INS and diabetes mellitus: According to recent research, the major considerations for oral insulin administration are: (i) keeping the stability and activity of insulin in GI tract; (ii) improving the adhesion ability of drug carrier to prolong the resistant time in the intestine, which can promote drug permeation; and (iii) adjusting drug releasing behavior according to the concentration changes of blood glucose, which can achieve intelligent glucose management, thus, decreasing the multiple side effects from diabetes [12–14].