Devices for reconstituting and delivering lyophilized drugs

A drug-delivery device assembly comprising:

• a housing having an interior surface, a proximal end, and a distal end;
• a flexible drug reservoir disposed on the interior surface of the housing, the drug reservoir having a proximal reservoir compartment storing a liquid diluent and a distal reservoir compartment storing a lyophilized drug powder, wherein the proximal reservoir compartment is separated from the distal reservoir compartment by a frangible seal;
• a releasable mechanism positioned in the housing, the releasable mechanism comprising a rigid pivoting member configured to rotate about a central spindle, the rigid pivoting member comprising at least a first arm and a second arm configured to remain fixed relative to the first arm during rotation of the pivoting member;
• a compression member having a proximal end and a distal end and being disposed proximate the drug reservoir, the proximal end of the compression member being attached to a hinge, and the distal end of the compression member being secured by the first arm of the pivoting member;
• a biasing member configured to apply pressure to the compression member to bias the distal end of the compression member against the first arm of the pivoting member and toward the interior surface of the housing, wherein the distal end of the compression member is prevented from moving toward the interior surface by direct contact with a plane of the first arm of the pivoting member;
• an injection needle that is movable between a storage position and an injection position;
• an injection spring that applies a biasing force on the needle towards the injection position, wherein the injection needle is prevented from moving towards the injection position by engagement with the second arm of the pivoting member;
• wherein in response to actuation of the drug-delivery device assembly, the releasable mechanism is configured to rotate the pivoting member until:
• (i) the plane of the first arm of the pivoting member no longer directly contacts the compression member so that the compression member, acting under the pressure from the biasing member, rotates about the hinge to move the distal end of the compression member towards the interior surface of the housing, such that the compression member:
• compresses the proximal reservoir compartment against the interior surface to force the liquid diluent through the frangible seal and into the distal reservoir compartment, wherein the liquid diluent mixes with the lyophilized drug powder to form a drug mixture, and
• compresses the distal reservoir compartment against the interior surface to expel the drug mixture from the distal reservoir compartment;
• and
• (ii) the second arm of the pivoting member no longer engages the injection needle so that the injection needle, acting under the biasing force from the injection spring, moves to the injection position.