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.

Preparation and gamma scintigraphic evaluation of colon specific pellets of ketoprofen prepared by powder layering technology

BACKGROUND AND THE PURPOSE OF THE STUDY

Multiparticulates by powder layering process have advantages of the uniform distribution of the binder solution, easy-to-clean pan and the possibility of applying the successive functional film coating using the same equipment. This study relates to a multiparticulate formulation comprising pellets with a multilayer of pectin-ethyl cellulose on non pareil seeds by powder layering technology. The pellets were prepared to target ketoprofen in colon based on the microbial enzyme dependent drug release mechanism.

METHODS

Multiparticulate formulation by powder layering technology was prepared by conventional pan coating process to evaluate the effect of 59% methoxylated pectin and 45 cps ethyl cellulose on coating label. The formulations were tagged with (99m)Tc-DTPA, a tracer in gamma scintigraphy study to evaluate the transit behavior of drug loaded pellets and compared with uncoated pellets to evaluate its specific release.

RESULTS

The transit behavior and scintigraphy image clearly indicates that the formulation can delay the drug release prior to colon. In albino rabbit, the coated pellets released drug in the colon indicating that site specificity has been achieved with pectin/ethyl cellulose coating at 1:2 ratio with 20% coating label.

MAJOR CONCLUSION

Formulation containing pectin and ethyl cellulose with suitable coating label may be suitable as a coating formulation for colon delivery of ketoprofen and can be successfully evaluated by gamma scintigraphy method.