The present invention relates to a medical device comprising a base member (2), a container (20) comprising a container interior (28) adapted to accommodate a substance, and a container closure (23) for fluidly sealing the container interior, and fluid connection means (50) for establishing fluid connection to the container interior. A cover (4) removably mountable on a cover receiving portion (36) is operatively coupled with the fluid connection means (50) to cause a relative motion between the fluid connection means (50) and the container closure (23) in response to a relative motion between the cover (4) and the base member (2). The medical device further comprises a cover engagement mechanism (9, 37, 46, 49) configured to prevent movement of the cover in a dismounting direction relative to the cover receiving portion when the cover and the base member are in a first relative position in which the fluid connection means (50) and the container interior (28) are fluidly separated and to allow movement of the cover (4) in a dismounting direction relative to the cover receiving portion (36) when the cover and the base member are in a second relative position in which the fluid connection means and the container interior are fluidly connected.La présente invention concerne un dispositif médical comprenant un élément de base (2), un contenant (20) comprenant un intérieur de contenant (28) conçu pour recevoir une substance, et une fermeture de contenant (23) pour sceller de manière étanche et fluidique lintérieur de contenant, et un moyen de liaison fluidique (50) pour établir une liaison fluidique avec lintérieur de contenant. Un couvercle (4) pouvant être monté de manière amovible sur une partie de réception de couvercle (36) est couplé de manière fonctionnelle au moyen de liaison fluidique (50) pour entraîner un déplacement relatif entre le moyen de liaison fluidique (50) et la fermeture de contenant (23) en réponse à un déplacement relatif entre le couvercle (4) et
