Meta‐analysis and review of cannabinoids extraction and purification techniques

Abstract

Projected revenues of cannabis concentrates and extracts in Canada will reach 5 billion dollars, of which infused products will account for half of the total. The pharmacologically active cannabinoids accumulate in the crop's flowers, accounting for as much as 30% of their dry mass, and are absent from the rest of the plant's body. To achieve a cost effective drug formulation requires optimizing cannabis processing techniques. Here, we review the pre-treatment of Cannabis sativa L., its solvent extraction, and the isolation of its active metabolites. We describe traditional extraction processes such as maceration and percolation with organic solvents, but focus on recent green solvent and methods including supercritical fluid extraction (SCFE) and microwave-and ultrasound-enhanced techniques. Furthermore, we report the decarboxylation kinetics to convert tetrahydrocannabinolic acid and cannabidiolic acid and purification-isolation techniques to satisfy regulatory and consumer requirements. Cannabinoids decarboxylate in 10-60 min at 100-150 C. Ethanol and petroleum ether recover up to 90% of the neutral cannabinoids from plant inflorescences, but the crude extracts require further refining as the purity is less than 50%. Propane and butane compressed gas extraction facilitate solvent removal but introduce safety hazards related to flammability. SCFE is the safest solvent-free extraction method with improved terpenoid recovery and > 80% purity. Academic and commercial interest in the field is expected to accelerate in the next decade due to recent changes in regulatory schemes across North America, which will reduce legal and stigmatic barriers to research.

Development of a solvent screening methodology for cannabinoid recovery from a wax by-product via recrystallization

“…RP is a measure of the degree of interaction of the solvent with various polar test solutes and is an experimentally determined value based on a solvent's solvation ability, relative to that of pure water. Subsequent parameters used as screening tools in order of evaluation were boiling point temperature (T b ), safety of use, and Kamlet-Taft parameters for acidity, basicity, and polarity (α, β, and π*) [4,5,7,9,10].…”

“…1, from where the recovered cannabinoids are set to be reintroduced to the overhead stream before the primary distillation stage. Primary extraction generally implements the use of ethanol as the working solvent, and after winterization and solvent evaporation, the resulting concentrate can have a cannabinoid content of up to 70% (w/w) [4]. The fractionation of plant waxes is often achieved through the use of a solvent, typically liquid substances in which other substances (solutes) can dissolve and be recovered unchanged through the removal of the solvent [4,5].…”

“…Primary extraction generally implements the use of ethanol as the working solvent, and after winterization and solvent evaporation, the resulting concentrate can have a cannabinoid content of up to 70% (w/w) [4]. The fractionation of plant waxes is often achieved through the use of a solvent, typically liquid substances in which other substances (solutes) can dissolve and be recovered unchanged through the removal of the solvent [4,5]. Selective dissolution of solutes in the solvent results in the separation of compounds based on solubility [6].…”

Optimization of Supercritical Carbon Dioxide Fluid Extraction of Medicinal Cannabis from Quebec

“…The cannabis plant was originally used in central Asia during the Neolithic period. Western medicine adopted medicinal cannabis in the 1800s, when the Irish physician William O'Shaughnessy and French psychiatrist Jacques-Joseph Moreau attempted to treat tetanus, rabies, and mental disorders with it [1]. For example, dronabinol, a synthetic tetrahydro-cannabinoid (∆ 9-THC), is effective for anorexia, nausea, and vomiting, and was initially approved by the FDA on 31 May 1985 [2].…”

Preface to the special issue section: 74th Indian Chemical Engineering Congress (CHEMCON‐2021)

“…Soni et al [ 5 ] describe the development of a code for non‐linear data reconciliation to reduce measurement errors in the data acquired from chemical plants. Song et al [ 6 ] present a review of the pre‐treatment, processing, extraction, and purification techniques for obtaining cannabis concentrates and extracts. Yahyazadeh et al [ 7 ] evaluate the CO activation mechanism and consumption rate during the Fischer–Tropsch reaction through detailed experimentation with KMo bimetallic‐promoted Fe catalyst supported on carbon nanotubes.…”