 9 A 3D scatter plot of the colorimetry result of the filter aid-free API is shown compared with the stacked API process and the control process AAPI.

[0072] Figure 10 The pharmaceutical products produced by using optional filter aids at the initial time point (day 0) and the second time point (day 7) are shown.

[0073] Figure 11 The appearance of the batches at the initial time point and at 25°C and 40°C after 7, 14, 21, 28, 56, 84 and 168 days is shown.

[0074] Figure 12 The results of CBD determinations at 25°C and 40°C are shown for all three process B unhelped filter batches from Example 4.

[0075] Figure 13 The results of total degradation products from all three process B unhelped filter batches from Example 4 at 25°C and 40°C are shown.

[0076] Figure 14 The b* values ​​from a colorimetric test at 40°C are shown, comparing the trends of three batches of process B filter aid-free material relative to batch A. The b* values ​​are based on the opposing color theory of blue or yellow.

[0077] Figure 15 The results of total degradation products at 40°C are shown, and the trends of the three process B batches without filter aids relative to process A batches are compared.

[0078] Figure 16A 3D scatter plot shows the colorimetric results of pharmaceutical products produced under different conditions for testing different chelating agents, citric acid, and EDTA.

[0079] Figure 17 It shows that in relation to Figure 16 Overview of impurities and CBD percentage in drug products produced under the same conditions.

[0080] Figure 18 The percentage of degradation products present at three different time points when five different antioxidants were used is shown.

[0081] Figure 19 The images show CBD gels with different antioxidants at the initial time point and on day 27.

[0082] definition

[0083] The definitions of some terms used to describe this invention are detailed below:

[0084] "Substantially pure" cannabinoids are defined as cannabinoids present with a purity greater than 95% (w / w). More preferably greater than 96% (w / w), more preferably 97% (w / w), more preferably 98% (w / w), and most preferably 99% (w / w) and greater.

[0085] "Process A" is used to describe standard, non-overlapping processes.

[0086] "Process B" is used to describe the stacking process claimed in this invention.

[0087] "Optional filter aids" is used to describe the following filter aids: 800 (Fisher) and (Imerys Filtration).

[0088] The cannabinoids described in this application, together with their standard abbreviations, are listed below.

[0089] Table 1: Cannabinoids and their abbreviations

[0090]

[0091]

[0092]

[0093]

[0094] Active pharmaceutical ingredients

[0095] Many cannabinoids exist, and the process according to the invention can be used to produce stable and substantially pure cannabinoids. Such cannabinoids can be selected from the group consisting of: cannabidiol (CBC); cannabidiol acid (CBCV); cannabidiol (CBD); cannabidiol acid (CBDA); cannabidiol (CBDV); cannabidiol-C1 (CBD-C1), also known as cannabidiol; cannabidiol-C4 (CBD-C4), also known as nor-cannabidiol; cannabidiol-C6 (CBD-C6); cannabidiol (CBG); cannabidiol propyl variant (CBGV); cannabicyclool (CBL); cannabinol (CBN); cannabinol propyl variant (CBNV); dihydroxycannabinol (CBO); tetrahydrocannabinol (THC); tetrahydrocannabinolic acid (THCA); tetrahydrocannabinol (THCV) and tetrahydrocannabinolic acid (THCVA). This list is not exhaustive and only details the cannabinoids identified for reference in this application. To date, more than 100 different cannabinoids have been identified, and these cannabinoids can be divided into the following groups: phytocannabinoids; endocannabinoids; and synthetic cannabinoids.

[0096] The process according to the invention can also be used to produce stable and substantially pure cannabinoids, as disclosed in Handbook of Cannabis, Roger Pertwee, Chapter 1, pages 3 to 15.

[0097] Therefore, the process according to the invention can be used to produce all cannabinoids, but CBD is used as an example. Invention Details

[0099] extract

[0100] The extraction efficiency of decarboxylated CBD BRM is improved due to the increased bulk density resulting from granulation and grinding of the material prior to decarboxylation. This increase in bulk density allows for increased loading weight while reducing the total CO2 volume per kg of BRM, and has been shown to yield high yields of CBD extract. In a full-scale batch extraction derived from granular BRM and using BRM decarboxylated at 55 kg CO2 / kg, this yielded good extraction efficiency (~90%) and high product determination (74%). Extraction efficiency was further improved by increasing temperature and pressure (60 bar, 10°C to 100 bar, 25°C).

[0101] Condensation winterization and solvent exchange

[0102] After cooling to 0°C to 5°C (wintering), alkane impurities precipitate from a 2.0 volume solution of the unrefined extract in methanol. Methanol is removed by partial distillation, followed by solvent exchange with n-heptane, and then the remaining methanol is removed by aqueous phase separation (washing). See [link to relevant documentation]. Figure 1 .

[0103] Winterization solvent

[0104] In head-to-head (2.0 volume, 60 min, 20 °C) winterization experiments, methanol winterization was comparable to that from ethanol, with both solvents producing low levels of alkanes (0.03% w / w) in the purified extract (see Table 2). Methanol was readily removed after winterization by distillation and water separation (washing), thus minimizing its impact on crystallization yield.

[0105] The extract (20 g) was tested, and the material was purified at ambient temperature for 1 hour. After filtration, a sample was taken from the filtrate for alkane analysis. The results showed that, in both cases, the alkane levels were very low, even at ambient temperature and with a stirring duration significantly shorter than 1 hour in process A. These solutions were distilled to dryness to separate the purified extract and crystallize. The alkane levels of the separated material were then analyzed. Table 2 shows the alkane content obtained in the batch solution before crystallization and the final product subsequently separated by chromatography.

[0106] Table 2: Comparison of ethanol and methanol used in refining processes (% w / w)

[0107]

[0108] Data indicate that methanol is a more effective solvent for removing alkanes. Although final product analysis showed lower levels of the material separated from ethanol refining, levels from methanol refining were also extremely low, and methanol was chosen as the solvent due to the preference for its cheaper and more readily available bulk supply in plant manufacturing.

[0109] winterization temperature

[0110] A series of winterization experiments were conducted at different temperatures, and the samples were filtered through a liquid bag filtration system at the experimental winterization temperatures. (Bag) filtration. For all the purified extract samples obtained, low levels of alkanes (≤0.25% w / w) were obtained. The lowest alkane levels were obtained from winterization at 0°C to 5°C (see Figure 2 ).

[0111] Alkane filter cake washing

[0112] After filtration of the methanol solution, the alkane filter cake is washed with cold (0°C to 5°C) methanol to remove trace amounts of retained CBD. It has been reported that filtration of the liquid is faster when 2.0 volumes of wash solvent are divided into 0.5 volumes of wash (while a single larger wash is the opposite). Each wash is added to the alkane before the filter cake is dried and cracked.

[0113] Filter aid

[0114] Filter aids are used to help filter alkane because this will significantly reduce filtration time, especially on a larger manufacturing scale.

[0115] Solvent exchange

[0116] Following winterization, methanol was effectively removed by partial distillation and partitioning into the aqueous phase (water washing). After distillation, the methanol solution was solvent-exchanged for n-heptane and vigorously mixed with 2.0 volumes of pure water. The aqueous layer (containing methanol) was separated from the organic phase and removed. This resulted in a generally very low level of methanol in the resulting heptane solution, which was carried over to the crystallization step. Methanol was shown to decrease to <0.5% w / w after the second water wash and to a very low level after the third wash (see [link to crystallization step]). Figure 3 This indicates that three washes will be sufficient.

[0117] Improved crystals

[0118] An improved crystallization process was proposed to enhance process efficiency. The cooling time (from inoculation temperature to separation temperature of -18°C to -20°C) was successfully reduced from 24 hours to 16 hours without adversely affecting particle size. The stirring time from -18°C to -20°C was reduced from 24 hours to 6 hours without affecting yield. The seed propagation time was reduced from 120 minutes to 45 minutes.

[0119] The complexity of the washing process was reduced by eliminating displacement washing. Washing efficiency was further improved by increasing the individual wash volume (to better wet the filter cake). The number of washes was reduced from five to three, while maintaining a total wash volume of 2.0. The improved crystallization process reduced the crystallization time on the equipment by approximately 24 hours.

[0120] Discoloration of pharmaceutical products

[0121] A color difference was observed in CBD drug products using CBD API manufactured via process B (condensation) compared to CBD drug products using CBD API manufactured via process A (non-condensation) route.

[0122] Stability studies were conducted to analyze two drug products from process A and two drug products from process B to assess color differences. Results from process A served as a control when evaluating batches of drug products from process B. Conditions were similar to a "in-use" study, where one amber-colored vial with a screw cap was manufactured for each batch of drug product, stored at ambient temperature (laboratory temperature maintained at 20°C ± 5°C to simulate commercial storage), and opened for sample preparation and testing. The same vial was then reopened at specified time points. Testing was performed over a 55-day period using appearance and colorimetric methods.

[0123] At the initial time point, the solutions from both Process A and Process B were transparent, colorless to yellow. After 2 days, the solution from Process B was significantly more yellow than the solution from Process A, which remained transparent to yellow. (See [reference needed]). Figure 4 Over time, the solution from Process B becomes a deeper yellow, and after 55 days it turns from yellow to light orange. This color change of the solution from Process B over the 55-day period... Figure 5 Records in the middle.

[0124] The stability results of the process A drug product (batch 800347540) shown in Table 3.1 and the process B drug product (batch 800340900) shown in Table 3.2 were recorded over 55 days. The visual appearance of the recorded solutions, as well as the concentrations of degradation products and CBD, were determined using UPLC (ultra-high performance liquid chromatography). The results confirmed the stability of the solutions from... Figure 4 Visual discoveries and from Figure 5 Colorimetric data showed that the process B drug product turned light orange over a 55-day period. As can be seen from Table 3.2, the color change was significant from day 20 for the process B drug product, while the process A drug product remained a clear, colorless to yellow solution (see Table 3.1). Furthermore, it was found that the THC concentration and total degradation product concentration exceeded specification limits from day 30 and day 55, respectively, for the process B drug product (see Table 3.2).

[0125]

[0126]

[0127] Depending on the manufacturer's specifications, filter aids come in various levels of trace elements. Different API samples were submitted for elemental analysis. Figure 6 The data shows a surprisingly high level of vanadium in the cascade process API, compared to the low level present in the process A API.

[0128] Additional screening experiments were conducted using vanadium oxide to assess any potential impact of the element. High-doped (100 mg) and low-doped (2 mg) vanadium oxide were added to 100 mL of ethanol solution containing 10 g of a representative material from Process A. Both the Process A control and the Process B control were run as part of the doping experiment. The results of this screening experiment, namely visual appearance and impurity profile, were... Figure 7 and Figure 8 As shown in the image. Figure 7 The results show that the color change observed in the low-vanadium-doped sample matches that observed in the process B material. Figure 8The chromatograms show that, over the 14-day period, the increase in impurities in the low-doped vanadium oxide matched the increase in impurities from the Process B control. Specifically, the same impurities (circled in red) were recorded for both the low-doped and high-doped vanadium oxide and the Process B control. In the case of higher vanadium doping experiments, this impurity was still present on day 0, indicating accelerated degradation with higher levels of vanadium oxide. The data presented here suggest that vanadium is likely a key contributor to the color changes in this study, particularly at low levels.

[0129] One solution to correct the observed color change is to avoid using any filter aids in the winterization process. In fact, when in Figure 9 When no filter aid is used during the stacking process, color changes are suppressed. However, the removal of the filter aid significantly increases the time required for the filtration process.

[0130] Optionally, different filter aids can be evaluated to assess their impact on the color of the pharmaceutical product. and It is the preferred option among alternative filter aids because the visual appearance of the pharmaceutical product already shows similarity to that of the pharmaceutical product from Process A; see [link to relevant documentation]. Figure 10 and Figure 4 A comparison.

[0131] The following non-limiting embodiments are provided to further illustrate the invention.

[0132] Example 1: Evaluation of APIs with and without filter aids and with optional filter aids

[0133] Analysis of the results without and with optional filter aids ( and The APIs were manufactured under the following conditions and tested for specifications. The appearance, CBD determination, and impurity testing of the API materials were analyzed using liquid chromatography (LC) TM-170, as shown in Table 4. Results for all APIs (4 batches without filter aid and 2 batches with optional filter aid) show compliance with specifications.

[0134] Table 4: Analysis of APIs manufactured without filter aids or with optional filter aids.

[0135]

[0136] Example 2: Pharmaceutical products using APIs manufactured with or without filter aids and with optional filter aids. Assessment

[0137] The pharmaceutical products were formulated using APIs from different manufacturing streams. These streams differed only in the winterization step, and particularly in the filtration step, with or without filter aids. The optional filter aids evaluated were... and Manufacturing and use Three different batches of the filter aid's API, two batches Four batches of the drug product were analyzed without the use of filter aids (see Tables 5.1 and 5.2). A 7-day stability test will indicate whether the drug product performs within specification limits in terms of color and impurity profile. Analysis was also performed on day 35 to observe the stability of the drug product under environmental conditions over a longer period to ensure the stability of the drug product.

[0138]

[0139]

[0140] The results above demonstrate that CBD produced using both the stacking process without filter aids and the stacking process with optional filter aids meets specifications. There is no evidence of any difference in specification test results, and therefore it can be concluded that the changes introduced into the manufacturing process have no negative impact on the quality of the final API. This study indicates that both filter-aid-free and filter-aid-optional pharmaceutical products meet specifications in terms of color, impurity profile, and stability of the pharmaceutical product under environmental conditions over a 35-day period.

[0141] Example 3: Comparability between pharmaceutical products produced by process A and filter aid-free stacking process B

[0142] The purpose of this stability study is to investigate the stability of pharmaceutical products from Process B API produced without a filter aid and to compare them with pharmaceutical products from Process A API. Furthermore, pharmaceutical products from Process B API produced with Clarcel filter aid are used for comparison.

[0143] Bottles were tested under long-term conditions of 25°C / 60% RH and accelerated conditions of 40°C / 75% RH. A summary of the stability tests completed to date is shown in Table 6.

[0144] Table 6: Summary of Stability Tests

[0145]

[0146] The following tests were performed on two batches of process B without filter aid, a control batch of process A, and a batch of process B with Clarcel filter aid. The results are shown in Tables 7.1 and 7.2:

[0147] • Appearance

[0148] • CBD determination by UPLC

[0149] • Degradation products via UPLC

[0150]

[0151]

[0152]

[0153]

[0154] Results from stability studies confirmed the previous findings shown in Table 5, indicating that the pharmaceutical products from Process B API produced without the filter aid were within specification limits. Notably, the Process B pharmaceutical product without the filter aid was comparable to that from Process A API. On the other hand, the pharmaceutical product from Process B API produced with the Clarcel filter aid differed significantly from both Process A and Process B pharmaceutical products without the filter aid in terms of appearance and degradation product levels. Specifically, THC concentrations fell outside specification limits at 25°C for 84 and 112 days (Table 7.1) and from 28 days onwards at 40°C (Table 7.2), while the solution appearance turned dark yellow at the aforementioned time points.

[0155] in conclusion

[0156] Results over 112 days (16 weeks) showed that batches from process B without filter aids were comparable to batches from process A in appearance, CBD, and degradation product concentration at both 25°C and 40°C. Therefore, these results indicate that pharmaceutical products from process B without filter aids maintain the same quality, purity, and stability as pharmaceutical products from process A over extended periods.

[0157] Example 4: Stability of pharmaceutical products produced by filter aid-free stacking process B

[0158] The purpose of this stability study was to investigate the long-term (6 months) stability of pharmaceutical products derived from process B API produced without filter aids. Bottles were tested under long-term conditions of 25°C / 60% RH and accelerated conditions of 40°C / 75% RH.

[0159] A summary of the stability tests completed to date is shown in Table 8.

[0160] Table 8: Summary of Stability Tests

[0161]

[0162] The following tests were performed on three batches of process B without filter aid, and the results are shown in Tables 9.1 and 9.2. Figures 11 to 15 The text shows:

[0163] • Appearance

[0164] Colorimetric method

[0165] • CBD determination by UPLC

[0166] • Degradation via UPLC

[0167]

[0168]

[0169] Under storage conditions of 25°C, all results met the specifications for a transparent, colorless to yellow solution after 168 days (see [reference]). Figure 11 The appearance did not change significantly during the testing period.

[0170] Under accelerated conditions at 40°C, all results met the specification acceptance criteria for a clear, colorless to yellow solution after 24 weeks. No significant changes in appearance were observed during the testing period. At each time point, the batch was slightly darker yellow compared to conditions at 25°C. This is the expected observation and is consistent with what has been observed for pharmaceutical products manufactured using Process A.

[0171] If passed Figure 12 and Figure 13 As can be seen in Tables 9.1 and 9.2, the CBD content and other cannabinoids did not change significantly over the 6-month period. Furthermore, a comparison of the process B batch without filter aid under accelerated conditions at 40°C with the process A batch shows the b* value (see Table 9.1). Figure 14 ) and total degradation products (see Figure 15 There is almost no deviation.

[0172] in conclusion

[0173] After 24 weeks, all results were within their respective specification limits and showed no significant change over the testing period. All results and trends were comparable to the stability results of pharmaceutical products manufactured using Process A.

[0174] Example 5: Addition of chelating agent

[0175] To further optimize the unassisted filtration process B, we investigated whether adding a chelating agent to the washing process could further reduce trace element contamination while maintaining the appearance of the drug product from the unassisted filtration process B.

[0176] Citric acid was compared with EDTA as a candidate chelating agent. Colorimetric data of the API and pharmaceutical products manufactured under the following conditions were recorded over a 14-day period, and the results were... Figure 16 The text shows:

[0177] Citric acid (API filter aid washing)

[0178] Citric acid (API-free filter washing)

[0179] Citric acid (process B filter aid; solvent exchange)

[0180] Citric acid (Process B: no filter aid; solvent exchange)

[0181] EDTA (API-free filter wash)

[0182] Process B Filter Aid

[0183] Process B without filter aid

[0184] Comparison with Process A.

[0185] The concentrations of various impurities and CBD were also measured (excluding the process A control). These results were... Figure 17 As shown in the image.

[0186] Surprisingly, it was found that the addition of citric acid washing during the solvent exchange process in process B (without filter aid) was beneficial in reducing the concentration of degradation products. This was achieved through methods such as... Figure 17 The impurity profile shown in the figure, particularly the profile of RRT 0.76 (purple line), serves as evidence. Colorimetric data also confirm that the addition of citric acid washing will not alter the appearance of the pharmaceutical product, as shown by similar colorimetric profiles for 'Process A Control' and 'Citric Acid (Process B without Filter Aid Solvent Exchange)'.

[0187] in conclusion

[0188] Overall, it is concluded that the addition of citric acid as a chelating agent in solvent exchange can be used to further reduce impurities and degradation products from pharmaceutical products.

[0189] Example 6: Addition of antioxidants

[0190] Further optimization was performed to test whether the addition of antioxidants would reduce degradation products present in the pharmaceutical product. The antioxidants tested are identified in Table 10. Samples were stored at 60°C and evaluated by chromatography.

[0191] In this case, CBD-C4 is used; however, it should be understood that all cannabinoids can be used.

[0192] Table 10: Summary of Antioxidant Tests

[0193] α-Tocopherol 7，27，54 EDTA 7，27，54 BHA 7，27，54 Citric acid 7，27，54 Ascorbyl palmitate 7，27，54 Monothioglycerol 7，27，54

[0194] Results from antioxidant tests Figure 18As shown in the figure, on day 27, the most effective antioxidant was ascorbate palmitate, with degradation products accounting for 0.39% of the active substance, and on day 54, citric acid was the most effective antioxidant, with degradation products accounting for 1.05% of the active substance.

[0195] in conclusion

[0196] Results over up to 54 days indicate that the addition of citric acid and / or ascorbate palmitate as antioxidants may be beneficial in maintaining a low percentage of degradation products in pharmaceutical products.

[0197] Example 7: Further stability studies using antioxidants

[0198] A series of CBD gels were prepared, and their color and degradation were investigated under forced degradation conditions (by HPLC).

[0199] method

[0200] 33% CBD gels were formulated using different antioxidants and placed under forced degradation conditions (60°C). The different antioxidants used were: α-tocopherol, EDTA, sodium metabisulfite, BHA, citric acid, ascorbyl palmitate, and monothioglycerol. The color and analytical characteristics of the gels were observed throughout the forced degradation period to identify any impurities (RRT) corresponding to color changes.

[0201] 10g of 33% CBD gel was prepared using a variety of antioxidants (see Table 11). From the bulk, 0.5g aliquots were placed into 20ml scintillation vials and placed in an oven at 60°C. Samples were removed at multiple time points and subjected to physical and chemical tests. All chemical analyses were performed by HPLC analysis of the CBD gel formulation in hard gelatin capsules.

[0202] Table 11: CBD Gel Components

[0203] Kolliphor P124 3％ Kolliphor P188 38.17％ Triethyl citrate 25％ Antioxidants* 0.5％

[0204] *The antioxidants used are alpha-tocopherol, EDTA, sodium metabisulfite, BHA, citric acid, ascorbyl palmitate, and monothioglycerol.

[0205] result

[0206] Physical analysis

[0207] Figure 19The data presented show the color changes of CBD gels, depending on which antioxidant is present in the formulation. The data shows that gels formulated with the antioxidants alpha-tocopherol, EDTA, sodium metabisulfite, and BHA (batches B1 to B4) turned dark brown / purple. Formulations containing ascorbate palmitate and citric acid (batches B5 and B6) remained yellow after 28 days.

[0208] Chemical Analysis

[0209] The data presented in Table 12 below show that no degradation products were present in the formulation at the initial time point. The only peaks present were CBDV, CBD-C4, and CBD.

[0210] Table 12: Results at Initial Time Points

[0211]

[0212] The data presented in Table 13 show that at day 27, degradation products RRT 0.544, RRT 0.561, RRT 0.599, RRT 0.877, RRT 1.236, and RRT 1.281 were present in formulations containing α-tocopherol, EDTA, sodium metabisulfite, BHA, and monothioglycerol. These degradation products were not found in the citric acid formulation and the ascorbate palmitate formulation. Both formulations (in...) Figure 19 (As shown in the image) It retains its original yellow color and does not degrade into dark brown / purple.

[0213] Table 13: Forced degradation results on day 28

[0214]

[0215]

[0216] in conclusion

[0217] Several antioxidants (as part of a CBD gel formulation) were investigated under accelerated conditions, and visual tests for color and degradation were performed by HPLC. Several antioxidants did not inhibit significant color change, nor did they inhibit the accompanying increase of several impurities.

[0218] Ascorbate palmitate and citric acid showed significant differences, with a markedly minimized color intensity produced in the formulation, and notably, the absence of many key impurities was detectable.

[0219] Overview of the stacking process B (post-extraction step)

[0220] 1. Dissolve the unrefined CBD extract in 2.0 volumes of methanol at 50°C.

[0221] 2. Stir the mixture at 0°C to 5°C for 60 minutes to precipitate waxy impurities.

[0222] 3. The waxy impurities were filtered under vacuum, and the resulting filter cake was washed with 3 × 0.5 volumes of cold methanol to remove trace amounts of retained CBD.

[0223] 4. Distill the methanol solution to a volume of 1.5.

[0224] 5. Add heptane to the concentrated solution according to the required experimental concentration (2.2 volumes) for crystallization.

[0225] 6. Wash the solution with 3 x 2.0 volumes of purified water to separate the aqueous phase containing methanol. IPC confirms that the residual methanol content is within specifications.

[0226] 7. Heat the washed heptane solution to 50°C and hot filter (purify) to remove undissolved particles by washing with 0.3 volumes of heptane (total 2.0 volumes of heptane).

[0227] 8. Cool the solution to 25°C, then slowly cool it to 12°C (over 6 hours).

[0228] 9. Maintain a stirring speed of 115 rpm during crystallization in small equipment (or equivalent if in different containers).

[0229] 10. Inoculate the solution with 1.0% w / w crystallized CBD and allow the seed crystals to grow within 180 minutes (3 hours).

[0230] 11. Cool the suspension to -18°C to -20°C over 960 minutes (16 hours), then stir at -20°C for 360 minutes (6 hours).

[0231] 12. Filter the suspension under vacuum, and then wash it three times with heptane (total volume 3.0).

[0232] • Washing with 2 × 0.75 volume displacement at -18°C and 10°C

[0233] • Re-slurry at 10°C in a 1×1.5 volume for 30 minutes.

[0234] 13. The product is dehydrated and then dried under vacuum at 20°C to 30°C until it meets the specifications for residual heptane.

[0235] The volumes and concentrations mentioned above will be used only as representative values. Different scales will require corresponding adjustments.

[0236] Conclusion

[0237] APIs manufactured in process B, either without or with an optional filter aid, showed compliance with specifications. Drug products manufactured using both the filter-aid-free and optional filter-aid-based processes also met specifications in terms of color, impurity profile, and stability. Notably, this drug product was found to be comparable to that manufactured using control process A over a certain temperature range and over extended periods.

[0238] The addition of chelating agents such as citric acid and antioxidants such as citric acid and ascorbyl palmitate can also improve the impurity profile of pharmaceutical products.

[0239] Therefore, it can be concluded that the process outlined above, which is more efficient and simplified than the previously described method, is capable of producing cannabinoids for pharmaceutical use that are both stable and substantially pure.

Claims

1. A process for forming stable, substantially pure cannabidiol (CBD), the process comprising: a) Decarboxylation step in cannabidiol (CBD) plant raw materials; b) An extraction step of the reaction mixture from step a) to produce a crude extract; as well as c) The winterization and crystallization steps of the crude extract in step b), wherein the sub-steps include: i) The alkanes from the crude extract of step b) are precipitated in methanol by cooling and the alkanes are removed by filtration; ii) Remove methanol from the reaction mixture of sub-step i) by partial distillation; iii) The solvent of the reaction mixture in sub-step ii) is replaced with heptane; iv) Remove the remaining methanol from the reaction mixture of sub-step iii) by aqueous phase separation to obtain a heptane solution; v) Heat the heptane solution from sub-step iv) and filter the heptane solution; vi) Cool the reaction mixture from sub-step v) while stirring at a constant speed; vii) Inoculate and propagate seed crystals in the reaction mixture of sub-step vi) to obtain a suspension; viii) Cooling, stirring, filtering, and washing the suspension from sub-step vii) to obtain the product; and ix) Dehydrate and dry the reaction material from sub-step viii) to obtain stable, substantially pure cannabidiol (CBD).

2. The process according to claim 1, wherein the extraction step is performed using liquid CO2 at a temperature of 25°C and a pressure of 100 bar.

3. The process according to claim 1, wherein the winterization in step c) i) is carried out at a temperature between 0°C and 5°C.

4. The process according to any one of the preceding claims, wherein the aqueous phase separation in step c) iv) consists of two or three water washings.

5. The process according to any one of claims 1-3, wherein the aqueous phase separation in step c) iv) comprises mixing the reaction mixture of sub-step iii) with 2 volumes of purified water.

6. The process according to claim 4, wherein the aqueous phase separation in step c) iv) comprises mixing the reaction mixture of sub-step iii) with 2 volumes of purified water.

7. The process according to any one of claims 1-3 and 6, wherein the aqueous phase separation in step c) iv) reduces methanol to a level of < 0.5% w / w in the heptane solution.

8. The process according to claim 4, wherein the aqueous phase separation in step c) iv) reduces methanol to a level of < 0.5% w / w in the heptane solution.

9. The process according to claim 5, wherein the aqueous phase separation in step c) iv) reduces methanol to a level of < 0.5% w / w in the heptane solution.

10. The process according to claim 1, wherein the winterization in step c) i) uses a vanadium-free filter aid.

11. The process according to claim 1, wherein the winterization in step c) i) does not use a filter aid.

12. The process according to claim 11, wherein a chelating agent is used in the solvent exchange in step c) iii).

13. The process according to claim 12, wherein the chelating agent is citric acid.

14. The process according to claim 1, wherein one or more antioxidants are added.

15. The process according to claim 14, wherein one or more antioxidants are citric acid or ascorbyl palmitate.

16. A stable, substantially pure cannabidiol (CBD) product obtained by a process according to any one of claims 1 to 15, wherein the CBD has a purity of >95% w / w.

17. The cannabidiol (CBD) product according to claim 16, wherein the CBD has a purity greater than 96% w / w.

18. The cannabidiol (CBD) product according to claim 16, wherein the CBD has a purity of 97% w / w.

19. The cannabidiol (CBD) product according to claim 16, wherein the CBD has a purity of 98% w / w.

20. The cannabidiol (CBD) product of claim 16, wherein the CBD has a purity of 99% w / w and greater.

21. The cannabidiol (CBD) product according to any one of claims 16-20, wherein tetrahydrocannabinol (THC) is present in an amount of less than 0.15%.

22. The cannabidiol (CBD) product according to any one of claims 16-20, wherein cannabidiol (CBDV) is present in an amount of up to 1%.

23. The cannabidiol (CBD) product according to claim 21, wherein cannabidiol (CBDV) is present in an amount of up to 1%.

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