Thermal conversion of CBDA and other carboxylic cannabinoids
Inventors
Assignees
Publication Number
US-12071419-B2
Publication Date
2024-08-27
Expiration Date
2042-04-24
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Abstract
This invention is for improving the manufacturing pharmaceutical grade CBD and other cannabinoids following current Good Manufacturing Practices (cGMP) of the US FDA for use in clinical trials for CNS and other indications by the NIH and other researchers. The major cannabinoids in marijuana (Cannabis) and hemp originate from Cannabigerolic Acid (CBGA) present in the biomass of the plant. Plant enzymes that are specific to different strains of biomass converts CBGA to different carboxylic acids of cannabinoids including Cannabidiolic Acid (CBDA) and Δ9-Tetrahydrocannabinolic Acid (Δ9-THCA). These are relatively stable in the growing and fresh-cut plants. These are converted by thermal decarboxylation to Cannabidiol (CBD) and Δ9-Tetrahydrocannabinol (Δ9-THC), carbon dioxide and water. Cannabinoids can be manufactured by first heating the Cannabis biomass to convert carboxylic acids prior to extraction and purification. Alternatively, and preferably because of manufacturing cost and product stability, the carboxylic acids can be first extracted and purified. They can be utilized in the carboxylic acid form or stored in a stable manner until converted to cannabinoids for use in medicine. This invention provides an efficient method for their conversion utilizing a high-pressure reactor under inert conditions.
Core Innovation
The invention provides methods for converting Cannabidiolic Acid (CBDA) to Cannabidiol (CBD), Δ9-Tetrahydrocannabinolic Acid (Δ9-THCA) to Δ9-Tetrahydrocannabinol (Δ9-THC), and other carboxylic cannabinoids to their non-acidic forms using high-pressure thermal conversion systems under controlled temperature and pressure in the presence of inert gases such as carbon dioxide, nitrogen, or argon. These methods can employ solvents such as CO2, alcohols (ethanol or methanol), or mixtures thereof, within a pressurized reaction vessel. The approach enables precise and efficient conversion, offering both batch and continuous flow processing options.
The core problem addressed is the need for reliable, efficient, and scalable manufacturing methods for pharmaceutical-grade cannabinoids that facilitate clinical research and therapeutic use, especially under cGMP guidelines. Traditional preparation methods, such as those relying on smoking or baking, are not conducive to controlled manufacturing or product stability. Furthermore, simply heating extracted plant material often does not yield high purity or stability, limiting the ability to supply cannabinoids at the standards required for medical evaluation and drug development.
This invention enables conversion either before or after extraction and purification, but emphasizes the advantages of isolating stable carboxylic acid forms first, storing them, and subsequently converting them to active cannabinoids as needed under controlled, inert, and pressurized conditions. Experimentation within the patent establishes optimal parameters for temperature, pressure, solvent choice, and residence times for maximal conversion yields with minimal degradation or by-product formation. Supercritical and near-critical fluid technologies, including apparatuses for high-pressure batch or continuous flows, are integral to achieving high conversion efficiency and product quality.
Claims Coverage
The patent contains two independent claims, each introducing a main inventive feature relating to thermal conversion methods and apparatus for cannabinoid carboxylic acids.
Thermal conversion of carboxylic acids of cannabinoids in a pressurized inert atmosphere with specific solvent and pressure conditions
The process involves heating a carboxylic acid of a cannabinoid (including CBDA, Δ9-THCA, and others) in a pressurized reaction vessel under an inert atmosphere. The cannabinoid carboxylic acid is dissolved in a solvent selected from CO2, alcohol (methanol, ethanol), or a mixture of CO2 and an alcohol. The vessel pressure is maintained above the vapor pressure of the solvent at the thermal conversion temperature for a specific duration to achieve conversion to the non-acidic cannabinoid.
Pressurized reaction vessel apparatus for thermal conversion of cannabinoid carboxylic acids under inert atmosphere
The apparatus consists of a pressurized reaction vessel enclosing an inert atmosphere, where the carboxylic acid of a cannabinoid is dissolved in a solvent selected from CO2, alcohol, or a mixture. The system maintains vessel pressure above the solvent's vapor pressure at the conversion temperature for the duration of the process. The apparatus is adaptable to batch or continuous flow operation, and can operate with supercritical, near-critical, critical, or subcritical CO2 (with or without cosolvents such as methanol) at temperature ranges of 25° to 60° C. and pressures of 1,000–5,000 psig.
The inventive features cover a controlled thermal conversion process for cannabinoid carboxylic acids in an inert, pressurized environment utilizing specific solvents and apparatus designed for precision and scalability in pharmaceutical manufacturing.
Stated Advantages
Enables efficient conversion of cannabinoid carboxylic acids to non-acidic cannabinoids with high yield and minimal by-product formation.
Allows for isolation and storage of stable carboxylic acid forms prior to conversion, improving product stability and manufacturing flexibility.
Facilitates pharmaceutical-grade cannabinoid production following cGMP guidelines for clinical evaluation and therapeutic use.
Documented Applications
Manufacturing pharmaceutical-grade CBD, Δ9-THC, and other cannabinoids for clinical evaluation by the NIH and pharmaceutical companies.
Production of standardized Charlotte's Web (CW) product for use by medical marijuana dispensaries for childhood epilepsy.
Manufacture of cannabinoids for therapeutic treatment of pain, opioid addiction, multiple sclerosis, Parkinson's disease, and nausea and emesis.
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