Abstract: The size and location of microsphere uptake/delivery are important determinants of the final biodistribution of oral microsphere systems. Formulations, kits, methods of administering the formulations, and using the kits are described herein. The formulations are oral dosage formulations. In one embodiment, the formulations contain microparticles and/or nanoparticles having a homogenous size range selected to optimize uptake in a specific region of the GI tract and target drug delivery to specific organs. In some embodiments, the dosage formulation contains an enteric coating and/or a magnetic material. In a preferred embodiment, the formulation contains a magnetic material and an active agent to be delivered, optionally the active agent is in the form of micro- or nano-particles. In some embodiments metallomucoadhesive materials and/or magnetic materials are employed as magnetic and/or mucoadhesive sources.