Ethanol cyclodextrin inclusion complexes with

Reversed-phase liquid chromatography and gas-liquid chromatography have been applied to studies on the complexation of cyclodextrin with isomeric dime-thylnaphthalenes (DMN) 19-22. Both / - and y-CyD have been found to form inclusion complexes with them. With the exception of the complex of 1,8-DMN 22 with yS-CyD, all other complexes under investigation are of weak stability. The stability constant of the former complex is always about 1.5-2.0 orders of magnitude greater than the corresponding value for the other isomers [47]. For example, at 40 °C in 40% of ethanol in water solvent, the stability constants of the complexes of yS-CyD with 1,8-DMN 22 and 1,3-DMN 19 are equal to ca. 500 and ca. 8 respectively. 

Macaudiere et al. first reported the enantiomeric separation of racemic phosphine oxides and amides on native cyclodextrin-based CSPs under subcritical conditions [53]. The separations obtained were indicative of inclusion complexation. When the CO,-methanol eluent used in SFC was replaced with hexane-ethanol in LC, reduced selectivity was observed. The authors proposed that the smaller size of the CO, molecule made it less likely than hexane to compete with the analyte for the cyclodextrin cavity. 

PithaJ and Teruhiko H. Effect of Ethanol on Formation of Inclusion Complexes of Hydroxypropyl Cyclodextrins with Testosterone or with Methyl Orange./rat JPharm 1992 243-251. 

Yoshii H, Kometani T, Furuta T, Watanabe Y, Linko Yu-Y, Linko R 1998. Formation of inclusion complex of cyclodextrin with ethanol under anhydrous condition. Bioscience, Biotechnology and Biochemistry 62 2166-2170. 

P-Cyclodextrins, among other compounds, can be used for the formation of inclusion complexes (cf. 4.3.2). Together with the aroma substances, they are dissolved in a water/ethanol mixture by heating. The complexes precipitate out of the cooled solution and are removed by filtration and dried. Criteria for the evaluation of encapsulated aromas are stability of the aroma, concentration of aroma substance, average diameter of the capsules and, amount of aroma substance adhering to the surface of the capsule. 

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