By tuning the contents of magnesium ferrite, a series of magnetic nanoparitcles based on layered double hydroxide (LDH) for magnetic drug targeting were prepared via a one step coprecipitation method. The microstructure, thermal stability, magnetism and drug release properties of these magnetic nanoparitcles were systematically investigated. It is found that the magnetic nanoparticles possess core-shell structure with diclofenac intercalated LDH (DIC-LDH) shell coated on the surface of magnesium ferrite core. The Scherrer particle size and the layer charge density of the coated DIC-LDH, the drug loading of the magnetic nanoparticles decrease gradually with increasing magnesium ferrite content, while their saturation magnetizations show the inverse trend. Under no magnetic field (MF), the magnetic nanoparticles show enhanced drug release rate with increasing magnesium ferrite content due to the decreased particle size of the coated DIC-LDH. Under a 1500 G MF, the release rate reduces gradually with increasing magnesium ferrite contents due to the instantly aggregation of the magnetic nanoparticles induced by the MF.

Key words: magnetic nanoparticles, layered double hydroxide, in vitro drug release, magnesium ferrite, magnetic field, diclofenac