Biopolymeric delivery system for controlled release of polyphenolic antioxidants

A chitosan based delivery system has been developed for the controlled release of polyphenolic antioxidants such as catechin. Placebo and catechin entrapped particulate delivery systems were prepared using the sodium tripolyphosphate ionic crosslinking technique. The particles have been characterised by transmission electron microscopy, particle size and charge distribution analysis, Fourier Transform infrared spectroscopy, differential scanning calorimetry and entrapment efficiency studies. These studies gave an understanding of the physico-chemical interactions that influence the biopolymer during particle formation and entrapment of catechin. The in vitro release of catechin was carried out in enzyme-free simulated gastric and intestinal fluids. Although nanoparticles could be formed by the crosslinking technique used, there was aggregation behaviour observed after retrieval and freeze-drying of the particles as shown by transmission electron microscopy. Both the placebo and catechin-loaded particles had mean particle size range of about 4.27–6.29 μm after freeze-drying and were charged. Fourier Transform infrared spectroscopy, differential scanning calorimetry studies indicated minor structural interactions between catechin and chitosan matrix. Entrapment efficiency of the particles ranged between 27% and 40%. In vitro release studies indicated that the release of catechin in simulated gastric and intestinal fluids was between 15% and 40%, depending on the structural interactions between catechin and the chitosan matrix.