Escape from Flatland 2: complexity and promiscuity

Toxicity plays a major role in attrition in the clinic and promiscuity has been linked to toxicity. A number of molecular descriptors have been identified that contribute to promiscuity including ionization and logP. In this study we report on the relationship between complexity, as measured by two descriptors [fraction sp(3) (Fsp(3)) where Fsp(3) (number of sp(3) hybridized carbons/total carbon count) and chiral carbon count], and promiscuity as well as Cyp450 inhibition. We find that increasing complexity reduces promiscuity and Cyp450 inhibition. As an understanding of key property descriptors has helped the pharmaceutical industry to address some of the deficiencies of compounds as pertains to bioavailability, awareness of the descriptors that impact promiscuity should allow us to better address toxicity in the clinic.