Preparation, quantitive analysis and bacteriostasis of solid state iodine inclusion complex with β-cyclodextrin

Abstract

A solid state iodine/β-cyclodextrin inclusion complex (iodine/β-CD) was prepared by the saturated water solution method. The iodine/β-CD binding constant was 1,286 M−1 and the stoichiometric ratio was 1:1(I2: β-CD). In order to determine the iodine content in the complex powder, a novel iodimetry method was investigated, and its accuracy and expeditiousness were verified by high performance liquid chromatography (HPLC). Release behaviors of iodine/β-CD powder were investigated by iodimetry and thermogravimetric (TG) analyzer respectively. The loss percentage of iodine was 5.8wt% for 7 days exposing under room temperature, and a time versus release curve was established. The TG diagram not only proved the stability of I2 in the iodine/β-CD complex, but also clarified the thermal decomposition behavior of the iodine/β-CD. For verifying the germicidal activity of iodine encapsulated by β-CD, the Aspergillus niger, a kind of common fungus in the food, was taken as an evaluation media. The results indicate that by the method of disc diffusion, the discs with 1.5wt% iodine showed an obvious bacteriostasis effect for Aspergillus niger.