| Magnetic targeted drugs (MTD) could effectively limit the side effects of chemotherapeutic drug by limiting the amount of drug administered as well as improving its effect. Therefore MTD exhibits a prosperous future in the field of cancer treatment. In this paper, the preparation of MTD and its current studies were reviewed, and the preparing methods of nanosized Fe3O4 were introduced in detail as well.Chemical co-precipitation method was adopted to prepare nanosized Fe3O4 with FeSO4·(NH4)2SO4·6H2O, NH4Fe(SO4)2·12H2O, NH4OH and PEG4000 as the raw materials. Simple methods were designed to measure magnetism, magnetic response and suspension stability. The influence of preparation conditions to the properties of nanosized Fe3O4 was studied in a series of conditional experiments. These conditions included material feeding, alkali, pH value, stirring method and rate, concentration of Fe and Fe2+/Fe3+, surfactant and its amount, temperature and aging time, additive and magnetic field, et al. A L16(46) orthogonal test was adopted to optimize the preparation technology. The result indicates that the sequence of the influence of preparation conditions to the properties of nanosized Fe3O4 is: reaction temperature>pH value> Fe2+/Fe3+>aging time> stirring rate> the amount of PEG4000. The ideal technical process is: mechanical stirring and ultrasonic stirring were used in alternation and the deposit was aged for 30min at 60 ℃ with pH in the range of 9-10, the concentration of Fe being 0.1mol/L, Fe2+/Fe3+=1:1, the amount of PEG4000 being 0.77g (mFe3O4/mPEG4000=1: 1), stirring rate being 1000r/min and the reaction temperature at 60 ℃. The structure and size of as-obtained Fe3O4 was investigated by means of XRD and TEM. The results indicated that most of the products were cubic crystal Fe3O4, but a little FeOOH were found in the products as well, and the size was in the range of 2040nm. The composition of the product was investigated with chemical analytic method and the ratio of Fe3+/Fe2+ was found to be 1.9:1<2:1, which indicated that there existed other crystal except Fe3O4. Magnetic fluid with excellent properties was obtained after the re-encapsulation of the nanosized Fe3O4 with sodium dodecyl benzene sulfonate (SDBS). No deposit was found in a week, and the magnetic response was found 56s and the magnetism 200×10-4g/(2cm·0.05g magnetic powder) in the thus-obtained magnetic fluid.
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