Preparation, characterization and release profile of chitosan alginate freeze dried matrices loaded with mangostins

Freeze drying or lyophilisation method was selected for preparing chitosan-alginate matrices loaded with the extract of mangosteen pericarp for oral administration. The objective of this research was to obtain chitosan-alginate matrices for colon targeted drug delivery system that had a high content of mangostins by using a freeze drying method. Various compositions of matrices consisting of chitosan, alginate and mangostins have been used to study the effect of alginate and mangostin content on the release property of freeze dried matrices. Sharp X-ray diffraction peaks of the crystalline phase in pure chitosan and pure alginate, vanished in the chitosan-alginate matrices. The infrared spectroscopy spectra of matrices showed that mangostins were entrapped in the matrices. Release of mangostin from the chitosan-alginate freeze dried matrices was affected by the proportions of alginate and mangostins in the formulations. The in-vitro release assays in simulated gastrointestinal fluids showed the mangostin was burst released from the chitosan-alginate matrices prepared by freeze drying method. The chitosan extract-alginate matrix with mass ratios of 1:0.1:0.5 showed low release of mangostin in simulated gastric fluid, but high release in simulated intestinal and simulated colonic fluids. The freeze drying method facilitates high bioactive loading, and with a proper proportion of chitosan and alginate, it should be possible to obtain matrices that can be used for colon targeted oral drug delivery.