A drug supply system for CED (convection-enhanced delivery) catheter infusions is provided, the system including a drug conducting system having a drug depot and a catheter supply line and a conveying device that provides for conveying the drug from the drug depot into the catheter supply line. The drug conducting system is a system that is closed to the outside in a fluidic seal The drug supply system further includes a conveying fluid conveying system arranged between the conveying device and the drug supply system and is connected to the conveying device and to the drug depot, via a drug displacement element, without fluid-drug contact.