Chitosan hybrid microgels for oral drug delivery

In the present work, hybrid microgels based on chitosan and SiO2 nanoparticles (NPs) were synthesized. Both chitosan and the SiO2 NPs were submitted to chemical modification reactions to having vinyl groups incorporated into their structures. The microgels were synthesized by emulsion polymerization. SEM analysis indicated a high dispersity of diameter for the microgels, ranging between (18.7 +/- 12.3) mu m for the samples without SiO2-VTS and (11.3 +/- 8.07) mu m for the microgels with SiO2-VTS. The material showed pH-responsiveness, especially in acidic pHs. The longest release lasted 45 min and large amounts of drugs were released as soon as the material was added to the release medium. It is interesting for oral drug delivery systems, especially for gastric wound treatment. The fast release of high amounts of drugs promotes an immediate relief of the pain and the following controlled release allows the gradual recovery of the damaged area.