VALVE STOPPER FOR A MEDICAL INJECTION DEVICE AND MEDICAL INJECTION DEVICE FOR INJECTING AT LEAST ONE COMPOSITION

摘要

The invention relates to a valve stopper (1) configured to be positioned inside a barrel (101) of an injection device (100) for injecting at least one composition through a distal end (104) of the barrel, said valve stopper (1) comprising: a membrane (2) comprising a proximal face (6) and a distal face (7), the membrane being configured to separate a first, distal chamber (108) of the barrel from a second, proximal chamber (109) of the barrel, a lateral wall (3) extending distally, or both distally and proximally, from the membrane (2) to define at least a distal cavity (4), the lateral wall (3) comprising a circumferential sealing surface (8) configured to sealingly engage the inner surface (102) of the barrel, characterized in that the proximal face (6) of the membrane (2) presents a concave shape and the membrane (2) comprises a notch (10, 20) extending through at least a part of the thickness of the membrane (2) between the proximal face (6) and the distal face (7), the notch (10, 20) being configured to selectively create a fluid path (30) through the membrane (2) from the proximal face (6) to the distal face (7) depending on the pressure exerted by a composition onto the proximal face (6) of the membrane (2) for transferring fluid only from the second chamber (109) to the first chamber (108).