Systems and methods for magnetic targeting of therapeutic particles are provided. Therapeutic particles comprise one or more magnetic or magnetizable materials and at least one therapeutic agent. Therapeutic particles are specifically targeted using uniform magnetic fields capable of magnetizing magnetizable materials, and can be targeted to particular locations in the body, or can be targeted for capture, containment, and removal. Also provided are bioresorbable nanoparticles prepared without the use of organic solvents, and methods for therapeutically using such bioresorbable nanoparticles.