Quantification of the interrelationships of receptor pharmacologies within a tricyclic privileged structural scaffold through application of modified forward selection

Many neuropsychiatric drugs interact with more than one molecular target, and therapeutic indices might be improved by prospectively designing compounds with profiles optimized against a combination of targets. The dibenzo-epine scaffold is considered a privileged structure, and this scaffold has been explored rigorously in the search for potential novel neuropharmacologic treatments. Members of this chemical class are known to interact with many receptors and transporters, particularly those of the biogenic amine class. In this study, four points of diversity within a dibenzo-epine scaffold were varied systematically and the pharmacologic profiles of the compounds were assessed across 14 receptors and transporters thought to be important to clinical profiles of efficacy and safety. The resulting data were analyzed using a modified forward selection linear regression procedure, thus revealing potential pharmacophoric relationships of the assessed targets within this chemical class. The results highlight a strong covariance across numerous targets. Moreover, the outcome quantifies the innately problematic issue of prospectively designing compounds with defined affinities across multiple targets. Finally, an exploration of the correspondence of binding affinities to in vitro functional activity reveals an additional layer of complexity central to prospectively designing compounds to engage multiple targets. The apparent relatedness of the 5-HT(2a) and D₂ activities suggests that the structural pharmacophores of these receptors overlap more closely with each other than with members of their respective families.