Drug-loaded microspheres have been caused much attention in embotherapy in recent years. In thlS StUdy, poiyvlnyi alcohol/acrylic acid microspheres were prepared by inverse suspension polymerization method. Sunitinih malate （SU） was used as a model drug and loaded on microspheres through ion-exchange mechanism. We investigated the characterization of blank microspheres （B-Ms） and sunitinib-loaded microspheres （SU-Ms） in vitro, including morphology, size distribution, equilibrium water content （EWC）, elasticity, drug loading and drug release. The result showed that both B-Ms and SU-Ms were spherical with smooth surface. The particle size of B-Ms and SU-Ms were both suitable for embolization. Compared with that of B-Ms, the EWC of SU-Ms was decreased and the rigidity of SU-Ms was increased. Drug loading and entrapment efficiency of microspheres were mainly affected by the concentration of sunitinib solution than by the size of microspheres. SU-Ms exhibited a sustained release in phosphate buffer solution （PBS）. Thus, the SU-Ms may have potential application for arterial embolization.
