Complexation with Cyclodextrin Improves Solubility of Cannabidiol (Chemistry)

Recently, a research group from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences prepared the inclusion complexes (ICs) with cyclodextrin for improving the solubility of cannabidiol (CBD), which in turn can enhance the bioavailability of CBD.

The study was published in Journal of Molecular Liquids on April 8. 

CBD has a wide variety of biological activities, and it is one of the phytocannabinoids from Cannabis sativa L (Hemp). However, due to the poor aqueous solubility, its applications in food, cosmetic, and pharmaceutical fields are limited. 

Cyclodextrins (CDs) are useful materials to improve the solubility of poorly water-soluble molecules. Therefore, the researchers used β-cyclodextrin (β-CD) and 2, 6-di-O-methyl-β-cyclodextrin (DM-β-CD) to prepare CBD/β-CD IC and CBD/DM-β-CD IC by freeze-drying method to improve the water solubility and dissolution rate of CBD. 

Moreover, the results of molecular docking further showed that CBD was encapsulated successfully. 

Job’s plot and phase solubility study revealed that CBD formed ICs with β-CD and DM-β-CD at a stoichiometric ratio of 1:1. The thermodynamics analysis demonstrated that the inclusion process was spontaneous and endothermic. The loading efficiency (LE) of CBD/β-CD IC and CBD/DM-β-CD IC was 20.4% and 17.7%, respectively, while the complexation efficiency (CE) was 92.4% and 90.8% respectively. 

Moreover, the water solubility of CBD in CBD/β-CD IC and CBD/DM-β-CD IC was significantly increased to 0.395 and 14.118 μg/mL, which was enhanced by 17-fold and 614-fold respectively at such a high LE, and the in vitro dissolution rate of CBD was also promoted. 

The antioxidant activity of CBD was improved after encapsulation. Significantly, the ABTS free radical scavenging ability of the ICs was better than that of Vitamin C. 

A peer reviewer fromJournal of Molecular Liquids said the study was “well organized and described the concept of complexation very well”.  

The researchers hoped that this work could provide theoretical and experimental support for expanding the application of cannabidiol.

Reference: Hang Li, Sen-Lin Chang, Tan-Ran Chang, Ying You, Xiao-Dong Wang, Li-Wei Wang, Xiao-Fan Yuan, Ming-Hui Tan, Pei-Dong Wang, Peng-Wei Xu, Wei-Bo Gao, Qing-Sheng Zhao, Bing Zhao, Inclusion complexes of cannabidiol with β-cyclodextrin and its derivative: Physicochemical properties, water solubility, and antioxidant activity, Journal of Molecular Liquids, 2021, 116070, ISSN 0167-7322, (

Provided by Chinese Academy of Sciences

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