Pneumatic injector

Abstract

This document discloses, among other things, an air-powered auto-injector device for subcutaneous delivery of a rescue drug. The device is configured for self-administered treatment of anaphylactic shock. Air is compressed by relative movement of a piston and a cylinder and released to subcutaneously drive an hypodermic needle.

1 . An auto-injector comprising:
 a cylinder;   a piston configured to compress air in the cylinder;   a valve coupled to the cylinder and configured to control release of a pressure in the cylinder, and   a needle carrier configured to travel in a channel using the pressure in the cylinder.   
     
     
         2 . The auto-injector of  claim 1  wherein the valve includes a diaphragm. 
     
     
         3 . The auto-injector of  claim 2  wherein the valve includes a spike. 
     
     
         4 . The auto-injector of  claim 1  further including a needle guide affixed to a tip of the needle. 
     
     
         5 . The auto-injector of  claim 1  wherein the needle carrier includes a dosage reservoir. 
     
     
         6 - 18 . (canceled) 
     
     
         19 . The auto-injector of  claim 1  wherein the needle carrier is configured to couple to a hypodermic needle. 
     
     
         20 . The auto-injector of  claim 1  wherein the cylinder includes a shoulder and the piston includes a shoulder. 
     
     
         21 . The auto-injector of  claim 1  further including a housing having a first part and having a second part and wherein the piston is configured for movement relative to the cylinder corresponding to movement of the first part relative to the second part. 
     
     
         22 . The auto-injector of  claim 1  wherein the needle carrier is configured to move a needle from a retracted position to an ejected position. 
     
     
         23 . A device comprising:
 a housing having a first part and a second part, the first part configured for movement relative to the second part;   a plurality of cylinders and pistons configured for movement corresponding to movement of the first part relative to the second part, the plurality of cylinders and pistons configured to compress air;   a valve coupled to at least one cylinder and configured to control release of a pressure in the at least one cylinder; and   a hypodermic needle configured to travel in a channel using the pressure in the at least one cylinder.   
     
     
         24 . The device of  claim 23  wherein the channel is configured to carry the needle from a retracted position to an ejected position. 
     
     
         25 . The device of  claim 23  wherein the hypodermic needle is configured to deliver fluid based on pressure in the channel. 
     
     
         26 . The device of  claim 23  wherein the valve includes a diaphragm. 
     
     
         27 . The device of  claim 26  wherein the diaphragm is configured for rupture. 
     
     
         28 . The device of  claim 23  wherein the plurality of cylinders and pistons are configured in a flat arrangement. 
     
     
         29 . A method comprising:
 compressing air in a cylinder having a piston configured for relative movement based on movement of a first part of a housing relative to a second part of the housing;   opening a valve coupled to the cylinder at a predetermined position of the piston relative to the cylinder, wherein opening the valve includes releasing the pressure in the cylinder; and   moving a hypodermic needle in a channel based on the pressure in the cylinder.   
     
     
         30 . The method of  claim 29  wherein opening the valve includes rupturing a diaphragm. 
     
     
         31 . The method of  claim 30  wherein rupturing the diaphragm includes contacting the diaphragm with a spike. 
     
     
         32 . The method of  claim 29  wherein moving the hypodermic needle includes using a guide affixed to a tip of the needle. 
     
     
         33 . The method of  claim 29  further including ejecting a fluid from the needle based on the pressure. 
     
     
         34 . The method of  claim 29  wherein compressing air in the cylinder includes moving a sleeve in a cylinder.