Methods and Systems for Dosing a Medicament

Abstract

A manually actuated pump, such as a bolus delivery circuit of an insulin pump, combines a direct drive piston system with a lost motion valve system, to deliver reliably a full bolus dose, while precluding partial dosing or inadvertent overdosing conditions. The pump may also include a signaling device to indicate when a full bolus dose is delivered.

What is claimed is: 
     
         1 . A method of dosing a medicament using a mechanical pump system comprising an actuation element, a direct drive piston system including a piston, and a lost motion valve system, the method comprising the steps of:
 moving the actuation element from a rest position to a fill end position to fill incrementally a piston chamber of the piston system with medicament from a reservoir;   moving the actuation element an additional distance to a point of no return to move a valve of the valve system from a fill position to a dosing position; and   moving the actuation element past the point of no return to force a full dose of medicament out of the piston chamber to a dosing conduit.   
     
     
         2 . The method of  claim 1 , wherein moving the actuation element from the rest position to the fill end position retracts the piston relative to the piston chamber. 
     
     
         3 . The method of  claim 1 , wherein the direct drive piston system comprises at least one of a rack and gear system and a cam and follower system. 
     
     
         4 . The method of  claim 3 , wherein the direct drive piston system comprises both the rack and gear system and the cam and follower system. 
     
     
         5 . The method of  claim 1 , wherein moving the actuation element from the rest position to the fill end position does not move the valve. 
     
     
         6 . The method of  claim 1 , wherein when the actuation element is moved past the point of no return, the piston is decoupled from the actuation element and automatically delivers a full dose of medicament to the dosing conduit. 
     
     
         7 . The method of  claim 1  further comprising the step of returning the actuation element to the rest position after dosing to reset the mechanical pump system. 
     
     
         8 . The method of  claim 7 , wherein the actuation element is returned to the rest position automatically. 
     
     
         9 . The method of  claim 7 , wherein the actuation element passes through a reengagement position prior to reaching the rest position. 
     
     
         10 . The method of  claim 9 , wherein cycling of the actuation element from past the point of no return to a position intermediate with the reengagement position delivers no additional medicament. 
     
     
         11 . The method of  claim 7 , wherein the valve is moved from the dosing position to the fill position by the actuation element. 
     
     
         12 . The method of  claim 1 , wherein the valve allows fluidic communication between the reservoir and the piston chamber only when the valve is in the fill position. 
     
     
         13 . The method of  claim 1 , wherein the valve allows fluidic communication between the piston chamber and the dosing conduit only when the valve is in the dosing position. 
     
     
         14 . The method of  claim 1 , wherein the piston system and the valve system are configured to preclude direct fluidic communication from the reservoir to the dosing conduit. 
     
     
         15 . The method of  claim 14 , wherein the valve system includes a redundant sealing system comprising two sealing elements disposed between the reservoir and the dosing conduit. 
     
     
         16 . The method of  claim 15 , wherein the valve system further comprises a venting port disposed between the two sealing elements for dumping medicament leaked between the two sealing elements. 
     
     
         17 . The method of  claim 1 , wherein the reservoir is configured to hold a first volume of medicament less than a volume of a replenishment reservoir. 
     
     
         18 . The method of  claim 1 , wherein the piston system and the valve system are configured to preclude delivery of a partial dose of medicament to the dosing conduit. 
     
     
         19 . The method of  claim 18 , wherein the mechanical pump system further comprises an interlock for retaining the valve in the dosing position until a full dose of medicament is delivered. 
     
     
         20 . The method of  claim 1 , wherein cycling the actuation element between the rest position and a position before the point of no return delivers no medicament. 
     
     
         21 . The method of  claim 1 , wherein the actuation element exerts a first increasing reaction force against an actuating force when filling the piston chamber to the fill end position and a second lower reaction force when the actuation element moves past the fill end position. 
     
     
         22 . The method of  claim 1  further comprising the step of delivering a signal only when the full dose is delivered to the dosing circuit. 
     
     
         23 . The method of  claim 22 , wherein the signal is triggered by at least one of a mechanical, an optical, a capacitive, a potentiometric, and a magnetic input. 
     
     
         24 . The method of  claim 23 , wherein the signal is triggered based on detecting at least one of a specific position, a change in position, a threshold velocity, and a change in velocity of a moving component of the mechanical pump system. 
     
     
         25 . The method of  claim 23 , wherein the signal comprises at least one of a tactile stimulus, an audible stimulus, a visual stimulus, an electronically detectable signal adapted to be received by an electronic device, and combinations thereof. 
     
     
         26 .- 52 . (canceled)