Patent ID: 7896836

Claim:
An apparatus for mixing a fluid and medicament within a medicament delivery device, comprising: a pressure member comprising a barrel, a movable stopper located therein and a telescopic plunger engaged to said movable stopper, said telescopic plunger having a biasing spring therein and said pressure member having a pressure member outlet, said pressure member having a first and a second position; a valve having an outlet and an inlet in fluid communication with said pressure member outlet; a stop member comprising releasable cooperating detents on said barrel and said telescopic plunger wherein said stop member retains said pressure member in said second position wherein said releaseable cooperating detents are adapted to withstand the resultant force generated by retention of said pressure member in said second position; a medicament dosing member having a chamber therein including a chamber inlet in fluid communication with said valve outlet and a chamber outlet, a medicament in said chamber and membranes sealing said chamber inlet and outlet; and a needle having a distal end and a proximal end wherein said proximal end is in fluid communication with said chamber outlet and said distal end is adapted for parenteral delivery; whereby transition of said pressure member from said first position to said second position generates fluid under pressure at said pressure member outlet and opening of said valve releases fluid under pressure into said chamber inlet, breaching said membranes and expressing said medicament in said chamber through said chamber outlet, and through said needle.