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Focus on the structure and stimuli-sensitive drug delivery system applications of cross-linked ionic polysaccharides

The review analyses the state of the art of cross-linked ionic polysaccharides as components of drug delivery systems which can regulate drug release as a function of changes in pH, ion nature and concentration, electric and magnetic field intensity, light wavelength, temperature, redox potential, and certain molecules. Polysaccharides are gaining increasing attention as components of stimuli-responsive drug delivery systems particularly since they can be obtained in a well characterized and reproducible way from the natural sources. Ionic polysaccharides can be readily cross-linked to render hydrogel networks sensitive to a variety of internal and external variables, and thus suitable for switching drug release on-off through diverse mechanisms. Hybrids, composites and grafted polymers can reinforce the responsiveness and widen the range of stimuli to which polysaccharide-based systems can respond.