Plunger covers and plungers for use in syringes

Abstract

A plunger cover for use with a syringe includes a sealing portion adapted to form a seal with the syringe and a central portion adapted to contact fluid within the syringe. The central portion can, for example, be more rigid than the sealing portion. The sealing portion and the central portion are connected in an overmolding process. The sealing portion can, for example, be formed from a thermoplastic elastomer or a thermoplastic polyurethane. The central portion can, for example, be formed from polypropylene, acrylonitrile butadiene styrene, polycarbonate or copolymers thereof.

What is claimed is: 
     
         1 . A plunger for use with a syringe comprising:
 a plunger cover comprising a sealing portion adapted to form a seal with the syringe and a central portion adapted to contact a fluid within the syringe, the central portion being more rigid than the sealing portion, the sealing portion and the central portion being connected in an overmolding process; and   the sealing portion is formed or molded from an elastomeric material;   the sealing portion includes a seating; and   wherein the seating is configured to connect to a drive member on an injector to which the syringe is attached.   
     
     
         2 . The plunger of  claim 1  wherein the seating comprises a threaded seating. 
     
     
         3 . The plunger of  claim 1  wherein the elastomeric material is one of thermoplastic elastomer and thermoplastic polyurethane. 
     
     
         4 . The plunger of  claim 1 , wherein a material for the sealing portion is a first material and a material for the central portion is a second material, the first material and the second material are different and are selected so that molecular bonding occurs between the sealing portion and the central portion.