Stereoselectivity in biologically active compounds

Toward a biological target, the potency of two enantiomers can sometimes differ considerably, sometimes be very similar (Table 26.1). Often the activity is concentrated in only one enantiomer. When such a high stereoselectivity arises, it is admitted that the mechanism of action at the molecular level involves a highly specific interaction between the ligand, a chiral molecule and the recognition site, a chiral environment. It is to be expected that the most active isomer, in 

When considering in vivo activities, the difference in activity observed for the two enantiomers is neither always and nor exclusively the result of the quality of the Ug-and-receptor fit. It must be kept in mind that in vivo the pharmacokinetic processes (ADME) may account for the observed difference in activity. The interpretation of pharmacological data obtained from in vivo assays should thus be questioned and does not allow anticipating the quality of the ligand-receptor interaction. 

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Experimental facts and their interpretation A Stereoselectivity in biologically active compounds... 

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