| abstract |
An insoluble polymer is deposited in a body cavity for instance to embolize a vein or pack an aneurysm, the polymer having pendant zwitterionic groups to improve biocompatibility. The insoluble polymer is preferably formed by an in situ gelling step in which a charged, preferably soluble, polymer having pendant zwitterionic groups is introduced in the form of a composition in which it is soluble and is gelled by being mixed with a counterionically charged soluble polymer (polyelectrolyte), to form a polyion complex. Preferably the or each soluble polymer is formed by polymerizing ethylenically unsatured monomers including a zwitterionic monomer, for instance 2-methacryloyloxyethyl-2'-trimethylammoniumethyl phosphate inner salt, an ionic monomer such as trimethylammonium alkyl(alk)acrylate or a sulphoalkyl(alk)acrylate and optionally a diluent monomer such as an alkyl(alk)acrylate. |