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An example of such an enantiomer is the sedative thalidomide, which was sold in a number of countries around the world from 1957 until 1961. It was withdrawn from the market when it was found to cause birth defects. One enantiomer caused the desirable sedative effects, while the other, unavoidably [23] present in equal quantities, caused birth ...
One enantiomer of a drug may have a desired beneficial effect while the other may cause serious and undesired side effects, or sometimes even beneficial but entirely different effects. [1] The desired enantiomer is known as an eutomer while the undesired enantiomer is known as the distomer. [ 2 ]
The eutomer is the enantiomer having the desired pharmacological activity, [4] e.g., as an active ingredient in a drug. The distomer , on the other hand, is the enantiomer of the eutomer which may have undesired bioactivity or may be bio-inert.
In some cases, the less therapeutically active enantiomer can cause side effects. For example, ( S -naproxen is an analgesic but the ( R -isomer causes renal problems. [ 31 ] In such situations where one of the enantiomers of a racemic drug is active and the other partner has undesirable or toxic effect one may switch from racemate to a single ...
As examples, esomeprazole is a chiral switch of (±)-omeprazole and levocetirizine is a chiral switch of (±)-cetirizine. While often only one enantiomer of the drug may be active, there are cases in which the other enantiomer is harmful, like salbutamol [11] and thalidomide. The (R) enantiomer of thalidomide is effective against morning ...
For example, the specific rotation of (S)-2-ethyl-2-methyl succinic acid is found to be dependent on concentration; in what is known as the Horeau effect [3] the relationship between mole based ee and optical rotation based ee can be non-linear i.d. in the succinic acid example the optical activity at 50% ee is lower than expected.
Two enantiomers of a generic amino acid that are chiral (S)-Alanine (left) and (R)-alanine (right) in zwitterionic form at neutral pH. In chemistry, a molecule or ion is called chiral (/ ˈ k aɪ r əl /) if it cannot be superposed on its mirror image by any combination of rotations, translations, and some conformational changes.
The drug was withdrawn from world market when it became evident that the use in pregnancy causes phocomelia (clinical conditions where babies are born with deformed hand and limbs). Later in late 1970s studies indicated that the (R)- enantiomer is an effective sedative, the (S)-enantiomer harbors teratogenic effect and causes fetal abnormalities.