N-Succinyl-chitosan systems for 5-aminosalicylic acid colon delivery: in vivo study with TNBS-induced colitis model in rats.

5-Aminosalicylic acid (5-ASA) loaded N-Succinyl-chitosan (SucCH) microparticle and freeze-dried system were prepared as potential delivery systems to the colon. Physicochemical characterization and in vitro release and swelling studies were previously assessed and showed that the two formulations appeared to be good candidates to deliver the drug to the colon. In this work the effectiveness of these two systems in the treatment of inflammatory bowel disease was evaluated. In vitro mucoadhesive studies showed excellent mucoadhesive properties of both the systems to the inflamed colonic mucosa. Experimental colitis was induced by rectal instillation of 2,4,6-trinitrobenzene sulfonic acid (TNBS) into male Wistar rats. Colon/body weight ratio, clinical activity score system, myeloperoxidase activity and histological evaluation were determined as inflammatory indices. The two formulations were compared with drug suspension and SucCH suspension. The results showed that the loading of 5-ASA into SucCH polymer markedly improved efficacy in the healing of induced colitis in rats.