FIELD OF THE INVENTION

The invention relates to the field of cannabinoid synthesis, and in particular the chemical processes for making Δ8-tetrahydrocannabinol from cannabidiol extract of industrial hemp having less than 0.3% Δ9-tetrahydrocannabinol using processes that do not permit isomerization of cannabidiol to Δ9-tetrahydrocannabinol to maintain compliance with federal laws throughout processing, and using a differential distillation using vacuum distillation for volatile or low temperature impurities and wipe film distillation to remove high temperature impurities.

BACKGROUND OF THE INVENTION

Cannabinoids are an important class of diverse compounds that connect with brain receptors which are part of the endocannabinoid system. This series of receptors modulates homeostasis throughout the various facets of the human body. The most well-known receptors are the CB1 and CB2 that interact with the central nervous system and immune system respectively. There are over 100 naturally occurring cannabinoids with each affecting the body in specific ways and helping to alleviate a variety of conditions. The cannabinoid discussed in this application, Δ8-tetrahydrocannabinol, has shown great promise in promoting a general state of well-being in the user. According to The National Cancer Institute, Δ8-tetrahydrocannabinol is defined as “an analogue of Δ9-tetrahydrocannabinol with antiemetic, anxiolytic, appetite-stimulating, analgesic and neuroprotective properties.”

Δ8-tetrahydrocannabinol has a lower psychotropic potency than Δ9-tetrahydrocannabinol which may further aid in its acceptance as a medicinal based cannabinoid. Additionally, Δ8-tetrahydrocannabinol binds to both the CB1 and CB2 receptors. CB1 receptors are found in the central nervous system, mainly in the spinal cord and brain. CB2 receptors are found on cells primarily associated with the immune system and are more broadly distributed, therefore influencing most of the body. Since Δ9-tetrahydrocannabinol predominantly interacts with the CB1 receptor, it has a more limited medicinal spectrum than that of Δ8-tetrahydrocannabinol. Lastly, Δ8-tetrahydrocannabinol has shown a reduction of side effects compared to Δ9-tetrahydrocannabinol with patients reporting much less paranoia and lethargy from its use.

Webster, Sarna, and Mechoulam (U.S. Pat. No. 7,399,872) describe a method for producing Δ8-tetrahydrocannabinol where they achieved an 81% yield of 86% Δ8-tetrahydrocannabinol as detected by High Performance Liquid Chromatography (HPLC). This method produces small amounts of Δ9-tetrahydrocannabinol which means that further purification by liquid chromatography is necessary to obtain a purified Δ8-tetrahydrocannabinol product. Our method improves quite significantly on the overall purity and yield of the Δ8-tetrahydrocannabinol in a single step reaction. Mechoulam and Abrahamov (U.S. Pat. No. 5,605,928) also details Δ8-tetrahydrocannabinol's antiemetic effects on children. Eight children were given a dose of Δ8-tetrahydrocannabinol before chemotherapy treatment and it was shown to effectively eliminate all vomiting with little to no side effects. Δ8-tetrahydrocannabinol has been shown to be 200% more effective as an anti-emetic than Δ9-tetrahydrocannabinol and has been especially helpful when used as an anti-emetic in children. (Abrahamov et al, 1995, Life Sciences 56: 2097-2102).

The Farm Bill of 2018 gave farmers in the United States the opportunity to grow industrial hemp on a nationwide basis. Due to many of the cultivars being high in Cannabidiol, there was major interest in cultivation for biopharmaceutical applications. After harvest, industrial hemp is typically processed using solvent such as ethanol, carbon dioxide, or hydrocarbon extraction to create a full spectrum extract. Further purification occurs through distillation and isolation of the Cannabidiol to increase potency and purity of the end product. The Farm Bill of 2018 states that hemp is defined as “the plantCannabis sativaL.” and any part of that plant, including the seeds thereof and all derivatives, extracts, cannabinoids, isomers, acids, salts, and salts of isomers, whether growing or not, with a delta-9 tetrahydrocannabinol concentration of not more than 0.3 percent on a dry weight basis.” Given the large supply of industrial hemp and Cannabidiol in the United States, there exists a need to work towards using this cannabinoid more widely to produce other medicinally beneficial compliant compounds.

SUMMARY OF THE INVENTION

The inventive process starts with an industrial hemp plant that is less than 0.3% Δ9-THC. The cannabidiol (CBD) extract obtained from the compliant (verified less than 0.3% Δ9-THC) hemp is processed to also have less than 0.3% Δ9-THC. The next step of processing with an organic acid, e.g. p-toluenesulfonic acid, in a chemically-related and compatible solvent, e.g. toluene, followed by quenching with a weak base, e.g. sodium bicarbonate, and washing with water, also yields a crude Δ8-THC oil having less than 0.3% Δ9-THC. Thus, the entire Δ8-THC process stays Δ9-THC-compliant at each step. Further performing a short-path vacuum distillation to remove the low temperature impurities ensures that the crude Δ8-THC oil produces a Δ8-THC distillate without allowing cannabidiol to isomerize to the unwanted and non-compliant Δ9-THC. Lastly, performing a wiped film distillation to remove the high temperature impurities also ensures that the Δ8-THC distillate produces a highly pure Δ8-THC oil having >99% Δ8-THC by HPLC without allowing any further isomerization to the unwanted and non-compliant Δ9-THC.

The invention also includes compositions and formulations containing the Δ8-THC oil having >99% Δ8-THC by HPLC.

