Colon-specific delivery of budesonide from microencapsulated cellulosic cores: evaluation of the efficacy against colonic inflammation in rats

Budesonide (BIDS) is a potent corticosteroid that has important implication s in the pharmacotherapy of inflammatory bowel disease, especially in the t reatment of ulcerative colitis and Crohn's disease. BDS is available on the market in the form of enteric-coated preparations. However these products, similar to other available site-specific dosage forms, are not sufficientl y selective to treat colonic inflammatory bowel disease. The objective of t his study was to evaluate the efficacy of a new microparticulate system con taining BIDS, to treat experimentally induced colitis in rats. This micro p articulate system consisted of BDS-containing hydrophobic cores, microencap sulated within an enteric polymer, which solubilizes at above pH 7, thus co mbining pH-sensitive and control led-release properties. Colonic injury and inflammation were assessed by measuring colon/bodyweight ratio, myeloperox idase (MPO) activity, and by scoring macroscopic and histological damage in colitic rats. Rats were treated orally with BIDS, included in the develope d system, once a day for 4 days after the induction of inflammation. A BDS suspension and BDS-containing enteric microparticles were included as contr ol formulations in the experimental design. The administration of the new B IDS delivery system significantly reduced the colon/bodyweight ratio compar ed with the administration of control formulations. Similarly, MPO activity and macroscopic and histological damage of the inflamed colonic segments d ecreased significantly when the BIDS formulation was administered, compared with the results obtained after oral administration of the drug suspension . There were no significant differences, however, when the new treatment wa s compared with the control formulation consisting of simple enteric microp articles.