Patent ID: 6544233
Filing Date: 2003-04-08
Classification: A61M

Abstract:
A pre-filled syringe comprising:an outer cylinder having a nozzle, at a front end thereof, sealed with a sealing member or a closed end and an opening formed at a rear end thereof; an inner cylinder movable forward and rearward in said outer cylinder, forming a first space between said inner cylinder and an inner side of said front end of said outer cylinder, and having an opening formed at each of the front and rear ends thereof; a first gasket slidably accommodated in said inner cylinder in a liquid-tight state; a second gasket accommodated slidably in said inner cylinder in a liquid-tight state and located rearward from said first gasket and forming a second space between said second gasket and said first gasket; a plunger attached or attachable at a rear end of said second gasket; a third gasket installed at said front end of said inner cylinder or in the vicinity of said front end thereof such that the third gasket is slidable in a liquid-tight state between said inner cylinder and said outer cylinder; a first medicine stored in said first space; and a second medicine stored in said second space, wherein said inner cylinder has a portion, formed at said front end thereof, for preventing said first gasket from slipping off from said opening formed at said front end of said inner cylinder; and a rib and/or a groove extending from an inner side surface of said front end of said inner cylinder in an axial direction of said inner cylinder to form a medicine duct for introducing said second medicine into said first space, when said first gasket moves to said front end of said inner cylinder; and said inner cylinder moves automatically toward said rear end of said outer cylinder owing to rise of a pressure inside said first space caused by a flow of said second medicine into said first space which occurs as a result of a movement of said second gasket and a movement of said first gasket to said front end of said inner cylinder caused by a pressing force applied to said second gasket, said inner cylinder and said plunger having an engaging mechanism, respectively such that said engaging mechanisms engage each other when said plunger attached on said second gasket is pressed into said inner cylinder to such an extent that said plunger cannot be moved forward further therein and prevent rearward movement of said plunger.