A locking mechanism (200, 400, 500, 600, 700, 800) is provided for use with a reservoir (120, 320, 330) and a reservoir holder (104, 820) so as to prevent unwanted tampering with the reservoir (120, 320, 330). The mechanism (200, 400, 500, 600, 700, 800) comprises a main body (202) with an aperture (204, 430, 530) that is coupled to the reservoir (120, 320, 330). A hinged flange (214, 414, 514, 522, 622, 722) is provided on the main body (202). The flange (214, 414, 514, 522, 622, 722) folds inwards at the pivot point provided by the hinge (215), toward the aperture (204, 430, 530) of the main body (202), allowing the mechanism (200, 400, 500, 600, 700, 800) to pass over the ferrule (324) of the reservoir (120, 320, 330). Once the mechanism (200, 400, 500, 600, 700, 800) is placed over the cartridge (120, 320, 330), the flange (214, 414, 514, 522, 622, 722) folds toward the reservoir (120, 320, 330) at the pivot point, flexing away from the main body (202). The flange (214, 414, 514, 522, 622, 722) rests against the underside (325) of the reservoir ferrule (324), thereby retaining the reservoir (120, 320, 330) within the locking mechanism (200, 400, 500, 600, 700, 800). The locking mechanism (200, 400, 500, 600, 700, 800) may be for use with either a disposable or a reusable delivery device (100).
