Patent ID: 6817990
Filing Date: 2004-11-16
Classification: A61M,Y10S

Abstract:
An apparatus for dispensing a medication fluid comprising:a reservoir adapted to contain the fluid and adapted for use with a drive system having a threaded linear actuation member; and a piston comprising: a first member adapted to be slidably mounted within the reservoir and adapted to form at least part of a fluid-tight barrier within the reservoir; the first member having an external proximate side and an external distal side, the external proximate side being adapted to contact the fluid and being made of a material having a first stiffness, and wherein the external distal side forms an opening leading to a cavity and includes threads adapted to releasably engaged the threaded linear actuation member; a second member having a first side and a second side, at least a portion of the second member being disposed within the cavity of the first member; and the first side of the second member being in the cavity and adjacent to the external proximate side of the first member and being made of a material having a stiffness which is greater than the first stiffness; and the second member further including one or more passages through the second member from the first side to the second side of the second member to permit admittance of a sterilization agent to the first side of the second member.