Amoxycillin release from a floating dosage form based on alginates

Floating alginate beads have been prepared from alginate solutions containing either dissolved or suspended amoxycillin. The beads were produced by the dropwise addition of the alginate into calcium chloride solution, followed by removal of the gel beads and freeze drying. Drug release studies showed that beads prepared with the drug in solution provided some sustained release characteristics and that these could be improved by the addition of amylose. In all cases, the drug release was consistent with release of a dissolved solute from a granular or porous matrix. The beads retained their buoyancy when amylose and amoxycillin were incorporated, exhibiting resultant weight values greater than zero after 20 h. Preparation of the beads from alginate solutions containing the drug in suspension allowed higher drug loadings, at the expense of faster release and lower buoyancy.