Inclusi on complexations of steroid hormones with cyclodextrins in water and in solid phase

Abstract

Inclusion complexation of 18 steroid hormones with 3 cyclodextrins (α, β- and γ-CyDs) in water and in solid phase were studied by the solubility method, spectroscopies (UV, CD, IR and 1H-NMR), X-ray diffractometry and thermal analysis, and their modes of interactions were assessed. A spatial relationship between host and guest molecules was clearly reflected in the magnitude of the stability constant (γ-> β-> α-CyD) and in the stoichiometry of the inclusion complexes. The 1H-NMR studies including spin-lattice relaxation time and chemical shift measurements suggested that the A-ring of the steroid molecule was predominantly included in the cavity of CyDs. The solid complexes of some steroids with β-and γ-CyDs were obtained generally in the molar ratios of 1:2 and 2:3, respectively, and their dissolution behaviors were examined. The results indicated that the CyD complexes may have a great utility as a rapidly dissolving form of steroids in water.