Figure 3.

Multi-target drugs. (A) The chemical structure of metamine, only multi-drug molecule used to treat Alzheimer’s disease patients; (B) Proposed mode of action of multi-target drugs through weak-linkage of networks. Drug repositioning; (C) Drug repositioning is the process of identifying new indication for known drug; (D) The approach of identifying new indication for known drug includes drug based, disease based or treatment based methods. The drug based approach consist of blinded or target based discovery of new indication while knowledge based discovery shared by drug based and disease based approach. Treatment based approach consist of target mechanism based discovery. Disease based and treatment based approach shares pathway based discovery [47].