Objective:To determine the in vitro release of two kinds of
Changankang Pellets (Radix Astragall, Rhizama coptid) coated
with Surelease and Eudragit respectively and verify their
colon-targeted release in vivo through X-ray photography. Methods:
Changankang Pellets were made by mixing the medical BaSO 4 powder and appropriate drugs together according to original produce and coat methods. After determining their in vitro release, they were tested in vivo by 2 volunteers. X-ray films were taken after appropriate time and analyzed to determine the location and status of these pellets inside healthy objects. Results: Pellets made by this way can carry drugs through stomach, intestine and targeted-release them in colon; the coating combined with pH-dependent and time-dependent Eudragit thin layer has better results. Conclusion: X-ray radiography applying BaSO 4 powder could be taken as a quality control method for colon-targeted release drugs. The preliminary results showed that Changankang Pellets met the requirements of colon-targeted release.