The present invention features compositions and methods for targeted delivery of a therapeutic or imaging agent to a site accessible through the nose or mouth that may be difficult to effectively and efficiently treat otherwise (e.g., the middle ear, sinuses, or lung). The therapeutic or imaging agent is deposited onto a magnetic nanoparticle that is drawn through a passage or tissue that leads away from the nose or mouth by a magnetic field applied over the targeted site (e.g., by magnets within the ear canal or surrounding the ear).