Flexible heteroionic calcium-magnesium alginate beads for controlled drug release.

In the present work heteroionic calcium-magnesium alginate beads have been prepared by ionotropic gelation using different Ca:Mg ratios. This simple and straightforward approach allowed the obtention of CaMg-alginate beads presenting different mechanical performance depending on the Mg:Ca ratio. The dynamic swelling behavior of the beads was investigated. Increase in the quantity of Mg2+ incorporated in the beads increased the rate of swelling at pH 1.2 and pH 7.2. Finally, the release of ibuprofen was investigated. It was found that increasing the Mg2+ present in the beads raised the drug release rate.