Chirality
- Omeprazole(Prilosec) andEsomeprazole(Nexium)
- Citalopram(Celexa / Cipramil) andEscitalopram(Lexapro / Cipralex)
- Zopiclone(Imovane) andEszopiclone(Lunesta)
- Modafinil (Provigil) and Armodafinil (Nuvigil) — sulfur is the chiral center in
modafinil, instead of carbon.
Many chiral drugs must be made with high enantiomeric purity due to potential side-effects
of the other enantiomer. (The other enantiomer may also merely be inactive.)
Consider a racemic sample of thalidomide. One enantiomer was thought to be effective
against morning sickness while the other is now known to be teratogenic. Unfortunately, in
this case administering just one of the enantiomers to a pregnant patient would still be very
dangerous as the two enantiomers are readily interconvertedin vivo. Thus, if a person is
given either enantiomer, both the D and L isomers will eventually be present in the patient’s
serum and so chemical processes may not be used to mitigate its toxicity.
Figure 98 Thalidomide enantiomers.
32.11 See also
Optical activity^6
6 Chapter 33 on page 143