Controlled drug release from coated floating ion exchange resin beads

Ion exchange resin beads can be loaded with bicarbonate and coated with a semipermeable membrane. These beads exhibit prolonged gastric residence due to release of carbon dioxide which is trapped inside the coating of the beads. In addition to the bicarbonate, a model drug, theophylline, has also been loaded onto the resin. This system gives a controlled release of drug, mediated by the coating, and has potential applications as a controlled release gastric retentive system.