Strategies for Coupling Molecular Units if Subsequent Decoupling Is Required

Chemists spend a great deal of time developing new methodologies to connect various molecules and add decorations to molecules of biological origin. There are many circumstances when there is a need to couple two or more units and then decouple them later. There is no doubt that decoupling chemistry is much less developed than coupling chemistry. However, there are many situations that call for the use of reliable disconnection reactions. The most common reason is to better control the delivery of the active drug. The concept of codrugs is similar. Codrug or mutual prodrug is an approach where various effective drugs, which are associated with some drawbacks, can be modified by attaching with other drugs of same or different categories directly or via a linkage. More appropriately one can say combining two different pharmacophores with similar or different pharmacological activities elicit synergistic action or help to target the parent drug to specific site/organ/cells respectively.