Needle-free Transdermal Injection Device

Abstract

An apparatus for use in injectate delivery includes an actuator including a linkage, a force generating mechanism mechanically coupled to the linkage, and a controller coupled to the force generating mechanism. The force generating mechanism includes a passive force generator and an active force generator. In operation and on the basis of a control signal, the controller is configured to control the force generating mechanism to provide an input force to the linkage that is a combination of the first force provided by the passive force generator and a second force provided by the active force generator.

What is claimed is: 
     
         1 . An apparatus comprising:
 a needle free injector including:
 a housing, 
 a chamber in the housing for holding an injectate, 
 a nozzle to discharge the injectate, the nozzle formed by an opening in the chamber, 
 a plunger slidably disposed within the chamber, and 
 a spring coupled between the plunger and the housing, the spring being configured to apply a spring force to the plunger to discharge the injectate from the chamber through the nozzle; 
   a motor that is configured to re-set the spring after the spring has applied the spring force to the plunger; and   a controller configured by computer executable code to execute a reset mode including applying a resetting force to compress the spring such that mechanical energy is stored in the spring for use in discharging the injectate.   
     
     
         2 . The apparatus of  claim 1 , wherein the motor is configured to generate a torque after having engaged the spring, the torque generating a corresponding force that resets the spring. 
     
     
         3 . The apparatus of  claim 1 , further comprising a base station that receives the needle-free injector and wherein the motor is in the base station. 
     
     
         4 . The apparatus of  claim 3 , wherein the base station automatically resets the spring once the motor of the base station is engaged with the spring. 
     
     
         5 . The apparatus of  claim 3 , wherein the base station includes an actuator that is used to initiate resetting of the spring by the base station. 
     
     
         6 . The apparatus of  claim 3 , wherein the base station comprises manual resetting mechanism to enable an operator to manually reset the spring. 
     
     
         7 . The apparatus of  claim 1 , wherein the controller is further configured by computer executable code to execute an injection mode wherein the spring applies a net force to drive the plunger at a target velocity. 
     
     
         8 . The apparatus of  claim 7 , wherein the controller is further configured to modulate the spring force with the rotary motor to control the net force according to a target velocity profile. 
     
     
         9 . The apparatus of  claim 7 , wherein the spring is a helical spring that is configured to apply a linear force to the plunger, wherein the linear force is between two hundred newtons and three hundred newtons. 
     
     
         10 . The apparatus of  claim 1 , wherein the motor is an electric motor. 
     
     
         11 . The apparatus of  claim 1 , wherein the actively controlled force generating device includes a rotary motor. 
     
     
         12 . The apparatus of  claim 1 , wherein the spring is a helical spring. 
     
     
         13 . The apparatus of  claim 1 , wherein the spring is a torsion spring. 
     
     
         14 . The apparatus of  claim 1 , wherein the spring is a beam spring. 
     
     
         15 . The apparatus of  claim 1 , wherein the controller is disposed in the housing. 
     
     
         16 . A method comprising using a needle-free injector that comprises a housing, a chamber in the housing for holding an injectate, a nozzle to discharge the injectate, the nozzle formed by an opening in the chamber, a plunger slidably disposed within the chamber, and a spring coupled between the plunger and the housing, the method comprising causing the spring to apply a spring force to the plunger to discharge the injectate from the chamber through the nozzle and causing a motor to re-set the spring the spring after the spring has applied the spring force to the plunger. 
     
     
         17 . The method of  claim 16 , wherein causing a motor to re-set the spring the spring after the spring has applied the spring force to the plunger further comprises causing a base station that comprises the motor to receive the needle-free injector. 
     
     
         18 . The method of  claim 17 , wherein causing the motor to re-set the spring further comprises, after the base station has received the needle-free injector further comprises manually actuating a resetting mechanism. 
     
     
         19 . The method of  claim 17 , wherein causing the base station to receive the needle-free injector comprises causing the spring to engage the motor, thereby triggering an automatic reset of the spring.