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).
