An assembly for closing the discharge nozzle of a syringe which is pre-filled with a drug or medication. A syringe in combination with a connecting structure removably maintain and support the closure in an operative orientation, which facilitates the rotational attachment of the syringe and the closure when the closure is in mating engagement with the connecting structure. A subsequent removal of the syringe and connected closure from the container or other type of connecting structure is thereby facilitated. The need for an individual to directly handle or touch the closure during its attachment to the syringe is restricted or eliminated. The closure assembly preferably also includes a tamper evident structure which reduces the chances of tampering with the syringe in order to access its contents.