Drug delivery devices and related methods of assembly are disclosed. The drug delivery device may include a housing and a container disposed therein. The container may include a reservoir containing a drug and a movable stopper. A first seal member may be connected to the container at a distal end of the reservoir. A first removable membrane may cover an exterior surface of the first seal member to maintain sterility of that surface prior to operation of the device. A fluid pathway assembly may be configured to establish fluid communication with the reservoir during operation of the device. A second seal member may be connected to a first end of the fluid pathway assembly. A second removable membrane may cover an exterior surface of the second seal member to maintain sterility of that surface prior to operation of the device.