from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. Of or relating to a chemical compound that contains equal quantities of dextrorotatory and levorotatory forms and therefore does not rotate the plane of incident polarized light.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. containing equal amounts of dextrorotatory (D) and levorotatory (L) stereoisomers and therefore not being optically active; typically, will be synthetic rather than natural

from the GNU version of the Collaborative International Dictionary of English

  • adj. Pertaining to, or designating, an acid found in many kinds of grapes. It is also obtained from tartaric acid, with which it is isomeric, and from sugar, gum, etc., by oxidation. It is a sour white crystalline substance, consisting of a combination of dextrorotatory and levorotatory tartaric acids.

from The Century Dictionary and Cyclopedia

  • Pertaining or relating to grapes in clusters, or to racemes.
  • In chem., composed of two optically opposite isomeres. The typical case is that of racemic acid (see below), but racemic forms are of frequent occurrence among organic compounds. The racemic form does not act on polarized light.


from Wiktionary, Creative Commons Attribution/Share-Alike License

From French racémique, from Latin racēmus ("cluster or bunch of grapes") + -ique or from raceme +‎ -ic.


  • Rebecca arrives in less than a minute and asks the nurses to get a racemic epinephrine neb.

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  • Since random samples from natural and artificial (Urey-Miller) have racemic yields.

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  • Resting on a wooden dais throughout the ceremony, the synthetic psychostimulant was warmly praised by Harvard president Drew Faust, who called Adderall a stirring testament to what the human mind can achieve when chemically altered by a combination of dextroamphetamine and racemic DL-amphetamine salts.

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  • As observed in all consequent experiments, both left-handed (L) and right-handed (D) optical isomers were created in a racemic mixture

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  • The 2 enantiomers of racemic tramadol function in a complementary manner to enhance the analgesic efficacy and improve the tolerability profile of tramadol.

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  • Crystallography volunteers enantiomorphic space groups P3 (1) 21 and P3 (2) 21 with respective all right-handed and all left-handed 3-fold screw axies, no racemic screw axes, no conflicting screw axes.

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  • When switching dosage forms, if the prescriber does not obtain the desired therapeutic endpoint in spite of education about the extensive differences in inhalers, there are alternatives - use of a spacer, increased dose causing more side effects or switching to Xopenex, the R- enantiomer which is the active portion of the racemic albuterol.

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  • Nexium is only the S-enantiomer; Prilosec is a racemic mixture.

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  • For example benzedrine inhalers (racemic amphetamine) could be bought OTC until the 1950s.

    Boing Boing

  • I'm just struck by the fact that someone claims to have majored in chemistry but writes as if he doesn't understand *why* enantiomers are formed in racemic mixtures here's a hint: kinetics and thermodynamics.

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