Sustained Release Properties of Acid Resistant Carboxymethyl Chitosan Gel Microspheres Loaded with Anthocyanins

This study was aimed at broadening the application range of chitosan hydrogels and constructing an edible anthocyanins (ACNs) delivery system. The acid resistant carboxymethyl chitosan (CMCS) gel microspheres (ACNs/CMCS-SA) loaded with ACNs were prepared by inversion-phase emulsion method. During the process, corn oil was used as continuous phase and salicylaldehyde (SA) was used as crosslinking agent. The structure and morphology of ACNs/CMCS-SA were characterized. And the stability, swelling ability and sustained release properties were studied. The results showed that ACNs/CMCS-SA had a micron particle size with smooth and round surface. The gel microspheres showed good acid resistance and pH responsiveness during swelling and sustained release experiments. The sustained release behavior of ACNs conformed to Weibull model. In pH7 and pH9 media, the release process of ACNs was controlled by a combination mechanism of diffusion and skeleton dissolution. In pH3 and 5 media, it was controlled by a combination of Fick diffusion and Case Ⅱ transport (order 0 grade-swelling dependent release). The preparation method of ACNs/CMCS-SA was simple and green, and the sample exhibited good gastric acid protection and intestinal release performance for ACNs. Therefore, this study lays a theoretical and experimental foundation for the development of environmentally friendly drug encapsulation materials and the application of ACNs.