Drug delivery device with a rotatable drive mechanism

Abstract

A rotatable drive mechanism for a drug delivery device may include a lead screw having a distal end, a proximal end, and external threads, a bearing, and a ball screw driver having a threaded aperture wherein the threaded aperture is configured to rotatably engage with the external threads of the lead screw. The mechanism may further include a biasing device disposed between the bearing and the ball screw driver generating an axial drive force, and an activation device configured to release the biasing device and allowing the biasing device to expand from a compressed position to an extended position through which the axial drive force of the biasing device causes the ball screw driver to axially move toward the distal end of the lead screw and rotate the lead screw such that a threaded engagement between the lead screw and the ball screw driver bears the axial drive force.

What is claimed: 
     
         1 . A drug delivery device comprising:
 a housing;   a drug container disposed within the housing and including a proximal end and a distal end; and   a drive mechanism activatable to expel a drug from the drug container, the drive mechanism comprising:
 a stopper movably disposed within the drug container; 
 a plunger configured to translate in a distal direction and rotate relative to the housing; 
 a biasing member operably coupled to the plunger; and 
 an annular member operably coupled to the plunger and rotationally fixed relative to the housing. 
   
     
     
         2 . The drug delivery device of  claim 1 , wherein the biasing member, via the drive mechanism, is configured to rotate the plunger. 
     
     
         3 . The drug delivery device of  claim 1 , wherein the annular member has a threaded interior surface. 
     
     
         4 . The drug delivery device of  claim 3 , wherein the drive mechanism comprises an elongate member having a threaded external surface threadingly engaged with the threaded interior surface of the annular member 
     
     
         5 . The drug delivery device of  claim 4 , wherein the elongate member directly coupled to the plunger to drive rotation thereof, such that the relative rotation of the elongate member and the plunger are the same. 
     
     
         6 . The drug delivery device of  claim 3 , wherein at least a portion of the plunger has a threaded exterior surface. 
     
     
         7 . The drug delivery device of  claim 6 , wherein the plunger comprises a telescoping plunger assembly. 
     
     
         8 . The drug delivery device of  claim 3 , wherein the biasing device comprises a coil spring. 
     
     
         9 . The drug delivery device of  claim 1 , wherein the drive mechanism converts rotational motion into linear motion of the plunger. 
     
     
         10 . The drug delivery device of  claim 1 , wherein the drive mechanism comprises an elongate member having a threaded external surface threadingly engaged with the threaded interior surface of the annular member; and further comprising a coupler configured to receive a first rotational velocity from the elongate member and deliver a second rotational velocity to the plunger. 
     
     
         11 . The drug delivery device of  claim 1 , further comprising an activation device operably coupled to the drive mechanism to control activation thereof. 
     
     
         12 . The drug delivery device of  claim 1 , further comprising a drug delivery member in fluid communication with the distal end of the drug container. 
     
     
         13 . The drug delivery device of  claim 1 , further comprising a drug in the drug container.