Mixing syringe assembly

Abstract

A syringe assembly comprising a barrel for containing one or more medicaments, the barrel having a front outlet for allowing the expulsion of said one or more medicaments from the said barrel through said outlet, and a first stopper disposed in the barrel and axially moveable therein and defining a first volume in the barrel axially forwards of the first stopper and a second volume in the barrel axially rearwards of the first stopper. The first stopper has a two way valve that is moveable between a sealing configuration and an open configuration to selectively put the first volume in fluid communication with the second volume. The two way valve is moveable from the sealing configuration to the open configuration by an increase in fluid pressure in either of the first and second volumes. The syringe assembly additionally comprises a second stopper disposed in the barrel axially rearward of the first stopper and axially moveable therein, the second stopper providing a fluid tight seal at a rear end of the second volume. The syringe assembly further comprises a first plunger rod connected to the first stopper and extending axially rearwardly through the second stopper, the second stopper sealingly engaging with the first plunger rod but permitting axial sliding of the first plunger rod therethrough. The first plunger rod is axially moveable so as to axially move the first stopper and pressurise either of the first volume and second volume causing the two way valve to move into the open configuration and fluidly connect the first volume and second volume.

1 . A syringe assembly comprising:
 a barrel for containing one or more medicaments, the barrel having a front outlet for allowing the expulsion of said one or more medicaments from said barrel through said outlet;   a first stopper disposed in the barrel and axially moveable therein, the first stopper having a two way valve that is moveable between a sealing configuration and an open configuration;   a second stopper disposed in the barrel axially rearward of the first stopper and axially moveable therein, the second stopper providing a fluid tight seal to the barrel; and   a first plunger rod connected to the first stopper and extending axially rearwardly through the second stopper, the second stopper sealingly engaging with the first plunger rod but permitting axial sliding of the first plunger rod therethrough;   wherein the first plunger rod is axially moveable in the barrel so as to axially move the first stopper from an initial position to a subsequent position, wherein in the subsequent position a first volume is defined in the barrel axially forwards of the first stopper and a second volume is defined in the barrel axially rearwards of the first stopper, and in the initial position either of the first volume or second volume is a substantially zero volume, wherein axial movement of the first stopper in the barrel pressurises either of the first volume and second volume causing the two way valve to move into the open configuration and fluidly connect the first volume and the second volume.   
     
     
         2 . A syringe assembly according to  claim 1 , further comprising a removeable transit clip that is configured to prevent axial movement of the first plunger rod. 
     
     
         3 . A syringe assembly according to  claim 1 , wherein the first plunger rod includes one or more finger loops for facilitating handling of the first plunger rod. 
     
     
         4 . A syringe assembly according to  claim 1 , further comprising a second plunger rod connected to the second stopper, wherein axial movement of the second plunger rod causes axial movement of the second stopper. 
     
     
         5 . A syringe assembly according to  claim 4 , further comprising an engagement mechanism for engaging the first plunger rod with the second plunger rod in a predetermined position of the first plunger rod relative to the second plunger rod. 
     
     
         6 . A syringe assembly according to  claim 5 , wherein the engagement mechanism includes engagement members connected to the first plunger rod, the engagement members being arranged to engage with the second plunger rod when the first plunger rod is at a predetermined axial position and/or rotational position relative to the second plunger rod. 
     
     
         7 . A syringe assembly according to  claim 6 , wherein said engagement members project radially inwardly from a sleeve connected to the first plunger rod and surrounding the second plunger rod. 
     
     
         8 . A syringe assembly according to  claim 6 , wherein said engagement members are arranged to engage with a rear end of the second plunger rod by abutting said rear end of said second plunger rod. 
     
     
         9 . A syringe assembly according to  claim 4 , further comprising a locking mechanism for limiting axial movement of the second plunger rod. 
     
     
         10 . A syringe assembly according to  claim 9 , wherein axial movement of the second plunger rod is permitted when the second plunger rod is in a predetermined rotational position. 
     
     
         11 . A syringe assembly according to  claim 10 , wherein the locking mechanism comprises a collar and axial movement of the second plunger rod is permitted when the second plunger rod is in a predetermined rotational position relative to the collar and axial abutment between the collar and the second plunger rod prevent relative axial movement in rotational positions other than the predetermined rotational position. 
     
     
         12 . A syringe assembly according to  claim 1 , wherein the two way valve comprises a resilient seal that deforms under a predetermined fluid pressure. 
     
     
         13 . A syringe assembly according to  claim 12 , wherein the resilient seal includes a plurality of flexible flaps. 
     
     
         14 . A syringe assembly according to  claim 12 , wherein the resilient seal extends along an arc around the first stopper, wherein the angular extent of the arc is less than 360°. 
     
     
         15 . A syringe assembly according to  claim 12 , wherein the first stopper includes the resilient seal and further includes a permanent seal about an outer circumference of the first stopper that is axially spaced from the resilient seal, and a by-pass channel providing a fluidic passageway from between the resilient seal and the permanent seal around the permanent seal. 
     
     
         16 . A syringe assembly according to  claim 1 , wherein the fluid tight seal provided by the second stopper is a sterile seal. 
     
     
         17 . A syringe assembly according to  claim 1 , wherein the fluid tight seal provided by the second stopper is a microbiological seal. 
     
     
         18 . A syringe assembly according to  claim 1 , further comprising a medicament, wherein when the first stopper is in the initial position the medicament is contained only in the one of the first volume and the second volume that is not the substantially zero volume. 
     
     
         19 . A method of using a syringe assembly that comprises:
 a barrel for containing one or more medicaments, the barrel having a front outlet for allowing the expulsion of said one or more medicaments from said barrel through said outlet;   a first stopper disposed in the barrel and axially moveable therein, the first stopper having a two way valve that is moveable between a sealing configuration and an open configuration;   a second stopper disposed in the barrel axially rearward of the first stopper and axially moveable therein, the second stopper providing a fluid tight seal to the barrel; and   a first plunger rod connected to the first stopper and extending axially rearwardly through the second stopper, the second stopper sealingly engaging with the first plunger rod but permitting axial sliding of the first plunger rod therethrough;   the method comprising axially moving the first plunger rod in the barrel so as to axially move the first stopper from an initial position to a subsequent position, wherein in the subsequent position a first volume is defined in the barrel axially forwards of the first stopper and a second volume is defined in the barrel axially rearwards of the first stopper, and in the initial position either of the first volume or second volume is a substantially zero volume and the other of the first volume and the second volume contains the one or more medicaments, wherein axial movement of the first stopper in the barrel pressurises either of the first volume and second volume causing the two way valve to move into the open configuration and fluidly connect the first volume and the second volume.