Injector

Abstract

An injector for delivering medicament comprises a collapsible container ( 1002 ) for containing the liquid medicament, a normally-closed valve ( 1004 ) coupled to the collapsible container ( 1002 ) for retaining the liquid medicament within the collapsible container and an injection means ( 1006 ) for delivering the liquid medicament from the collapsible container. The liquid medicament is maintained under pressure by a pressurising means ( 1003 ) which pressurises the liquid medicament such that it is delivered by the injection means ( 1006 ) when the normally-closed valve ( 1004 ) is opened.

1 . An injector for delivering a liquid medicament comprising, a collapsible container for containing the liquid medicament, a normally-closed valve coupled to the collapsible container for retaining the liquid medicament within the collapsible container, an injection means coupled to the normally-closed valve for delivering the liquid medicament from the collapsible container, and pressurising means for pressurising the liquid medicament contained within the collapsible container such that the liquid medicament is delivered by the injection means when the normally-closed valve is opened. 
     
     
         2 . An injector according to  claim 1  in which the injection means is a hollow needle such as a hypodermic needle, or in which the injection means is a needleless injection element for injecting medicament into a human or animal body. 
     
     
         3 . An injector according to  claim 1  in which the collapsible container and the pressurising means are housed within a rigid container, preferably in which the normally-closed valve is connected to the rigid container. 
     
     
         4 . An injector according to  claim 3  in which at least a portion of the rigid container is transparent, preferably in which the rigid container is formed from a transparent polymer or glass. 
     
     
         5 . An injector according to  claim 3  in which the rigid container includes a vent to allow displaced air within the rigid container to escape when the collapsible container is filled, preferable in which the vent is a closable vent. 
     
     
         6 . An injector according to  claim 3  in which the rigid container is hermetically sealed. 
     
     
         7 . An injector according to  claim 6  in which the rigid container has an inert gas atmosphere surrounding the collapsible container, preferably in which the inert gas is a gas having a low solubility in the liquid medicament, for example nitrogen. 
     
     
         8 . An injector according to  claim 3  in which the collapsible container is defined by internal walls of the rigid container and a piston that is slidably arranged within the rigid container, the volume of the collapsible container varying depending on the position of the piston. 
     
     
         9 . An injector according to any of  claim 1  in which the collapsible container is a bellows coupled to the normally-closed valve. 
     
     
         10 . An injector according to  claim 9  in which the bellows is formed from a transparent material. 
     
     
         11 . An injector according to  claim 1  in which the pressurising means is a biasing element that exerts a force that acts on the collapsible container. 
     
     
         12 . An injector according to  claim 11  in which the force acting to collapse the collapsible container is generated by a spring, for example a compressed helical spring arranged to urge the collapsible container to collapse. 
     
     
         13 . An injector according to  claim 12  in which the pressurising means comprises a spring and is an integral part of the collapsible container. 
     
     
         14 . An injector according to  claim 11  in which the force that acts on the collapsible container is generated by a compressed gas or a liquefied gas. 
     
     
         15 . An injector according to any of  claim 11  in which the pressurising means comprises a piston or ram that is urged by the force into contact with the collapsible container. 
     
     
         16 . An injector according to  claim 1  in which the normally-closed valve is a continuous flow valve or an aerosol valve. 
     
     
         17 . An injector according to  claim 1  in which the normally-closed valve comprises a spring that acts to urge the valve to a closed position, in which the spring is a non-metallic spring, for example a plastic spring. 
     
     
         18 . An injector according to  claim 1  comprising a manually operated switch for opening the normally-closed valve. 
     
     
         19 . An injector according to  claim 1  comprising an actuator for opening the normally-closed valve, in which the normally-closed valve is opened when the actuator is pressed against a patients skin. 
     
     
         20 . An injector according to  claim 1  in which the injection means is a needle and the normally-closed valve is arranged to open when the needle has been inserted a predetermined distance into the patient, the predetermined distance depending on the type of drug that is being delivered and the tissue that the delivery is required to be made into.