The dissolution characteristics of DDB were markedly enhanced by preparing solid dispersions of drug with polyethylene glycol 6000. Solid dispersions of various weight fraction were formed by a melting method. And various tablets$(A{sim}E)$ were prepared from these solid dispersions with excipients (lactose, com starch, Avicel and PVP) by wet granulation method. There were no significant differences in dissolution rates between physical mixture and DDB alone. But dissolution rates of solid dispersions were $1.4{sim}2.0$ times greater than that of DDB alone and $1.2{sim}1.8$ times greater than those of a commercial tablet.