Magnetic guidance of drug-carrying microspheres

Abstract

Physical laws underlying the intravascular magnetic guidance of a novel drug carrier are discussed. The drug carrier is a magnetically responsive drug-bearing microsphere measuring approximately 1 μm in diameter. The microspheres consist of an albumin matrix in which a prototype drug (adriamycin HCl) and ultrafine Fe3O4 particles are entrapped. An in vitro analog of the human circulatory system is used to test both bipolar and unipolar magnetic arrangements which can retain microspheres flowing in aqueous suspension in the area of applied magnetic field. Retention of the microspheres by the magnetic field is shown to vary with the linear velocity of the viscous suspending medium and to be dependent on the magnitude of the applied magnetic force. This system permits extracorporeal control over the distribution of intravascular soluble chemotherapeutic agents and allows their concentration at specified body sites.