A system, components and methods for mixing the contents of a first container and a second container. The system and components include the first container having a stopper sealing the opening to the container. The second container includes a port assembly including a port housing connected to the second container and a retainer constructed to connect to the first container. The retainer is configured to rotate and move axially relative to the port housing. The port assembly further includes an axially fixed actuator constructed to force the stopper into the first container when the retainer is rotated relative to the port housing. Rotation of the retainer relative to the port assembly also opens a plug securing an opening in the second container. The system may include a hanger for hanging the system only when fluid communication is established between the first and second containers. Methods of preventing errors in medication delivery are also described.
