Structure-property relationships on recrystallized ß-cyclodextrin solvates: A focus on X-ray diffractometry, FTIR and thermal analyses.

The goal of the study was to evaluate the influence of the solvent properties on the crystal characteristics of ß-cyclodextrin (ß-CD) recrystallized from alcohol-water solvent mixtures, with possible applications for the preparation, purifying and complexation of ß-CD. For the first time, structure-property relationships (QSPRs) between the hydrophobicity of alcohols or dielectric constant of solvents used for recrystallization of ß-CD and its properties (such as crystallinity index, CI) have been obtained. Recrystallized ß-CD from water and C1-C4 alcohol-water solutions provide ß-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 ß-CD crystal characteristics, as was demonstrated by X-ray diffractometry refinement, infrared spectroscopy and thermal analyses.