Editing Thalidomide (section)

=== Chirality and biological activity ===
Thalidomide is provided as a [[racemic mixture]] of two [[enantiomer]]s; while there are reports that only one of the enantiomers may cause birth defects, the body converts each enantiomer into the other through mechanisms that are not well understood.<ref name=toxmech2009/> The (R)-enantiomer has the desired sedative effect while the (S)-enantiomer harbors embryo-toxic and teratogenic effects. Attempting to extract solely ''R''-thalidomide does not remove the risk of birth defects, as it was demonstrated that the "safe" ''R''-thalidomide undergoes an ''in vivo'' [[chiral inversion]] to the "teratogenic" ''S''-thalidomide. Under biological conditions, the enantiomers interconvert (''bidirectional chiral inversion'' – (R)- to (S)- and vice versa).<ref>{{Cite book |url=https://www.worldcat.org/oclc/52515592 |title=Stereochemical aspects of drug action and disposition |vauthors=Branch SK, Eichelbaum M, Testa B, Somogyi A |date=2003 |publisher=Springer |isbn=978-3-540-41593-0 |location=Berlin |oclc=52515592}}</ref><ref>{{Cite web |date=20 August 2022 |title=Thalidomide |url=https://chiralpedia.com/blog/thalidomide/ |url-status=live |archive-url=https://web.archive.org/web/20220827093228/https://chiralpedia.com/blog/thalidomide/ |archive-date=27 August 2022 |access-date=27 August 2022 |website=Chiralpedia |language=en-US}}</ref>