Cannabis is a genus of flowering plants whose species are distinguished by plant phenotypes and secondary metabolite profiles. At least three species are recognized, Cannabis sativa, C. indica, and C. ruderalis. Cannabis plants have been cultivated for a variety of uses including making fibers (hemp), medicinal use and recreational drug use. Cannabis is also commonly known as marijuana.
Cannabis has now been generally acknowledged as having substantial benefits for various medical uses. For example, cannabis is regularly used by a wide cross-section of society to treat a variety of maladies, ailments and symptoms including, but not limited to, nausea, pain relief (such as chronic pain, cancer related pain, or neuropathic pain), glaucoma, lack of appetite, mucous membrane inflammation, inflammatory diseases (such as Crohn's disease), neurodegenerative disease, epilepsy (that affects children and adults), seizures, diabetes, leprosy, fever, obesity, asthma, urinary tract infections, coughing, anorexia associated with weight loss in AIDS patients, graft-versus-host disease, glioma, perinatal asphyxia and post-traumatic stress disorder (PTSD) and autoimmune disease (such as multiple sclerosis).
One of the most common ways that cannabis is used for medicinal use in many countries is through smoking. Smoking medical cannabis, although proven to be beneficial in certain indications, has disadvantages. For example, the amounts of active ingredients may differ depending on the differences present in plant varietals as well as changing growing conditions which result in intravarietal variations. As a result, it can be difficult to maintain control over the proper dosing of medicinal cannabis due to active ingredients fluctuations. Another disadvantage of smoking medical cannabis is the negative impact of some of the constituents of cannabis smoke. The smoke from the plant matter comprise carcinogens in addition to the desired cannabinoids. In addition, heavy cannabis use through smoking has been associated with accelerated pulmonary decline.
Cannabinoids are compounds active on cannabinoid receptors in humans and are responsible for eliciting many of the pharmacological effects of cannabis. Cannabinoids of plant origin, also known as phytocannabinoids, are abundant in Cannabis. Two known cannabinoids which are present in relatively high concentrations in Cannabis sativa L. are tetrahydracannabinolacid (THCA) or its decarboxylated product tetrahydracannabinol (THC) and cannabidiolic acid (CBDA) or its decarboxylated product cannabidiol (CBD). THC elicits psychoactive (calming) effects, analgesic effects, antioxidant effects and to increase appetite. However, THC is also associated with many negative or undesirable side effects including, but are not limited to, decreased short-term memory, dry mouth, impaired visual perception and motor skills, erectile dysfunction, lower fertility, red (i.e., blood shot) eyes, increased anxiety, occasional infarction, stroke, paranoia, acute psychosis, lowered mental aptitude, hallucinations, bizarre behavior, irrational panic attacks, irrational thoughts and various other cognitive and social problems. On the other hand, CBD is increasingly becoming a popular cannabinoid for medicinal purposes because unlike THC, CBD is non-psychoactive at typical doses. In addition, CBD was found to have neuroprotective effects and to have ameliorative effects in patients with schizophrenia and Parkinson's disease. Accordingly, patients and healthcare providers are exhibiting a preference for CBD because patients need to work, drive and function with clarity while undergoing treatment.
Efforts have been made to reduce the amount THC in cannabis and cannabinoid products without significantly reducing the therapeutic effects of other non-psychoactive cannabinoids. One way is to selectively breed cannabis varietals having an increased CBD:THC ratio. However, such cannabis varietals would still need to be administered by smoking, exposing the patient to its associated disadvantages and detrimental health effects. Another way to selectively manage or eliminate THC using a series of fractionating columns. Diverse chromatographic techniques have been used purify cannabinoid compounds from the plant Cannabis sativa. For example, Flash chromatography on silica gel, C8 or C18; preparative HPLC on silica gel columns, C8 or C18; and supercritical CO2 chromatography on silica gel. However, these chromatographic processes are tedious and expensive.
Thus, what is needed is a simple and less expensive process that selectively purifies and concentrates medically beneficial cannabinoids from THC, thereby lowering THC content as a percentage of the cannabinoid mix. In addition, it is also desirous to develop medicinal formulations comprising higher levels of beneficial cannabinoids while at the same time having a lowered THC content. However, THC and THCA can also be purified by this method from THC-THCA rich or THC-THCA low Cannabis extracts.
Centrifugation partitioning chromatography (CPC) and counter current chromatography (CCC) can be used, e.g., in the extraction and enrichment of compounds from plant extracts in analytical, semi-preparative and preparative scale. CPC and CCC are a liquid-liquid chromatography methods using a mostly two-phase solvent. It enables an almost loss-free separation of complex mixtures of substances from crude extracts. CPC and CCC as compared to liquid chromatography (HPLC) is easier and also cheaper, because matrix effects and irreversible adsorption on solid phases do not occur. Cannabinoids have been purified using CPC, but not using the solvent systems described in this patent application (see, e.g., Hazekamp, et al., “Preparative Isolation of Cannabinoids from Cannabis sativa by Centrifugal Partition Chromatography”, Journal of Liquid Chromatography & Related Technologies, vol. 27, no. 15, 11 Jan. 2004 (2004-01-11), pages 2421-2439, XP055202081, ISSN: 1082-6076, DOI: 10.1081/JLC-200028170; see also WO2016/135346). These systems have long run times, less sample load and only moderate yields.
The present disclosure solves these and other problems by providing a method for isolating and purifying cannabinoid compounds using a solvent system and centrifugation partition chromatography (CPC) or counter current chromatography (CCC). In the case of CPC, there is significantly less time on the centrifuge and a large sample load, using the Quantum CPC rotor (ARMEN) or the CPC 1000 PRO (GILSON). By means of this procedure it is possible to obtain high yields of cannabinoid compounds having a purity of 95% or more.
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