Question

Describe the importance of Thalidomide in understanding the importance of chiral drugs. Besides Thalidomide, what other drugs are chiral drugs and how do the enantiomers function and or react differently?

Answer 1

Thalidomide is a medicine that initially was used as sedative and nausea reliever during the first three month of pregnancy at the beginning of the 1960s, its molecular formula is C₁₃H₁₀N₂O₄. As the years passed, it was detected that this medication was causing malformations in the children of the women who consumed it. Later, it was discovered that the comercialized medicine was a racemic mixture of the two enantiomers of Thalidomide, two molecules with the same structure but different geometric arrangement, the (R)-Thalidomide that produces the desired effect, and the (S)-Thalidomide that produces teratogenic effects, seriously affecting the fetus during the early stages of gestation. Thousands of children around the world were affected, causing huge social and economic repercussions. This disaster taught to the pharmaceutical industry that the chirality of the molecules used as medicines can drastically affect the metabolism mechanisms of them. From this incident, enantioselective processes have been developed in the medicine synthesis and efficient separation processes of racemic mixtures have been designed. Another interesting example about the importance of chirality in medicine is ibuprofen, because only the S(+)-ibuprofen enantiomer has the desired analgesic activity.