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The eudysmic ratio (also spelled eudismic ratio) is a common term in pharmacology, chemistry, and molecular biology. The eudysmic ratio describes the difference in pharmacologic activity between the two enantiomers of a drug. When enantiomers are formed non-selectively and the resulting product contains an equal quantity of each enantiomer it is called a racemic mixture. In pharmacology it is frequently, though not always, the case that one enantiomer of a chiral drug has greater pharmacological activity than the other. The eudysmic ratio is a mathematical equation that quantitatively measures the difference in this activity. A eudysmic ratio significantly differing from 1 means that there is a difference in activity between the two enantiomers. == Terminology == The eutomer is the chiral enantiomer having the desired pharmacological activity,〔Wermuth CG, Ganellin CR, Lindber P, Mitscher LA (1998). ''Glossary of Terms used in Medicinal Chemistry (IUPAC Recommendations 1998).'' In: ''Pure & Appl. Chem.'' 70:1129-1143.〕 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.〔Hermann J. Roth, Christa E. Müller, Gerd Folkers: ''Stereochemie und Arzneistoffe'', Wissenschaftliche Verlagsgesellschaft Stuttgart, 1998, S. 80−82, ISBN 3-8047-1485-4.〕 It is often the case that only a single one of the enantiomers contains all of the wanted bioactivity, the distomer is often less active, has no desired activity or may even be toxic. In some cases the eudysmic ratio is so high that it is desired to separate out the two enantiomers instead of leaving it as a racemic product. It is also possible that the distomer is not simply completely inactive but actually antagonizes the effects of the eutomer. Alternatively, it is possible that the distomer converts in the body into the eutomer, at least partly. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「eudysmic ratio」の詳細全文を読む スポンサード リンク
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