Abstract: An arrangement of drug delivery devices is provided with interchangeable members and non-interchangeable members.

Abstract: A cartridge assembly for a drug delivery device is described. The cartridge assembly includes (i) a cartridge containing a drug, the cartridge including a dispensing end; (ii) a cartridge holder, the cartridge holder defining an interior cartridge holding section, in which the cartridge is arranged within the cartridge holding section; and (iii) a fixing member. The fixing member includes a fixing surface, in particular a radially oriented surface, which is arranged to abut a cartridge surface of the cartridge, in particular a radially oriented surface. The cartridge surface is a proximal surface which faces away from the dispensing end of the cartridge, and the cartridge surface is arranged between the dispensing end of the cartridge and the end opposite of the dispensing end.

Abstract: A cartridge assembly for a drug delivery device can include: a cartridge holder, a cartridge containing a drug, and a fixing member, wherein the cartridge holder includes an interior cartridge holding section, the cartridge being arranged in the cartridge holding section, wherein the fixing member is axially secured to the cartridge holder and secures the cartridge permanently in the cartridge holder.

Abstract: A cartridge assembly for a drug delivery device is described. The cartridge assembly includes a cartridge containing a drug, the cartridge including a dispensing end; a cartridge holder, the cartridge holder defining an interior cartridge holding section, where the cartridge is arranged within the cartridge holding section; and a fixing feature. The fixing feature includes a fixing surface, in particular a radially oriented surface, which is arranged to abut a cartridge surface of the cartridge, in particular a radially oriented surface, to prevent removal of the cartridge from the cartridge holder such that the cartridge is permanently secured in the cartridge holder. The cartridge surface is a proximal surface which faces away from the dispensing end of the cartridge, wherein the cartridge surface is arranged between the dispensing end of the cartridge and the end opposite of the dispensing end, and wherein the fixing feature is integrated into the cartridge holder.