Preparation, characterization and preliminary calcium release study of floating sodium alginate/dextran-based hydrogel beads: part I

Ionically crosslinked calcium alginate/dextran-based floating beads were prepared using NaHCO3 as porogen. Various micrometric properties such as tapped density, apparent density, compressibility index, etc., were determined for beads with different compositions. The beads were also evaluated for their mechanical strength. The percent buoyancy of the beads was measured as a function of time in simulated gastric fluid (pH = 1.2 at 37 degrees C). The beads prepared with higher concentrations of NaHCO3 porogen and CaCl2 crosslinker possessed 100% buoyancy and remained buoyant for nearly 20 h, or even more. Finally, the release of calcium from the beads was observed to follow diffusion-controlled Higuchi kinetics. (c) 2007 Society of Chemical Industry.