The more and more drugs in basic research, drug discovery, and drug development have been diverting to various types of structural perspectives, in which conjugated constructions emerge with remarkable functions superior to conventional drugs. These conjugated drugs include small molecules and macro compounds. The main difference between conjugated and conventional structural modifications is multi-functionalities. These multi-functionalities combine one or more bioavailable moieties: a drug segment, a ligand segment, and a linker segment. The drug segment plays the critical therapeutic role, the ligand segment is in charge of the selectivity, and the linker segment connects the drug and the ligand together. The simplest conjugate would be bi-functionalized molecule that biologic properties has been changed upon intent design. This review will summarize the most recent advancements in the medicinal conjugations under development and at various other stages of development as they are investigated as for novel drugs, drug candidates, and drug leads.
