The present invention refers to a tubing set (12) suitable for use in co-operation with a medical liquid delivery device (10). The tubing set comprises: a delivery tube (68) suitable for supplying a medical liquid or blood to a patient； and a vial gate (24) for the connection of vials (26) containing drugs to be delivered into the medical liquid or blood. The vial gate comprises a delivery lumen (28), suitable for delivering the drug (30) from the vial to the delivery tube； and a vent lumen (32), suitable for providing a replacement fluid (34, 60) inside the vial in order to replace the delivered drug. The vial gate according to the invention further comprises at least one one-way valve (70, 72) placed along said vent lumen or said delivery lumen.
