Encapsulation complex of chlorine dioxide in α-cyclodextrin: Structure characterization and release property

Abstract

This paper investigated the encapsulation complex (EC) of chlorine dioxide (ClO2) in α-cyclodextrin. The encapsulation process was evaluated with varying molar ratios of ClO2 to α-cyclodextrin; the structure of the EC was characterized using FTIR, XRD, and microscopy imaging; and the release and retention of ClO2 was measured using UV–vis spectrophotometry. Results showed that high ClO2 loading and EC yield were achieved using appropriate ClO2/α-cyclodextrin ratio. Characterization analyses showed that α-cyclodextrin was oxidized by ClO2 and agglomerated into larger particles with modified crystallinity. The retention of ClO2 at −20 °C was stable for at least 3 months. The release of ClO2 followed an anomalous transport process in which diffusion played an important role. The release rate was relatively slow compared to some ClO2 releasing systems reported in the literature, suggesting this EC had potential for applications requiring an extended releasing period.