Effects of Ethanol on the Supercritical Carbon Dioxide Extraction of Cannabinoids from Near Equimolar (THC and CBD Balanced) Cannabis Flower

In this study, supercritical carbon dioxide (scCO(2)) extractions of cannabinoids were conducted at four different densities (231, 590, 818, and 911 kg/m(3)) using ethanol (5% w/v) as a co-solvent. The chemical profiles of these cannabinoids were analysed via reverse-phase high-performance liquid chromatography (RP-HPLC). It was determined that scCO(2), at low density (231 kg/m(3)), produced an extract yield of 6.1% w/v. At high scCO(2) density (similar to 818 kg/m(3)), the yield was 16.1% w/v. More specifically, the amounts of tetrahydrocannabinol (THC) and cannabidiol (CBD) in the scCO(2) extract at 818 kg/m(3) were 10.8 and 15.6% w/v, respectively. It was also found that the use of 5% w/v ethanol increased scCO(2) extract yields at both low and high densities (7.6% w/v and 18.2% w/v, respectively). Additionally, the use of co-solvent increased this yield further under both low- and high-density conditions, to 13.7 and 19.1% w/v, respectively. Interestingly, higher scCO(2) density (911 kg/m(3)) with and without ethanol did not improve the scCO(2) extract yield or the amount of cannabinoids. Although this study provides new insights into the correlation between scCO(2) density and ethanol co-extraction of CBD and THC, more studies are needed to determine how different scCO(2) densities and co-solvents influence the extraction of cannabinoids.