Syringe

Abstract

The invention provides a syringe for use in an ophthalmic injection. The syringe comprises a body, a stopper and a plunger. The body comprises an outlet at an outlet end and the stopper is arranged within the body such that a front surface of the stopper and the body define a variable volume chamber from which a fluid can be expelled though the outlet. The plunger comprises a plunger contact surface at a first end and a rod extends between the plunger contact surface and a rear portion. The plunger contact surface is arranged to contact the stopper but not couple thereto, such that the plunger can be used to force the stopper towards the outlet end of the body, reducing the volume of the variable volume chamber, but not to move the stopper away from the outlet end.

1 . A syringe, the syringe ( 1 ) comprising a body ( 2 ), a stopper ( 10 ) and a plunger ( 4 ), the body ( 2 ) comprising an outlet ( 12 ) at an outlet end ( 14 ) and the stopper ( 10 ) being arranged within the body ( 2 ) such that a front surface ( 16 ) of the stopper ( 10 ) and the body ( 2 ) define a variable volume chamber ( 18 ) from which a fluid ( 20 ) can be expelled though the outlet ( 12 ), the plunger ( 4 ) comprising a plunger contact surface ( 22 ) at a first end ( 24 ) and a rod ( 26 ) extending between the plunger contact surface ( 22 ) and a rear portion ( 25 ), characterized in that the stopper ( 10 ) provides a sealing function by defining the rear of the variable volume chamber ( 18 ) with a fluid tight seal and the plunger contact surface ( 22 ) arranged to contact the stopper ( 10 ) but not couple thereto, such that the plunger ( 4 ) can be used to force the stopper ( 10 ) towards the outlet end ( 14 ) of the body ( 2 ), reducing the volume of the variable volume chamber ( 18 ), but not to move the stopper ( 10 ) away from the outlet end ( 14 ) 
     
     
         2 . A syringe as claimed in  claim 1 , in which the plunger contact surface ( 22 ) is a substantially planar disc and the plunger contact surface ( 22 ) contacts a rear surface ( 60 ) of the stopper ( 10 ). 
     
     
         3 . A syringe as claimed in  claim 1  in which the rod ( 26 ) comprises at least one rod shoulder ( 32 ) directed away from the outlet end ( 14 ) and the syringe ( 1 ) includes a backstop ( 6 ) arranged at a rear portion of the body ( 2 ), the backstop ( 6 ) including a backstop shoulder ( 34 ) directed towards the outlet end ( 14 ) to cooperate with the rod shoulder ( 32 ) to substantially prevent movement of the plunger rod ( 26 ) away from the outlet end ( 14 ) when the backstop shoulder ( 34 ) and rod shoulder ( 32 ) are in contact. 
     
     
         4 . A syringe as claimed in  claim 3 , in which the rod shoulder ( 32 ) is arranged within the external diameter of the rod ( 26 ). 
     
     
         5 . A syringe as claimed in  claim 3 , in which the rod shoulder ( 32 ) comprises a substantially disc shaped portion on the rod ( 26 ). 
     
     
         6 . A syringe as claimed in  claim 3 , in which the backstop ( 6 ) is removable from the syringe ( 1 ). 
     
     
         7 . A syringe as claimed in  claim 6 , in which the backstop ( 6 ) is configured to substantially sandwich terminal flanges of the body ( 2 ). 
     
     
         8 . A syringe as claimed in  claim 3 , in which, when arranged with the plunger contact surface ( 22 ) in contact with the stopper ( 10 ) and the variable volume chamber ( 18 ) is at its intended maximum volume there is a clearance of no more than 2 mm between the rod shoulder ( 34 ) and backstop shoulder ( 32 ). 
     
     
         9 . A syringe as claimed in  claim 1 , in which the variable volume chamber ( 18 ) has an inner diameter of between 4 mm and 5 mm. 
     
     
         10 . A syringe as claimed in  claim 1 , in which the syringe ( 1 ) is dimensioned so as to have a nominal maximum volume of between 0.4 ml and 0.6 ml. 
     
     
         11 . A syringe as claimed in  claim 1 , in which the syringe ( 1 ) is an ophthalmic syringe and the variable volume chamber ( 18 ) is filled with an injectable medicament comprising a medicament suitable for the treatment of an ocular disease and the outlet ( 12 ) is reversibly sealed. 
     
     
         12 . A syringe pack comprising a sealed package and a sterile syringe ( 1 ) as claimed in  claim 1 . 
     
     
         13 . A method of assembling a syringe, the method comprising the steps of:
 i) providing a body ( 2 ) and a stopper ( 10 ), the body ( 2 ) comprising an outlet ( 12 ) at an outlet end ( 14 ) and the stopper ( 10 ) being arranged within the body ( 2 ) such that a front surface ( 16 ) of the stopper ( 10 ) and the body ( 2 ) define a variable volume chamber ( 18 ) from which a fluid ( 20 ) can be expelled though the outlet ( 12 ), the stopper ( 10 ) providing a sealing function by defining the rear of the variable volume chamber ( 18 ) with a fluid tight seal, the outlet ( 12 ) being releasably sealed and the variable volume chamber ( 18 ) containing a medicament; and   ii) providing a plunger ( 4 ) comprising a plunger contact surface ( 22 ) at a first end and a rod ( 26 ) extending between the plunger contact surface ( 22 ) and a rear portion ( 25 ) and arranging the plunger contact surface ( 22 ) and at least part of the plunger ( 4 ) within the body ( 2 ) without coupling the plunger ( 4 ) to the stopper ( 10 ).   
     
     
         14 . A method as claimed in  claim 13 , in which the variable volume chamber ( 18 ) contains an injectable medicament comprising a medicament suitable for the treatment of an ocular disease. 
     
     
         15 . A method as claimed in  claim 13 , in which the rod comprises at least one rod shoulder directed away from the plunger contact surface and a backstop is provided, the backstop including a backstop shoulder directed towards the outlet end, the backstop is coupled to the syringe body after the plunger has been arranged in the body and the rod shoulder is arranged between the outlet end and the backstop shoulder. 
     
     
         16 . A method as claimed in  claim 13 , in which the plunger rod is dropped into the syringe body. 
     
     
         17 . A plunger suitable for use in the syringe of  claim 1 . 
     
     
         18 . A plunger suitable for the method of  claim 13 . 
     
     
         19 . A syringe as claimed in  claim 11  wherein the medicament comprises a VEGF antagonist. 
     
     
         20 . A syringe as claimed in  claim 19  wherein the VEGF antagonist comprises ranibizumab.