pH triggered delivery of curcumin from Eudragit-coated chitosan microspheres for inflammatory bowel disease: characterization and pharmacodynamic evaluation

Objective: This investigation deals with the development and evaluation (in vitro and in vivo) of pH triggered Eudragit-coated chitosan microspheres of curcumin (CUR) for treating ulcerative colitis.

Methods: CUR-loaded chitosan microspheres were initially prepared by emulsion cross linking method followed by coating with Eudragit S-100. The pharmacodynamics of the developed formulation was analyzed in mice by acetic acid induced colitis model.

Results: The developed microspheres were of uniform spherical shape with high entrapment efficiency. CUR-chitosan microspheres showed less intense peaks compared to free CUR confirming inclusion of drug within microspheres as revealed by X-ray diffractogram. Uncoated CUR-chitosan microspheres exhibited burst release within initial 4?h while microspheres coated with Eudragit S-100 prevented premature release of CUR and showed controlled release up to 12?h following Higuchi model. In vivo organ biodistribution study showed negligible amount of CUR in stomach and small intestine confirming integrity of microsphere in upper gastrointestinal tract (GIT). In vivo study revealed significant reduction in severity and extent of colonic damage with CUR-loaded microspheres as compared to pure CUR which was further confirmed by histopathological study.

Conclusion: In vitro and in vivo studies proved the developed formulations as a promising system for pH-dependent delivery of drug to colon in ulcerative colitis.