#$%^&*AU2020204062A120200709.pdf#####ABSTRACT The present disclosure provides purified forms of iobenguane and preparations of a precursor to iobenguane, such as a polymer, the polymer comprising a monomer of formula (I) H2N NH NH (I) Sn H 3C CH 3 or a pharmaceutically acceptable salt thereof, the preparation comprising leachable tin at a level of 0 ppm to 850 ppm.