Syringe Assembly Having a Rotatably Advanceable Plunger Rod

Abstract

A syringe assembly for use as a pre-filled syringe is disclosed. The syringe assembly includes a syringe barrel defining a chamber and having a stopper disposed therein. A plunger rod includes an inner member engaged with a portion of the stopper and an outer member adapted for rotational advancement with respect to the inner member to axially displace the outer member with respect to the inner member. The plunger rod is transitionable from a collapsed position in which a portion of the inner member is nested within the outer member, to an extended position in which the same portion of the inner member extends outside the outer member. The inner member includes a radial extension and the outer member defines a helical track adapted to receive the radial extension therein.

What is claimed is: 
     
         1 . A syringe assembly, comprising:
 a syringe barrel having a first end, a second end, and a sidewall extending therebetween defining a chamber;   a stopper slideably disposed at least partially within the chamber; and   a plunger rod having an inner member engaged with a portion of the stopper and an outer member adapted for rotational advancement with respect to the inner member to axially displace the outer member with respect to the inner member,   wherein the plunger rod is transitionable from a collapsed position in which a portion of the inner member is nested within the outer member, to an extended position in which the same portion of the inner member extends outside the outer member.   
     
     
         2 . The syringe assembly of  claim 1 , wherein the inner member comprises a radial extension and the outer member defines a track adapted to receive the radial extension therein. 
     
     
         3 . The syringe assembly of  claim 2 , wherein the track is at least partially helical about an outer surface of the outer member. 
     
     
         4 . The syringe assembly of  claim 2 , wherein the radial extension remains substantially stationary during transition of the plunger rod from the collapsed position to the extended position. 
     
     
         5 . The syringe assembly of  claim 4 , wherein the outer member is rotated about the inner member to axially displace the outer member with respect to the inner member. 
     
     
         6 . The syringe assembly of  claim 2 , wherein the track extends between a proximal end and a distal end, the distal end comprising a restraint for locking the radial extension therein in the extended position. 
     
     
         7 . The syringe assembly of  claim 1 , wherein the stopper remains substantially stationary during transition of the plunger rod from the collapsed position to the extended position. 
     
     
         8 . The syringe assembly of  claim 1 , further comprising a medication or drug disposed within the chamber. 
     
     
         9 . A plunger rod assembly comprising a plunger rod for use with a syringe assembly, the plunger rod comprising:
 an inner member having a distal end configured for securement to a stopper disposed within a syringe barrel;   an outer member having an open portion configured for rotational advancement with respect to the inner member to axially displace the outer member with respect to the inner member, wherein the plunger rod is transitionable from a collapsed position in which a portion of the inner member is nested within the outer member, to an extended position in which the same portion of the inner member extends outside the outer member; and   a restraint configured to limit axial advancement of the outer member with respect to the inner member in the extended position.   
     
     
         10 . The plunger rod assembly of  claim 9 , wherein the restraint is configured to limit axial advancement of the outer member in both a proximal direction and a distal direction in the extended position. 
     
     
         11 . The plunger rod assembly of  claim 9 , wherein the inner member comprises a radial extension and the outer member defines a track adapted to receive the radial extension therein. 
     
     
         12 . The plunger rod assembly of  claim 11 , wherein the track is at least partially helical about an outer surface of the outer member. 
     
     
         13 . The plunger rod assembly of  claim 11 , wherein the radial extension remains substantially stationary during transition of the plunger rod from the collapsed position to the extended position. 
     
     
         14 . The plunger rod assembly of  claim 11 , wherein the track extends between a proximal end and a distal end, the distal end comprising the restraint wherein the restraint locks the radial extension therein in the extended position. 
     
     
         15 . A syringe assembly, comprising:
 a syringe barrel having a first end, a second end, and a sidewall extending therebetween defiling a chamber;   a stopper slideably disposed at least partially within the chamber; and   a plunger rod comprising:
 an inner member engaged with a portion of the stopper and comprising a radial extension; and 
 an outer member defining a track adapted to receive the radial extension therein, 
   wherein rotation of the outer member about the inner member axially displaces the track about the radial extension to transition the plunger rod from a collapsed position in which a portion of the inner member is nested within the outer member, to an extended position in which the same portion of the inner member extends outside the outer member.   
     
     
         16 . The syringe assembly of  claim 15 , wherein the track is at least partially helical about an outer surface of the outer member. 
     
     
         17 . The syringe assembly of  claim 15 , wherein an initial portion of the inner member and an initial portion of the outer member are disposed within the syringe barrel in the collapsed position. 
     
     
         18 . The syringe assembly of  claim 17 , wherein the initial portion of the outer member is external to the syringe barrel in the extended position. 
     
     
         19 . The syringe assembly of  claim 15 , wherein the track extends between a proximal end and a distal end, the distal end comprising a restraint for locking the radial extension therein in the extended position. 
     
     
         20 . The syringe assembly of  claim 15 , further comprising a medication or a drug disposed within the chamber of the syringe barrel.