A syringe adapter element (200) for use in a drug mixing system comprising: a housing element (500) having a syringe port (15) adapted for fluid connection with a syringe (40) and a fluid port (202) adapted for fluid connection with a fluid flow adapter element (204)； a needle (550) and at least one separation partition (502) disposed in said housing element (500), said needle (550) having a sealed orientation in which said at least one separation partition (502) blocks the flow of fluid through said needle (550) and a fluid flow orientation in which said needle (550) perforates said at least one separation partition (502) to allow fluid to flow through said needle (550) ； and an anti-separation device (206) adjacent to said fluid port (202), such that when said syringe adapter element (200) is connected to a fluid flow adapter element (204), said anti-fluid device separation (206) apply a force that acts against the separation of said syringe adapter element (200) from the fluid flow adapter element (204)； characterized in that said anti-separation device (206) comprises a ring member (208) with a plurality of elastic levers (210) disposed within a ratchet element (212), said ratchet element (212) having a first perforation (214) sized to prevent outward expansion of said elastic levers (210) and a second perforation (216), larger than the first perforation (214), sized to allow expansion of said elastic levers (210) outward , said elastic levers (210) being adapted to elastically hold a fluid flow adapter element (204), said anti-separation device (206) having first and second positions, in which the first position, said elastic levers (210) they are located in said first perforation (214) and are adapted to hold the fluid flow adapter element (204), and in the second position, said elastic levers (210) are they place in said second perforation (216) and are adapted to expand outwardly in order to release the fluid flow adapter element (204).Un elemento adaptador
