Single actuated precision dose intermediate pumping chamber

A wearable drug delivery device, comprising:

• a reservoir configured to store a liquid drug;
• and
• a delivery pump device coupled to the reservoir for receiving the liquid drug from the reservoir, the delivery pump device comprising:
• a chamber body defining a pump chamber,
• an inlet port configured to enable a liquid drug from the reservoir to be drawn into the pump chamber,
• a sliding fluidic member including a flow orifice and a fluid pathway to a needle,
• a plunger including a plunger channel configured to be engaged with the sliding fluidic member, and
• a shape memory alloy wire coupled to the sliding fluidic member,
• wherein:
• the shape memory alloy wire is operable to draw the liquid drug from the reservoir through the inlet port and into the pump chamber by pulling the sliding fluidic member and the plunger in a first direction, and
• the sliding fluidic member is configured to enable the liquid drug to be drawn into the pump chamber and expelled from the pump chamber into a fluid pathway to a needle for output.