Autoinjector

Abstract

An autoinjector includes a main body having a container, the container having a drug therein, a hollow needle coupled to the container through which the drug can be delivered. The autoinjector also has a power source having a liquefied gas therein as a driver, a flow regulator, and at least one outlet through which some of the driver can exit the power pack in a gaseous state. The power source and container are coupled together for operation such that, when an injection is initiated, the flow regulator will control an exit rate of the driver such that the liquefied gas in the power source is maintained at substantially its vapor pressure and the power source will adjustably apply a force to deliver the drug via the hollow needle at a delivery rate that is a constant delivery rate.

We claim: 
     
         1 . An autoinjector comprising:
 a main body that includes:
 a container having a drug therein; 
 a hollow needle coupled to the container; and 
 a power source coupled to the container, the power source including:
 a liquefied gas therein as a driver at a first pressure, and 
 a flow regulator configured to regulate a flow of the driver out of he power source at a second pressure less than the first pressure, 
 wherein the driver at the second pressure provides an adaptively variable force to drive the drug from the container and out the hollow needle. 
 
   
     
     
         2 . The autoinjector of  claim 1 , wherein the flow regulator includes a plurality of micro holes. 
     
     
         3 . The autoinjector of  claim 1 , wherein the flow regulator delivers a constant flow of the driver to the container. 
     
     
         4 . The autoinjector of  claim 1 , wherein the main body further comprises an intermediate member located between the power source and the container such that the adaptively variable force moves the intermediate member to drive the drug out of the container. 
     
     
         5 . The autoinjector of  claim 4 , wherein the intermediate member comprises at least one of: a close-ended tube, a sliding cup, a plunger rod, a telescoping column, a flexible ribbon, or a collapsible bellows. 
     
     
         6 . The autoinjector of  claim 1 , wherein the liquefied gas is housed within a canister, and the power source further includes a cavity for receiving a flow of the driver from the canister. 
     
     
         7 . The autoinjector of  claim 6 , wherein the cavity is upstream the flow regulator. 
     
     
         8 . The autoinjector of  claim 1 , wherein the liquefied gas is housed within a canister, and the power source further includes a valve mechanism for controlling a flow of the driver from the canister. 
     
     
         9 . The autoinjector of  claim 8 , wherein the valve mechanism includes a valve stem and a biasing member to bias the valve stem towards a closed position. 
     
     
         10 . The autoinjector of  claim 8 , wherein the valve mechanism is positioned upstream the flow regulator. 
     
     
         11 . The autoinjector of  claim 8 , wherein the valve mechanism is a pressure regulator. 
     
     
         12 . The autoinjector of  claim 8 , wherein the valve mechanism is configured to control a flow of the driver from the canister to provide an intermediate pressure that is at a constant pressure. 
     
     
         13 . The autoinjector of  claim 8 , wherein the valve mechanism is configured to reduce the pressure of the driver from the first pressure to an intermediate pressure, which is less than the first pressure and greater than the second pressure. 
     
     
         14 . The autoinjector of  claim 13 , wherein the power source further includes a cavity for receiving the driver at the intermediate pressure. 
     
     
         15 . The autoinjector of  claim 13 , wherein the first pressure is about 108 to 845 psi, the intermediate pressure is about 108 to 140 psi, and the second pressure is about 10 to 20 psi. 
     
     
         16 . The autoinjector of  claim 13 , wherein the first pressure is about 31 to 71 psi, the intermediate pressure is about 31 to 71 psi, and the second pressure is about 10 to 20 psi. 
     
     
         17 . The autoinjector of claim wherein the first pressure is about 108 to 845 psi and the second pressure is about 10 to 20 psi. 
     
     
         18 . The autoinjector of  claim 1 , wherein the first pressure is about 31 to 71 psi and the second pressure is about 10 to 20 psi. 
     
     
         19 . The autoinjector of  claim 1 , wherein the power source is mounted within the container. 
     
     
         20 . The autoinjector of  claim 19 , wherein the flow regulator is positioned completely within the container. 
     
     
         21 . The autoinjector of  claim 1 , wherein the power source is operatively coupled to the container or directly coupled to the container. 
     
     
         22 . The autoinjector of  claim 21 , wherein the power source is operatively coupled to the container, and wherein the main body further comprises an intermediate member located between the power source and the container such that the adaptively variable force moves the intermediate member to drive the drug out of the container.