ABSTRACT
Drug discovery may be dened as the discovery, creation, or design of molecules that shows promise to cure diseases ailing humankind. The process of drug discovery is elaborative, utilizing time and resources, both human and nancial. It involves the identication of lead molecules followed by their synthesis, characterization, and screening for the desired therapeutic efcacy. Increasingly, scientists have been using the word target in drug designing and development, but the denition of the word target, their roles in disease pathways, drug development, and even their number remains controversial. Dening targets can solve, in a way, the puzzle of number of targets (druggable targets). The meaning of druggability is that researchers have the appropriate science and technology in hand to develop antagonists to a particular target. The druggable targets for the small-molecule drugs belong to protein families, which include G-protein-coupled receptors, ion channels, nuclear receptors, proteases, phosphodiesterases, kinases, and other key enzymes. The secreted proteins such as cell surface receptors are the druggable targets for the large-molecule drugs.
