A fluid pathway assembly includes a needle insertion mechanism, a fluid conduit, and a fluid pathway connection. The fluid pathway assembly may further include a drug container to hold a drug fluid prior to initiation of the injection. The assembly may include a carrier disposed along at least a portion of the fluid pathway assembly, and/or a drug container. The fill-finish cartridge functions to retain the components of the fluid pathway assembly in a sterile condition, while allowing for easy integration of the fluid pathway assembly and the drug container into a standard fill-finish process. Methods of constructing a cartridge, filling a drug container included in a cartridge, and incorporating the same into a drug delivery device are disclosed.