Dissolution of calcium ions from alginate matrix / Nur Hazirah Kamarudin

The profiles of calcium ion leaching from alginate beads in relation to the property of dissolution medium modified by microwave were investigated. The beads were prepared by extrusion method with sulphanilamide, sulphathiazole and sulphamerazine as model drugs. The dissolution medium was subjected to microwave treatment at 80 W and 300 W. The profile of calcium release was determined by dissolution testing and atomic absorption spectrophotometry techniques. Untreated water possessed more dissolved carbon dioxide and thus led to the formation of carbonic acid. The protons from acid replaced calcium ions and increased the percentage of calcium release when relatively alginate sulphanilamide beads were concerned. The water treated by microwave at 300 W had sufficient kinetic energy to penetrate into the alginate beads. The kinetic energy of water enabled the polymer to loosen their matrix crosslinkages through dissociation of calcium ions from alginates beads. A more hydrophobic alginate-sulphathiazole bead required such water to induce calcium leaching. Lastly, in the case of alginate­ sulphamerazine beads there was no apparent effect of dissolution medium treated by microwave on their calcium leaching profile.