Radiopaque polymers

A method of treatment in which a composition is administered into a blood vessel of a patient to embolize said blood vessel, the composition comprising (a) hydrogel in the form of microspheres comprising a cross-linked polymer network that comprises polyvinyl alcohol (PVA) or a copolymer of PVA and a radiopaque species comprising one or more covalently bound iodines that are coupled to the PVA or copolymer of PVA through a cyclic acetal group and that provides the microspheres with greater than 15 mg of iodine per ml of microspheres fully hydrated in normal saline as a packed volume and (b) a therapeutic agent, wherein the therapeutic agent is absorbed into the microspheres wherein the radiopaque species comprises an iodinated aromatic group.

A method of treatment in which a hydrogel is administered into a blood vessel of a patient to embolize said blood vessel, the hydrogel having a net charge at physiological pH in the form of microspheres having a mean diameter size range of from 10 to 2000 m and comprising a cross-linked polymer network that comprises polyvinyl alcohol (PVA) or a copolymer of PVA and a radiopaque species comprising an iodinated aromatic group that is coupled to the PVA or copolymer of PVA through a cyclic acetal group and that provides the microspheres with greater than 50 mg of iodine per ml of microspheres fully hydrated in normal saline as a packed volume.