Patent ID: 7811601

Claim:
A drug delivery ophthalmic lens comprising a cationic group-containing drug in the inside of a copolymer, wherein the copolymer consists of: (a) a hydrophilic monomer having a hydroxyl group in its molecule; (b) at least one phosphate group-containing methacrylate represented by the following structural formula (I), (c) a monomer having a nitrogen atom in its side chain; and (d) a monomer copolymerizable with (a), (b) and (c), wherein a mixture of the following structural formulae (II) and (III) is used as the phosphate group-containing methacrylates: wherein the monomer having a nitrogen atom in its side chain is (meth)acrylamide and the copolymer contains anionic monomers in a ratio of 30 mol % to 90 mol % to the cationic monomer.