The present invention relates to an arrangement for use in a drug delivery device comprising a cartridge holder, the cartridge holder comprising an opening at its distal end, a needle holder and one or more intermediate elements, wherein when the needle holder is mounted to the cartridge holder and the one or more intermediate elements are arranged in the opening of the cartridge holder whereby the size of the free space within the opening is reduced. Furthermore, it relates to a drug delivery device which is comprising such an arrangement and to a method for stabilizing a septum located at the distal end of a medicament cartridge.