| abstract |
A cartridge system for use with a drug delivery device (100 '), comprising: - a pre-filled cartridge comprising: a) a cartridge body (210) containing a drug, b) a piston (250) ) slidably disposed in the cartridge body (210) and adapted to provide a proximal seal, the piston (250) comprising: b1) a first piston member (260) comprising a first material and forming a distal end , a proximal end and a sealing periphery in contact with the cartridge body (210), the distal end being in contact with the medicament and the proximal end of the first piston member (260) comprising a facing aperture of proximally, and b2) a second piston member (270) comprising a lower compressibility material with respect to the first material, the second piston member (270) comprising a man-shaped portion. chon disposed in the proximally facing aperture of the first piston member (260), the second piston member (270) comprising a proximally facing aperture forming a socket; and - a plug unit (280) couplable or coupled in the socket of the second piston member (270), the plug unit (280) comprising an electronic sensor unit (290) configured to determine the axial position of the piston ( 250) within the cartridge body (210) and the plug unit (280) being at least partially received within the proximally oriented opening of the first piston member (260). |