| abstract |
An implant, usually a stent, has a coating of a cross-linked water swellable polymer matrix preferably having a dry thickness of at least 0.1 μm, and a pharmaceutically active compound, the polymer having pendant cationic and pendant zwitterionic groups. The active is usually an anionic compound such as a nucleic acid. The polymer is peferably formed from 2-methacyloy-loxyethyl-2′-trimethylammoniumethyl phosphate inner salt, trialkylammoniumalkyl(meth)acrylate and a cross-linkable monomer such as ω-(trialkoxysilyl)alkyl(meth)acrylate, optionally with a termonomer such as a higher alkyl (meth)acrylate. The stent is coated with polymer, cross-linked then contacted with a solution or dispersion of active compound in a solvent which swells the polymer whereby the active is absorbed into the polymer matrix. The stent is delivered by usual means into a body lumen and the actives released over an extended period of time into the wall of the lumen and/or fluid flowing therein. |