Automatic liquid drug preparation apparatus for preparing a liquid drug assemblage with a predetermined dosage of liquid drug. The liquid drug assemblage is prepared from a preparatory assemblage including a fluid control device having a body member with a syringe port, a vial adapter, and an administration port, a vial pre-filled with powder or liquid medicament, and a syringe pre-filled with diluent for mixing with the medicament. The automatic liquid drug preparation apparatus includes a housing, a cradle for receiving the preparatory assemblage, and a controller for controlling a motorized syringe drive unit for selectively transferring liquid contents between the syringe and the vial, a motorized cradle drive unit for selectively rotating the cradle relative to the housing, and a motorized vial adapter release unit for selectively detaching the vial adapter with its attached spent vial from the body member to form the liquid drug assemblage.