Dextran-based hydrogel microspheres obtained in w/o emulsion: preparation, characterisation and in vivo studies

The cross-linking reaction in w/o emulsions of dextran (DEX) functionalised with methacrylic groups, having or not acid residues in side chain, can be used to easily prepare polysaccharide hydrogel microspheres with properties suitable for drug delivery applications. The formation of a chemical network within the obtained particles was evaluated with FT-IR spectroscopy, whereas morphology and dimensions of the microspheres were investigated with optical and scanning electron microscopy. At the same time, swelling measurements were carried out on freeze-dried particles in different aqueous media simulating biological fluids. Preliminary release experiments performed with ibuprofen, betamethasone and vitamin B12 chosen as model drugs, showed that these microspheres could be suitable as modified drug delivery systems in oral formulations. Finally, in vivo writhing experiments were carried out in mice in order to verify the antinociceptive activity of betamethasone loaded into the new polysaccharide hydrogel microspheres.