Abstract: OBJECTIVE To prepare sustained-release coated pellet containing clarithromycin, and to investigate its in vitro drug release behavior. METHODS Extrusion-spheronization technology was used to prepare clarithromycin-containing pellets. The drug contained pellets were coated with the optimized polymeric combination of Eudragit NE30D and Eudragit L30D-55 by using fluid-bed technology. In vitro drug release behavior of the coated pellets was studied and compared with the commercially available sustained-release capsules of clarithromycin. RESULTS There were no significant differences in different pH dissolution medium between the coated pellets and commercial products in drug release behavior, with optimized coating material as Eudragit NE30D and Eudragit L30D-55 at ratio of 5∶1. The drug release mechanism of coated pellets was in accordance with first-order release model. CONCLUSIONS With extrusion- spheronization and fluid-bed technology, the sustained-release coated pellets containing clarithromycin are successfully prepared by using the mixture aqueous dispersion of Eudragit NE30D and Eudragit L30D-55 as coating material.