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This paper describes an in vitro method to characterize the efficiency of a setup for magnetic drug targeting. The simple flow phantom includes a peristaltic pump propelling a magnetic nanoparticle (MNP) suspension through a tubing system. A magnet placed at a specific location at the tubing retained particles due to magnetic forces. The accumulated MNP concentration was quantified using magnetic particle spectroscopy (MPS) allowing the detection of small changes in MNP concentration. The system was tested with MNPs of three different mean hydrodynamic diameters suspended in bovine serum albumin and blood. We found a retention yield crucial depending on the hydrodynamic diameter. For MNPs with 50 nm mean hydrodynamic diameter no retention was observed, whereas MNPs with a mean hydrodynamic diameter of 330 nm were accumulated most efficiently, but already showed a slight aggregation tendency. In addition to the quantification of MNP retention, MPS allowed the detection of changes in size distribution as a consequence of the targeting process. These changes were confirmed in more detail using magnetorelaxometry.

Due to its high targeting efficiency magnetic drug targeting has been proposed as a promising technique for tumor treatment. Since drug-loaded nanoparticles are concentrated within a target region due to the influence of a magnetic field unwanted side effects are considerably reduced. In a first step to contribute to the understanding of basic phenomena experiments on a half-Y-branched glass tube model as a model-system for a blood vessel supplying a tumor were performed. The results of those systematic quantitative measurements were summarized in novel drug-targeting maps. Based on the considered setup and artery-model the current focus is a theoretical approach with a finite-element simulation. The fluid flow is described by the Navier-Stokes equations, the mass flux is given by the advection-diffusion equation and the magnetic field is derived from Maxwell's equations. The magnetic volume force acting on a volume of magnetic fluid combines the magnet and the ferrofluid data and is proportional to the field dependent magnetisation and the gradient of the field strength. The diffusion equation additionally allows the implementation of a concentration-dependent magnetic volume force. Our experimental investigations have shown that the miscibility of even the water-based ferrofluid and water is low. Since in medical applications the ferrofluid will be injected close to an appropriate junction one cannot necessarily assume a homogeneous mixture approaching the branch-region. Therefore, the characteristic focus of the presented simulation is a model where at the point of injection the ferrofluid and the carrier-fluid are initially separated and further mixture occurs due to the velocity field, diffusion, volume forces and magnetophoresis.

Magnetic drug targeting (MDT) has been established as a promising technique for tumour treatment. Due to its high targeting efficiency unwanted side effects are considerably reduced, since drug-loaded nanoparticles are concentrated within a target region due to the influence of a magnetic field. This work presents experimental results that are based on systematic quantitative measurements on a branched tube model as a model system for a blood vessel supplying a tumour. The systematic measurements are summarized in novel drug targeting maps, combining e.g. the net amount of targeted nanoparticles, the magnetic volume force and also the position of the magnet. The model, the injection procedure and the ferrofluid are chosen close to the parameters of a medical application. This will allow transfer of the results to future medical investigations. This work will present a targeting map, where the concentration of the injected ferrofluid is in the range of experiments with an ex vivo bovine artery model.