Co-delivery of zinc and 5-aminosalicylic acid from alginate/N-succinyl-chitosan blend microspheres for synergistic therapy of colitis

The present study developed novel zinc ion cross-linked alginate/N-succinyl-chitosan (NSC) blend microspheres (MS) for co-delivery of zinc and 5-aminosalicylic acid (5-ASA) for synergistic therapy of colitis. Physicochemical characterization of blend MS was assessed using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and energy dispersive X-ray spectrometer (EDS). In vitro release studies demonstrated that blend MS has a pH-dependent release property. Both 5-ASA and zinc have lower release in acid medium and higher release in colonic environment. The therapeutic efficacy of zinc cross-linked blend MS was evaluated using induced-colitis rat models, and showed a superior treatment effect in alleviating inflammation of colitis rats. No systemic toxicity was observed after oral administration of blend MS. Therefore, zinc ion cross-linked alginate/N-succinyl-chitosan blend MS appeared to be a good candidate for co-delivery of zinc and 5-ASA to colon, and had great potential application in inflammatory bowel diseases (IBD) treatment.

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