The regulations in the medicinal Cannabis industry are very strict with respect to controlling the D9-tetrahydrocannabinol (D9-THC) content in final commercial products. Various methods have been developed for the separation of D9-THC from extracts derived from the cannabis plant in order to comply with global regulations. One of these techniques is centrifugal partition chromatography (CPC). CPC is a liquid-liquid chromatography characterized by having a support-free liquid stationary phase. The benefits of having a stationary phase liquid allows: (i) process versatility since either of the immiscible phases can be the stationary or mobile phase; (ii) reduction in loss of sample conventional solid support which can occur in conventional LC; (iii) and increase sample loading capacity. In CPC, compounds are separated according to their respective partition coefficients (K), defined as the ratio of the concentration of a solute in the stationary to that in the mobile phase. The “Arizona system” has been the most widely used in CPC. Given the low polarity of the cannabinoids, a test was carried out a test was carried out with the T, U and V Arizona systems. Best results were obtained using the U system: 4:1:4:1 (heptane/ethyl acetate/methanol/water). This was then altered by using a 4:4:1 (heptane/ethanol/water)system. Using this solvent system, the partition coefficients of cannabidiol (CBD) and D9-THC were found to allow the separation of D9-THC from a CBD-enriched extract. The technique used to calculate K was the well-known shake-flask method. Separation tests were carried out with the CPC and with the analytical results of each fraction a fractogram was building, which showed the separation of THC from CBD in fractions 2 to 8. The cumulative CBD content in this group of fractions was 84.9 % and the THC content, 0.17%. Fractions 10 and waste were enriched in THC (6.58%) and CBC (13.37%). These preliminary results show that it is possible to reduce the D9-THC content and thereby scaling up CPC as a remediation process.

Centrifugal partition chromatography application for delta 9 THC remediation of cannabis extracts

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