Training cartridge for a drug delivery device

#The present application is a U.S. National Phase application pursuant to 35 U.S.C. §371 of International Application No. PCT/EP2011/058925 filed May 31, 2011, which claims priority to European Patent Application No. 10164701.4 filed Jun. 2, 2010. The entire disclosure contents of these applications are herewith incorporated by reference into the present application.

#The present invention relates to a cartridge for a drug delivery device and in particular to a training or test cartridge that allows a user to get trained and to become accustomed to the handling of a drug delivery device without the necessity of administering a dose of a medicinal product or placebo, e.g. by injection.

#Drug delivery devices allowing for multiple dosing of a required dosage of a liquid medicinal product, such as liquid drugs, and further providing administration of the liquid to a patient, are as such well-known in the art. Generally, such devices have substantially the same purpose as that of an ordinary syringe.

#Without limitation, the present invention will be explained in greater detail below in connection with preferred embodiments and with reference to the drawings in which:

#FIG. 1 schematically illustrates a first embodiment of a training cartridge comprising a detachable closure means,

#FIG. 2 shows the cartridge with disassembled closure means,

#The cartridge 10 as illustrated in FIGS. 1 through 8 comprises an elongated hollow body 12 of substantially cylindrical shape, a piston 18 slidably disposed in the body 12 along the body's long axis specifying an axial direction. The cartridge 10 further comprises a closure means 14 adapted to seal one axial end portion of the body 12. The body 12 and the closure means 14 constitute a cartridge housing of substantially cupped geometry. The piston 18 typically comprising a circular cross-section is frictionally engaged with the inner surface of the body 12. The interior volume 16 confined by the body 12, the closure means 14 and the piston 18 is coupled to the exterior via at least one fluid escape channel 28 extending in an interface section of body 12 and closure means 14.

#The closure means 14 comprises an axially inwardly directed end wall 30 that abuts with an axial end of the body's 12 cylindrical wall. In the embodiment according to FIGS. 1 to 8, the body 12 comprises a stepped down rim portion 34 at both of its axial end sections. In an assembly configuration, as illustrated in FIG. 1, the rim 34 radially overlaps with the sidewall of a corresponding receptacle 36 of the closure means 14. In order to provide at least one fluid escape channel 28 in the intersection of closure means 14 and body 12, respective contact surfaces of rim 34, receptacle 36 and their corresponding socket 35 and/or substantially radially extending end face 37 comprise at least one groove, that serves as fluid escape channel and which allows for an escapement of a fluid or a gaseous medium when the piston 18 is subject to a distally directed axial movement, that is, a movement towards the closure means 14.

#For the formation of at least one fluid escape channel, it may already be sufficient to provide a radially extending groove at the axial end face of the rim 34 of the body 12 and wherein this radial groove extends into an axially extending groove at the circumference of the rim 34 and is finally coupled to another radially extending groove in the socket portion 35 of the body 12.