Summary
Hemp varieties of
Cannabis Sativa
L. contain low levels of Δ
9
-tetrahydrocannabinol (THC) and can be used to produce therapeutic extracts rich in cannabidiol (CBD). In this work, extracts containing up to 449 mg/g CBD were obtained from New Zealand industrial hemp varieties by extraction of flower buds with supercritical CO
2
. The composition of the extracts and the influence of different processing parameters (extraction pressure up to 1300 bar, use of ethanol co-solvent, decarboxylation of feed) were determined. The apparent solubility of the extract in CO
2
at different pressures was measured. Extractions using near-critical propane and dimethyl-ether were also performed. Total extraction yields reached 12.0 wt% with CO
2
and 8.2 wt% with propane, whereas total cannabinoid yield ranged from 51 to 100 % with CO
2
and from 74 to 99 wt% with propane. Addition of 5 % ethanol co-solvent enhances the extraction of cannabinoid acid forms, as does an increase in extraction pressure.
