Biodegradable, low biological toxicity radiographic contrast medium and method of x-ray imaging

The radiographic contrast medium of claim 24, wherein

• the polymer is selected from the group consisting of polyesters, polyamides, polycarbonates, polycarbamates and polyureas, derivatives thereof, analogues thereof, co-polymers thereof with other monomers and pharmaceutically acceptable salts thereof.

The biodegradable, low biological toxicity, particulate radiographic contrast medium of claim 24, wherein

• the average diameter of the spheres is about 50-500 nanometers.

The biodegradable, low biological toxicity, particulate radiographic contrast medium of claim 24, further comprising

• an additive selected from the group consisting of colorants, preservatives, stability enhancing agents, biological transport enhancing agents, suspending agents, osmotic agents and salts.

The biodegradable, low biological toxicity, particulate radiographic contrast medium of claim 24, wherein

• the radiographically opaque element is selected from the group consisting of iodine, bromine and lanthanides.

The biodegradable, low biological toxicity, particulate radiographic contrast medium of claim 24, wherein

• the radiographically opaque element is covalently bound to the polymer.

The biodegradable, low biological toxicity, particulate radiographic contrast medium of claim 24, wherein

• the radiographically opaque element is present in an amount of about 40 to 90 wt % of the polymer.

The biodegradable, low biological toxicity, particulate radiographic contrast medium of claim 24, consisting essentially of

• the biodegradable polymeric spheres.

An imaging composition, comprising

• a radiographically-detectable amount of the contrast medium of claim 24;
• and
• a carrier.