Abstract: Fluid delivery devices for delivering therapeutic agents are described. More particularly, this disclosure relates to drug reconstitution devices having a plurality of components movable with respect to one another such that an active agent and a solvent can be reconstituted within the device prior to injection. The fluid delivery devices can include a housing, a cartridge holder, a cartridge disposed within the cartridge holder, a button rod, and a foot. The cartridge stores the active agent and the solvent, which are separated by one or more stoppers. The button rod and foot can provide an axial force upon the stopper(s) in the cartridge to inject the fluid once reconstituted. The foot and the button rod can be separate components, thereby enabling the foot to rotate independently with respect to the button rod as the cartridge holder is rotated to reconstitute the therapeutic and prime the device for injection.