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 pectinethyl 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 99mTc-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.