a racemic mixture has 50-50% of the 2 different enantiomers. There are racemate drugs out there in the world. The misunderstanding I have is that usually 1 out of the 2 enantiomers molecules have a different reaction with the body, so if you perform racemisation to form a racemic mixture, ain’t that drug going to be still harmful in your body ? Or does FDA not accept racemic mixture where 1 of the enantiomers in it are harmful to the body? Thus they only accept racemic mixture where both enantiomers have to perform the same therapeutic effect on the body ?

  • $\begingroup$ chemistry.stackexchange.com/questions/105/… $\endgroup$
    – Mithoron
    Commented Nov 5, 2019 at 19:04
  • $\begingroup$ The 'wrong' enantiomer is far more often inactive than actually harmful. FDA does not usually approve racemic mixtures unless the compound racemises under physiological conditions. $\endgroup$
    – Waylander
    Commented Nov 5, 2019 at 19:12
  • 1
    $\begingroup$ Thalidomide is one classic example which is an approved medicine. It racemizes in the body and one of the enantiomers damaged a lot of babies in pregnant mothers. It is called thalidomide tragedy. $\endgroup$
    – ACR
    Commented Nov 6, 2019 at 0:46


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