Patent ID: 8318209

Claim:
A porous non-degradable particle for use in a therapeutic and/or diagnostic procedure, the porous non-degradable particle comprising: a core comprising a hydrogel formed from acrylic-based polymers derived from mono-functional acrylic-based monomer units forming the backbone of the hydrogel polymers and multi-functional monomer units forming covalent cross-links within the hydrogel polymers; and an outer coating comprising poly[bis(trifluoroethoxy) phosphazene] derivative of formula (I) wherein n is at least 100; and each R 1 to R 6 is, independently, trifluorethoxy, ethoxy, pentafluoropropyloxy, hexafluoroisopropyloxy, heptafluorobutyloxy, tridecafluorooctyloxy, tetrafluoropropyloxy, hexafluorobutyloxy, dodecafluorooctyloxy, or alkenoxy, wherein the diameter of the porous non-degradable particle is at least 40 μm to 5,000 μm; and wherein the core is surrounded by an inner coating of barium sulfate and the outer coating surrounds the inner coating of barium sulfate.