Water-soluble polyelectrolytes for oral controlled drug delivery systems.

摘要

Pharmaceutical dosage forms based on commercially available ion exchange resins have been reviewed. Previous investigations on the sustained release properties of drug resin complexes showed promise, however being cross-linked gel systems they were prone to certain limitations. Drug resin complexes prepared from them showed Fickian release profiles with a long tailing and incomplete release. Based on these advantages and limitations, improved systems have been proposed, designed and developed for the controlled release of ionic drugs using water-soluble polyionic carriers. Their synthesis, characterization and complexation with drugs are described. Several anionic and cationic water-soluble polymers were complexed with oppositely charged drugs and formulated into tablets. In vitro release studies under various conditions were performed to determine the drug release mechanism as well as the factors affecting drug release rate from these polymers. Zero-order drug release and. a dissociation-erosion mechanism of drug release were observed. The linearity of the release profiles and the dissociation/erosion rate constants were mathematically determined. The effects of particle size, compression force, hydrodynamic conditions, buffer composition, nature of drug, polymer composition and tablet dimensions on drug release rates are discussed and the merits of these systems are evaluated in light of previously used materials.