Enhancing effect of choline chloride-based deep eutectic solvents with polyols on the aqueous solubility of curcumin–insight from experiment and theoretical calculation

• Published in: Chinese journal of chemical engineering Vol. 59; no. 7; pp. 160 - 168
• Main Authors: Yu, Wen, Bo, Yiyang, Luo, Yiling, Huang, Xiyan, Zhang, Rixiang, Zhang, Jiaheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-07-2023; Research Centre of Printed Flexible Electronics,School of Materials Science and Engineering,Harbin Institute of Technology,Shenzhen 518055,China
• Subjects: Aqueous solubility; Choline chloride-polyol; Curcumin; Deep eutectic solvents; Theoretical calculation; Curcumin; Theoretical calculation; Deep eutectic solvents; Aqueous solubility; Choline chloride-polyol
• ISSN: 1004-9541; 2210-321X
• DOI: 10.1016/j.cjche.2023.01.005

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•ChCl/polyol DESs were effective co-solvents for enhancing CUR aqueous solubility.•ChCl/1,2-PDO (1:4) was a promising green alternative to organic co-solvents.•Modified Apelblat equation was more accurate than λh equation and Yalkowsky model.•Hydrogen bonds and van der Waals interaction retained the DESs structure stability.•The predominant interactions between DESs and CUR were van der Waals attractions.
The development of green solvents for enhancing aqueous solubility of drug curcumin remains a challenge. This study explores the enhancing effect of deep eutectic solvents (DESs) on the aqueous solubility of curcumin (CUR) via experiment and theoretical calculation. Choline chloride-based DESs with polyols 1,2-propanediol (1,2-PDO), 1,3-propanediol, ethylene glycol, and glycerol as hydrogen bond donors were prepared and used as co-solvents. The CUR aqueous solubility increased with increasing the DESs content at temperature of 303.15–318.15 K, especially in aqueous ChCl/1,2-PDO (mole ratio 1:4) solutions. The positive apparent molar volume values and reduced density gradient analysis confirmed the existence of strong interactions between CUR and solvent. The van der Waals interactions and hydrogen bonding coexisted in DESs monomer retained the stability of DESs structure after introducing CUR. Moreover, the lower interaction energy of DESs⋅⋅⋅CUR system than that of the counterpart DESs further proved the strong interaction between CUR and DESs. The lowest interaction energy of ChCl/1,2-PDO⋅⋅⋅CUR system indicated that this system was the most stable and ChCl/1,2-PDO was promising for CUR dissolution. This work provides efficient solvents for utilizing curcumin, contributing to a deep insight into the interactions between DES and CUR at the molecular level, and the role of DESs on enhancing drugs solubility.