Micelles/sodium-alginate composite gel beads (micelles/SA beads) were constructed from SA matrix and indomethacin (IND) loaded six-arm block copolymer poly(ε-caprolactone)-block-(dimethylamino)ethyl methacrylate (S(PCL-b-PDMA)6) micelles. The morphology, swelling property and drug loading level of the beads were investigated. The release behaviors of three matrices including micelles, SA beads and micelles/SA beads were evaluated at pH 1.2, 6.8 and 7.4, as well as simulated gastrointestinal (GI) tract, respectively. There was a significant difference between release profiles of each matrix in acidic and near neutral fluid. The results showed that IND was protected by micelles/SA beads from being released in stomach and mainly delivered to the small intestine and colon. The release behavior was also dependent on the initial concentrations of SA and calcium chloride (CaCl2) due to the different crosslinking densities. All results demonstrated that these micelles/SA beads represent a promising oral drug delivery system for poorly water-soluble drugs.
