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 crosslinked 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. This review analyzes the state of the art of crosslinked ionic polysaccharides as components of delivery systems that 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 (enzymes, illness markers, and so on). Examples of specific applications are provided. The information compiled demonstrates that crosslinked networks of ionic polysaccharides are suitable building blocks for developing advanced externally activated and feed-back modulated drug delivery systems.
Keywords: (dimethylamino)ethyl methacrylate; 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide; 5-ASA; 5-aminosalicylic acid; AAc; Alginate; BSA; CM; CMC; CPG; Carragenan; Chitosan; Chondroitin; Controlled release; DDS; DE; DMA; DS; Dextran; EDC; EGDE; FTIC; IPN; LCST; LDHs; LbL; MMT; PAAm; PBS; PCL; PEI; PEO-PPO-PEO; PNIPAAm; PNaA; PVA; PVP; Pectin; Pyro; SA; SDS; SGF; SIF; SNAP; Scleroglucan; Smart drug delivery systems; TPP; ZPG; bovine serum albumin; calcium pectinate; carboxymethyl; carboxymethyl cellulose; crosslinked alginate particles; degree of esterification; diclofenac sodium; drug delivery system; ethyleneglycol diglycidylether; fluorescein isothiocyanate; interpenetrating network; layer-by-layer; layered double hydroxides; lower critical solubility temperature; montmorillonite; pH-responsiveness; phosphate buffer saline; poli-ε-caprolactone; poly(N-isopropylacrylamide); poly(acrylic acid); poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide); poly(sodium acrylate); poly(vinyl alcohol); polyacrylamide; polyethyleneimine; polyvinylpyrrolidone; pyrophosphate; simulated gastric fluid; simulated intestinal fluid; sodium alginate; sodium dodecyl sulfate; tripolyphosphate; zinc pectinate.
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