Chirality in New Drug Development: Clinical Pharmacokinetic Considerations

There are several clinical pharmacokinetic considerations that are pertinent to the decision to develop either an individual enantiomer or the racemate. In the majority of cases, these considerations favour proceeding down the enantiomer pathway. In the future, it is likely that very few new chiral drugs will be developed as racemates and those that are will come under rigorous scrutiny by the regulatory authorities. As commented recently by Cayen,⁴¹ a member of the pharmaceutical industry, ‘Pharmaceutical companies are very much aware that, in the 1990s, racemate development will be cost ineffective and time-consuming. Regulatory agencies are asking the right questions and taking a very hard look at racemate NCEs New Chemical Entities; the justification must be convincing. Therefore, why ask for trouble?’.