Tube management structures for an automatic compounder system are provided. A tube management structure may be implemented as a backpack attached to a pump cartridge of the compounder system. Flexible tubing may extend from an output port of the pump cartridge into an internal recess of the backpack. A connector may be provided on an end of the tubing that extends out of the backpack through an opening in the backpack. An additional opening may be provided in the backpack in which the connector may be stored when the cartridge is not in use by the system. The compounder system may include a sensor configured to view the connector through an opening in the cartridge when the connector is disposed in the additional opening. The tubing may be pulled from within the backpack so that the connector can be connected to a receiving container.
