Abstract: OBJECTIVE To prepare antitubulin SUD-35 solid dispersion from poorly-soluble SUD-35 so as to improve its solubility and dissolution rate in vitro. METHODS Solid dispersions of SUD-35 were prepared by solvent-fusion method with PEG6000 as carrier. The status of SUD-35 in carrier was determined by differential scanning calorimetry(DSC) and X-ray diffractometry(XRD). The solubility and the dissolution rate of the solid dispersion in vitro were studied. The cytotoxicities of SUD-35 in solid dispersion to the L1210 cells were assayed by MTT method. RESULTS The results showed that the solubility and dissolution rate of SUD-35 was significantly improved by solid dispersion compared to that of the pure drug and physical mixture. The results of DSC and XRD showed that the SUD-35 insolid dispersion was amorphous form. Cytotoxicity study suggested that the inhibitory rates of SUD-35-PEG6000 solid dispersion to L1210 cells were higher than that of pure SUD-35. CONCLUSION The solubility and dissolution rates of SUD-35 were improved by solid dispersion technique.