Evaluation of the tolerance and distribution of intravenously applied ferrofluid particles of 250 and 500 nm size in an animal model.

OBJECTIVE: Magnetic drug targeting may be a new method for the treatment of malignant tumors. According to the previous investigations, the success of magnetic targeting is generally contingent upon the magnetic properties and size distribution of the magnetic nanoparticles. Therefore, the aim of the present study was to verify the tolerance of two ferrofluid dispersions modified in particle size and density.
MATERIALS AND METHODS: 8.75 ml ferrofluid with particle sizes of 250 or 500 nm were applied intravenously to two groups of seven New Zealand White rabbits in three doses in a time frame of 2 h. Clinical, serological,and histological evaluations were performed with regard to the tolerance of the ferrofluids.
RESULTS: All animals tolerated the ferrofluid application without any clinical irregularities; there were no signs of thrombosis or embolism. Histological analysis revealed an accumulation in the liver, spleen, lung, and kidney depending on the particle size; the serological examination did not show significant alterations of the blood parameters.
CONCLUSION: The ferrofluids of 250 and 500 nm particle sizes were well tolerated as shown by the laboratory and histological data and should be evaluated in further studies regarding their clinical use in magnetic drug targeting.