The goal of the study was to evaluate the influence of the solvent properties on the crystal characteristics of β-cyclodextrin (β-CD) recrystallized from alcohol-water solvent mixtures, with possible applications for the preparation, purifying and complexation of β-CD. For the first time, structure-property relationships (QSPRs) between the hydrophobicity of alcohols or dielectric constant of solvents used for recrystallization of β-CD and its properties (such as crystallinity index, CI) have been obtained. Recrystallized β-CD from water and C1-C4 alcohol-water solutions provide β-CD with higher CI values of 99.4(±5.9)% for ethanol-water (1:4, v/v) as recrystallizing system. This property has a parabolic variation with the logP (octanol/water partition coefficient) of the alcohol (r2 = 0.998). Solvent parameters also influence the β-CD crystal characteristics, as was demonstrated by X-ray diffractometry refinement, infrared spectroscopy and thermal analyses.
Keywords: Fourier-transform infrared spectroscopy; Powder X-ray diffractometry; Principal component analysis; Structure-property relationships; Thermal analysis; β-Cyclodextrin recrystallization.
Copyright © 2021 Elsevier Ltd. All rights reserved.