From another point of view, colon drug delivery systems (CDDS) have been developed for their use in two main applications: (i) to deliver macromolecular drugs, such as protein or peptides that found in the colon a better environment to be absorbed without losing activity because of the relatively low proteolytic enzyme activity and good absorption (e.g., insulin, calcitonin, and vasopressin); and (ii) to increase the efficacy in prevention and treatment of colon related diseases (e.g., irritable bowel syndrome, inflammatory bowel diseases (IBD), and colorectal cancer) [15,16]. Here, CALCA is linked to irritable bowel syndrome.