The present invention relates to biodegradable implantable medical device, in particular an endoprosthesis body formed at least partly from a constructional material comprising deformable super-pure magnesium or alloy thereof further comprising one or more super-pure alloying elements. The constructional material has a high formability at room temperature, excellent corrosion stability in vivo, an optimum combination of mechanical properties (strength, plasticity) ideally suited for biodegradable endoprosthesises, particularly stents, as such and for various other technical applications.
