A disposable cartridge for a drug delivery device includes a flexible bag to accommodate a liquid medicament and having an opening adjacent to a sidewall, a socket having a fluid channel in fluid communication with a cartridge fluid coupling, and a housing covering at least a portion of the flexible bag and having a receptacle to receive the socket with the flexible bag. The socket extends into the opening of the flexible bag. The flexible bag's sidewall is fixed between the socket and the receptacle.