(EN) The invention relates to disposable devices for introducing substances into body cavities of a patient and the device comprises a container 1 for holding a substance which is connected to a tube-like member 2 ending in an opening 8 which is sealed by a frangible seal 3 located inside said opening 8 and is provided with an actuating rod 10 which ruptures and removes the seal 3 upon actuation. Said actuating rod 10 is provided with supporting rods 11', 11" extending to said container 1 and connected to said container 1 by frangible connections 12', 12", and consequently the supporting rods 11', 11" serve as a safe-guard against accidental rupture of said seal 3 and as a guide for a controlled movement of said actuating rod 10 and consequently secure the correct rupture of said frangible seal 3 and act as actuating handles for said actuating rod 10 when said supporting rods 11', 11" also define and protect an area to be kept sterile. The invention also relates to an injection moulding apparatus and to a method for making said device.