A cartridge interface assembly (80) characterised by a driving plunger (82) including an outer shaft (84), and a driver (86) including an inner shaft (88) movable telescopically with respect to the outer shaft (84), wherein rotation of the driver (86) causes the driving plunger (82) to advance in a direction away from the driver (86), and wherein the cartridge interface assembly (80) is inserted in a cartridge (22) in which a plunger (24) is slidingly disposed, and rotation of the driver (86) causes the driving plunger (82) to advance distally in the cartridge (22) until abutting against the plunger (24).
