Billions upon billions...of drugs

A new exploration of chemical space by Jean-Louis Reymond and Mahendra Awale suggests that drug researchers going as boldly as they might have barely even scratched the tip of the iceberg, to mix a metaphor, when it comes to synthesizing drug candidates. Writing in the journal ACS Chemical Neuroscience, the team suggests that the actual number of “small molecules” that might have physiological activity could number in the million billion billion billion billion billion billions (more than the number of stars in the universe, by one estimate). The Chemical Abstracts Service database lists a mere 67 million substances, less than a tenth of a percent of the chemical space suggested by the University of Berne team.