The Fe3O4-poly(L-lactide) (Fe3O4-PLLA) magnetic microparticles Were successfully prepared in a process of solution-enhanced dispersion by supercritical CO2 (SEDS), and their morphology, particle size, magnetic mass content, surface atom distribution and magnetic properties were characterized. Indomethacin (Indo) was used as a drug model to produce drug-polymer magnetic composite microparticles. The resulting Fe3O4-PLLA microparticles with mean size of 803 run had good magnetic property and a saturation magnetization of 24.99 emu/g. The X-ray photoelectron spectroscopy (XPS) test indicated that most of the Fe3O4 were encapsulated by PLLA, which indicated that the Fe3O4-PLLA magnetic microparticles had a core-shell structure. After further loading with drug, the Indo-Fe3O4-PLLA microparticles had a bigger mean size of 901 nm, and the Fourier transform infrared spectrometer (FTIR) analysis demonstrated that the SEDS process was a typical physical coating process to produce drug-polymer magnetic composite microparticles, which is favorable for drugs since there is no change in chemistry, The in vitro cytotoxicity test showed that the Fe3O4-PLLA magnetic microparticles had no cytotoxicity and were biocompatible, which means there is potential for biomedical application. (c) 2008 Elsevier Inc. All rights reserved.