chondroitin-sulfates and glycidyl-methacrylate

Chondroitin sulfate methacrylate (CS-MA) is a semisynthetic biopolymer increasingly used for the fabrication of chemical hydrogels. In this study, the methacrylation reaction of native CS was carried out with glycidyl methacrylate in dimethyl sulfoxide and optimized to obtain tunable and reproducible methacrylation degrees in a short reaction time. The methacrylation reaction was deeply characterized by mono- and bi-dimensional (1D, 2D) NMR spectroscopy of CS-MA derivatives with different methacrylation degrees. In contrast to what previously reported in the literature, HSQC, HMBC and TOCSY analyses revealed that the methacrylation reaction proceeds via both epoxy ring-opening and transesterification, involving predominantly the primary hydroxyl groups of CS, while preserving sulfate and carboxyl groups of the biopolymer. These findings are of fundamental importance for appropriate and rational design of CS-MA-based biomaterials.

Topics: Chondroitin Sulfates; Epoxy Compounds; Magnetic Resonance Spectroscopy; Methacrylates

The synthesis of nanometer and submicrometer hollow particles could be a motivating way to imprint new therapeutic properties into a chondroitin sulfate-based hydrogel formulation. The use of hollowed polymer structures as a formulation strategy is expected to have an impact in the effective therapy in the treatment of rheumatoid arthritis.. Chemical modification of the chondroitin sulfate with glycidyl methacrylate (GMA) was performed in water under thermal and acid stimuli. The hydrogel spheres were formed upon cross-linking reaction of modified chondroitin sulfate (CSM) in a water-in-benzyl alcohol nano-droplet emulsion.. 1H NMR and 13C NMR spectra showed that the carbon-carbon pi-bonds coming from the GMA were incorporated onto backbones of CS. 13C-CP/MAS NMR spectra revealed that the formation of the CSM hydrogel spheres during the dispersion stage occurred by way of carbon-carbon pi-bonds on the CSM structure. The spherical shapes of the particles with diameters in the range of 20 microm to 500 nm were very clearly verified by SEM images where the dark center and edge of the hollow spheres could be identified easily.. Nanometer- and submicrometer-sized hydrogel spheres with hollow interior were produced from chondroitin sulfate by using a new strategy of hydrogel synthesis.

Topics: Antirheumatic Agents; Benzyl Alcohol; Chemistry, Pharmaceutical; Chondroitin Sulfates; Cross-Linking Reagents; Drug Carriers; Drug Compounding; Emulsions; Epoxy Compounds; Hydrogels; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Methacrylates; Microscopy, Electron, Scanning; Microspheres; Models, Chemical; Nanospheres; Particle Size; Porosity; Surface Properties; Temperature; Water