Chiral Switch: Pure Enantiomers of Drugs instead of Racemic Mixtures

Overview

Chirality of drugs, particularly the comparison of efficacy of enantiomers and their racemic mixtures,has become an object of serious interest of pharmaceutical researchers in recent ten or fifteen years.Advances in chemical technologies connected with the synthesis, separation, and analysis of pureenantiomers from racemates, together with administrative regulatory measures, have resulted inan increase in the number of newly registered chiral drugs containing only one of the enantiomers.Besides new chemical entities, many „old“ racemates are being re-evaluated as potentially newsources of pure enantiomers which should improve the therapeutic profile of the drug. Due to thisreplacement of a racemic mixture with a pure enantiomer, the literature lists both drugs containinga racemate and drugs containing only one of the enantiomers.Nevertheless, the required therapeuticeffect is not always achieved, and unexpected undesirable effects have also occurred. The papersummarizes therapeutic and economic problems concerning chiral switch drugs.

Key words:
chiral drugs – racemates – enantiomers – economic aspects