A CARTRIDGE HOLDER (2), WHICH HAS A DISTAL END AND A PROXIMAL END, COMPRISES A COUPLING HOUSING PORTION (14) IN WHICH A CARTRIDGE CAN BE INSERTED AT LEAST PARTLY. THE COUPLING HOUSING PORTION (14) IS CONFIGURED TO BE COUPLED TO A PART OF A DRUG DELIVERY DEVICE. THE CARTRIDGE HOLDER (2) FURTHER COMPRISES A FIXING MEMBER (21) WHICH IS CONNECTED WITH THE COUPLING HOUSING PORTION (14). THE FIXING MEMBER (21) IS MOVEABLE RADIALLY INWARDLY TO A POSITION IN WHICH THE FIXING MEMBER (21) IS SUITABLE FOR SECURING THE CARTRIDGE AGAINST DISTAL DISPLACEMENT OF THE CARTRIDGE. (FIGURE 2)
