Hemp is increasingly known for its versatile use and is gaining economic importance, including in the pharmaceutical industry. However, since the later demands high quality, it is important to ensure the properness of the chemical profiles of substances intended for use in medicines. As part of our work, we investigated the field of cannabinoid extractions from plant material.
In the first part of the experiments, we tested different methods and extraction conditions. We compared the content of cannabinoids in the sieved and the unsieved fraction of the drug. We found that the CBD and CBDA content is 11.5 % higher in the sieved fraction compared to the unsieved fraction.
We compared the drug that stuck to the metal parts of the grinder during the grinding process and the kind that did not. The content of CBD and CBDA was 58.35 % higher in the extracts from the drug stuck to the grinder compared to the extracts from the drug that was not stuck to the grinder.
We found a simple and convenient extraction procedure for extracting cannabinoids from the drug using plastic syringe. The procedure was carried out by first performing the extraction in a plastic syringe, the extract was then filtered through a tea filter bag, which was placed on the 3D attachment, that allowed filtration in 50 mL centrifuge.
With the help of the “Design of experiments” approach, using the Mixed Full Factorial Design, and the Modde program, we set up an extraction model. We monitored the influence of extraction time and solvent temperature (-78 °C, -24 °C, 0 °C, 24 °C in 50 °C) on the mass fraction and the mass of cannabinoids in the extract.
The highest mass of CBD, CBDA and other substances was extracted in the first minute and a half of extraction at all extraction temperatures tested, and the highest mass fraction of cannabinoids was extracted by the fifth minute.
Purer extracts were obtained at temperatures of -78 °C and -24 °C compared to the ones filtered at room temperature. On the other hand, we found that in addition to waxes and impurities, part of the cannabinoids was also lost.
We concluded that longer time and higher temperature increase the extraction of other substances more than cannabinoids.
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