Abstract

Drug discovery efforts in the pharmaceutical industry prior to the 1980’s relied on the use of whole animals or organ explants. Typically, compounds or classes of compounds synthesized by chemists specifically for Pharmacy applications or for another industry such as the dye industry were tested in an array of assays that relied on phenotypic changes (morphological, physiological, electrophysiological, etc.) observed in animals or organ explants or tissue extracts [1]. This approach has led to a set of powerful drugs that are in use even today [2]. These leading discoveries have also served as the starting points for other drugs in the class based on chemical modifications of the original discoveries. Thus, in this era, drugs were discovered entirely using Phenotypic Drug Discovery (PDD) approaches.

Abbreviations: PDD: Phenotypic Drug Discovery; HTS: High Throughput Screening; GPCRs: G-protein coupled receptors; TDD: Target based Drug Discovery; NCATS : National Center for Advancing Translational Sciences; NIH: National Institutes of Health; DARPA: Defense Advanced Research Project Agency ; FDA: Food and Drug Administration; iPSCs: Induced Pluripotent cells