Chiral switches

Developments in synthetic and analytical chemistry have provided the tools to differentiate between two enantiomers (mirror images) of drugs or betwee n the parent compound and metabolite(s) with respect to desired and undesir ed pharmacological effects. Several drugs are now marketed or being develop ed as single enantiomers in place of a previous racemic mixture, a process known as "chiral switching". It is easier to understand "pure" as opposed t o "mixture" pharmacology but whether the promise of chiral (and metabolite) switches will translate into real clinical advances remains to be seen.