Adsorption of Inorganic and Organic Ions to Polycarbophil as a Means of Sustained-Release Dosage Formulation

The adsorption and desorption of drugs and inorganic ions to and from polycarbophil (PC), a polymer, were investigated to determine if PC would be a suitable carrier for sustained-release dosage formulations. Both in vitro and in vivo experiments with a polycarbophil–atropine sulfate complex demonstrated the gradual-release properties of this system. Adsorbed Cr3+ ions, like atropine, are released slowly. In contrast, 51CrO42− ions are predominantly bound in an irreversible manner. A third group of drugs minimally adsorbed to PC under the conditions studied. We conclude that PC under both in vitro and in vivo conditions is able to bind certain ions and drugs and then release them over a period of time in a predictable and repeatable manner.