Chemical compounds that come as mirror-image pairs are referred to by chemists as chiral or handed molecules.[1] Each twin is called an enantiomer. Drugs that exhibit handedness are referred to as chiral drugs. Chiral drugs that are equimolar (1:1) mixture of enantiomers are called racemic drugs and these are obviously devoid of optical rotation. The most commonly encountered stereogenic unit,[2] that confers chirality to drug molecules are stereogenic center. Stereogenic center can be due to the presence of tetrahedral tetra coordinate atoms (C,N,P) and pyramidal tricoordinate atoms (N,S). The word chiral describes the three-dimensional architecture of the molecule and does not reveal the stereochemical composition. Hence "chiral drug" does not say whether the drug is racemic (racemic drug), single enantiomer (chiral specific drug) or some other combination of stereoisomers. To resolve this issue Joseph Gal introduced a new term called unichiral.[3][4] Unichiral indicates that the stereochemical composition of a chiral drug is homogenous consisting of a single enantiomer.
Many medicinal agents important to life are combinations of mirror-image twins. Despite the close resemblance of such twins, the differences in their biological properties can be profound. In other words, the component enantiomers of a racemic chiral drug may differ wildly in their pharmacokinetic, pharmacodynamic profile.[5][6][7][8] The tragedy of thalidomide illustrates the potential for extreme consequences resulting from the administration of a racemate drug that exhibits multiple effects attributable to individual enantiomers.[9] With the advancements in chiral technology and the increased awareness about three-dimensional consequences of drug action and disposition emerged specialized field "chiral pharmacology". Simultaneously the chirality nomenclature system also evolved. A brief overview of chirality history and terminology/descriptors is given below. A detailed chirality timeline is not the focus of this article.
^Bassindale, A (1984). The Third Dimension in Organic Chemistry. New York: John Wiley, New York. ISBN 047190189X.
^Mislow, Kurt; Siegel, Jay (1984). "Stereoisomerism and local chirality". Journal of the American Chemical Society. 106 (11): 3319–3328. doi:10.1021/ja00323a043. ISSN 0002-7863.
^Gal, Joseph; Lindner, wolfgang (2006). "Chiral drugs from a historical point of view". In Francotte, Eric (ed.). Chirality in drug research. Germany: Wiley-VCH Verlag GmbH & Co. pp. 3–26. ISBN 3-527-31076-2.
^Gal, J (1998). "Problems of stereochemical nomenclature and terminology. 1. The homochiral controversy. Its nature, origins, and a proposed solution". Enantiomer. 3: 263–273.
^Jamali, F.; Mehvar, R.; Pasutto, F.M. (1989). "Enantioselective Aspects of Drug Action and Disposition: Therapeutic Pitfalls". Journal of Pharmaceutical Sciences. 78 (9): 695–715. doi:10.1002/jps.2600780902. ISSN 0022-3549. PMID 2685226.
^Williams, Kenneth M. (1991), Molecular Asymmetry and Its Pharmacological Consequences, Advances in Pharmacology, vol. 22, Elsevier, pp. 57–135, doi:10.1016/s1054-3589(08)60033-2, ISBN 978-0-12-032922-9, PMID 1958505, retrieved 2021-06-03
^Crossley, Roger (1992). "The relevance of chirality to the study of biological activity". Tetrahedron. 48 (38): 8155–8178. doi:10.1016/s0040-4020(01)80486-5. ISSN 0040-4020.
^Gross, Michael (1990), Chapter 34. Significance of Drug Stereochemistry in Modern Pharmaceutical Research and Development, Annual Reports in Medicinal Chemistry, vol. 25, Elsevier, pp. 323–331, doi:10.1016/s0065-7743(08)61610-3, ISBN 978-0-12-040525-1, retrieved 2021-06-03
^Decamp, W (1989). "The FDA perspective on the development of stereoisomers". Chirality. 1 (1): 2–6. doi:10.1002/chir.530010103. PMID 2642032.
chemists as chiral or handed molecules. Each twin is called an enantiomer. Drugs that exhibit handedness are referred to as chiraldrugs. Chiraldrugs that are...
Chirality /kaɪˈrælɪtiː/ is a property of asymmetry important in several branches of science. The word chirality is derived from the Greek χείρ (kheir)...
improved therapeutic efficacy. The switch from a racemic drug to an enantiopure drug is called a chiral switch. In many cases, the enantiomers have distinct...
enantiomers from racemate drugs. For example, levofloxacin is a chiral switch of racemic ofloxacin. The essential principle of a chiral switch is that there...
optically active compounds, including drugs. Another term with the same meaning is optical resolution. The use of chiral resolution to obtain enantiomerically...
one of many chiral forms, so different enantiomers of a chiraldrug molecule bind differently (or not at all) to target receptors. Chirality can be observed...
enantioselective analysis. Chiral analysis includes all analytical procedures focused on the characterization of the properties of chiraldrugs. Chiral analysis is usually...
of drugs (oxazepam, lorazepam, temazepam), thalidomide, and tiaprofenic acid. A brief list of select pharmaceutical drugs that go through chiral inversion...
In stereochemistry, a chiral auxiliary is a stereogenic group or unit that is temporarily incorporated into an organic compound in order to control the...
Chiral column chromatography is a variant of column chromatography that is employed for the separation of chiral compounds, i.e. enantiomers, in mixtures...
reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric...
PMID 10189176. S2CID 38496241. Lin GQ, You QD, Cheng JF, eds. (August 8, 2011). ChiralDrugs: Chemistry and Biological Action. John Wiley & Sons. p. 88. ISBN 9781118075630...
Limited) Ibuprofen Ketoprofen Thalidomide ChiralityChiraldrugsChiral inversion "FDA-sourced list of all drugs with black box warnings (Use Download Full...
Chemical structures of the catecholamines Sympathomimetic drugs (also known as adrenergic drugs and adrenergic amines) are stimulant compounds which mimic...
Skálová L, Szotáková B (December 2004). "Chiral inversion of drugs: coincidence or principle?". Current Drug Metabolism. 5 (6): 517–533. doi:10.2174/1389200043335360...
The chiral pool is a "collection of abundant enantiopure building blocks provided by nature" used in synthesis. In other words, a chiral pool would be...
OCLC 1097808137. Agranat I, Caner H (July 1999). "Intellectual property and chirality of drugs". Drug Discovery Today. 4 (7): 313–321. doi:10.1016/s1359-6446(99)01363-x...
is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds...
Inc. p. 172. Nguyen, Lien Ai; He, Hua; Pham-Huy, Chuong (2016-11-20). "ChiralDrugs: An Overview". International Journal of Biomedical Science. 2 (2): 85–100...
patient. Many drugs are available as both a racemic mixture (equal amounts of both chiralities) and an enantiopure drug (only one chirality). Depending...
tissues and fluids. 50% is excreted unchanged in urine. ChiraldrugsChirality Enantiopure drug Stereochemistry Hamilton R (2015). Tarascon Pocket Pharmacopoeia...
classes of drugs are suspected to be particularly problematic because of their chemistry. Some of these include chiraldrugs, poorly absorbed drugs, and cytotoxic...
in pharmacologic activity between the two enantiomers of a drug. In most cases where a chiral compound is biologically active, one enantiomer is more active...
and the way a drug works depends on what kind of enantiomer it is. Many drugs are chiral and it is important that the shape of the drug matches the shape...
controls synthetic cannabinoids by analog under the Misuse of Drugs Act, 1971 as Class B drugs. Until 2016, synthetic cannabinoids were legally sold in head...
WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO. Lin GQ, You QD, Cheng JF (2011). ChiralDrugs: Chemistry and Biological Action. John Wiley & Sons. p. 120. ISBN 9781118075630...
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