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Controlling the path of drugs movement is one of the processes that can effectively help to treat a variety of diseases. For example, in chemotherapy, small fraction of drug is delivered to the cancer cells and other amounts cause destruction of healthy tissues of body, as a result, before destruction of tumors, the body will be destroyed. Hence we cannot remove tumors from body completely. If we are able to control the path of drugs, we could remove tumors with the least injury. One of the ways through which we can control the movement of the drugs is MDT. In this project, we inspect movement of magnetic particles in the blood and their interactions with consideration of constant magnetic field gradient. After governing its equations and presenting a good model for the forces between particles we simulate these processes in the fluent software. The model we used here is a vein with 8 mm diameter. The simulation was done over 8 cm length of the vein, and from the moment of injection. The base fluid is blood which is considered none-Newtonian fluid. Distribution of magnetic particles in the base fluid has been governed by multiphase approach. The simulation results show that residence time of drug in the presence of magnetic field, increases which in turn increases the possibility of drug absorption.