Characterization of calcium alginate and chitosan-treated calcium alginate gel beads entrapping allyl isothiocyanate

摘要

Calcium alginate (CA),chitosan-coated calcium alginate (CCA-I),and chitosan-calcium alginate complex (CCA-II) gel beads,in which an oil-in-water emulsion containing allyl isothiocyanate (AITC) was entrapped,were prepared and characterized for efficient oral delivery of AITC.The AITC entrapment efficiency was 81% for CA gel beads,whereas about 30% lower values were determined for the chitosan-treated gel beads.Swelling studies showed that all the gel beads suddenly shrunk in simulated gastric fluid (pH 1.2).In simulated intestinal fluid (pH 7.4),CA and CCA-I gel beads rapidly disintegrated,whereas CCA-II gel beads highly swelled without degradation probably due to the strong chitosan-alginate complexation.Release studies revealed that most entrapped AITC was released during the shrinkage,degradation,or swelling of the gel beads,and the chitosan treatments,especially the chitosan-alginate complexation,were effective in suppressing the release.CCA-II gel beads showed the highest bead stability and AITC retention under simulated gastrointestinal pH conditions.