Patent ID: 7354605

Claim:
A medical device having antimicrobial properties, said medical device having been made from or coated with an antimicrobial polymer composition comprising a hydrophobic matrix polymer and an antimicrobial additive dispersed therein wherein the antimicrobial additive is in the form of discrete particles of a water absorbing, water vapor absorbing and wettable hydrophilic polymer having encapsulated therein or dispersed therein one or more particles of at least one antimicrobial metal or metal ion containing inorganic antimicrobial agent, said antimicrobial agent being capable of releasing said antimicrobial metal or metal ion during use of said medical device and said hydrophilic polymer having a water absorption at equilibrium of at least 20% by weight, and wherein said discrete particles of the antimicrobial additive have a mean average diameter of greater than 2 Î¼ and less than about 300 Î¼; provided that when the antimicrobial additive is of a core-shell type configuration comprising the antimicrobial agent as the core and the hydrophilic polymer as the encapsulating coating, the thickness of the hydrophilic polymer coating encapsulating the antimicrobial agent is from about 1 Î¼ to about 15 Î¼ and, when the antimicrobial additive is in the form of hydrophilic polymer particles having dispersed therein multiple particles of the antimicrobial agent, the antimicrobial additive comprises 100 parts by weight of the hydrophilic polymer and from 1 to 1000 parts by weight of the antimicrobial agent.