Experimental Investigation and Thermodynamic Modelling of Cannabidiol and Curcumin in Different Solvents

Cannabidiol (CBD) and curcumin (CUR) are pharmacologically active substances whose therapeutic effect is limited due to their low water solubility. In this study, we investigated their solubility in different solvents experimentally using the shake flask method and in silico using the COSMO-RS software. We found that CBD is very soluble in DMSO, DMF, acetone, methanol, diethyl ether, isopropanol, ethanol, 1-butanol, PEG 400, triacetin, triethyl citrate, propylene glycol, hexane, isooctane and vegetable oils. CUR is very soluble in DMSO, DMF, acetone and PEG 400 and slightly soluble to insoluble in vegetable oils. The COSMO-RS method shows reasonable relative accuracy (measured as the absolute percentage error) for predicting the solubility of CBD and CUR in solvents in which these compounds are very soluble.