Importance of Steriochemistry

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  • Topic: Stereochemistry, Enantiomer, Chirality
  • Pages : 9 (2419 words )
  • Download(s) : 1540
  • Published : March 7, 2011
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Nowshin Nowaz Rumzhum
Lecturer, Dept. of pharmacy
Stamford University Bangladesh

Md. Wahid Rezwan
ID No: BPH02805674
Batch No: 28th D


Stereochemistry may seem like a trivial subject because differences between stereoisomers are usually subtle. In nature, however, and most importantly, in biological systems such as the human body, these subtle differences have sweeping implications. Most drugs for example, are often composed of a single stereoisomer of a compound, and while one stereoisomer may have positive effects on the body, another stereoisomer may be toxic. Because of this, a great deal of work done by synthetic organic chemists today is in devising methods to synthesize compounds that are purely one stereoisomer.Accordingly, examples of bioequivalence studies based on stereospecific assays have started to appear in the literature. Fortunately, facile stereospecific assays have become available in the last several years for many drugs. Consequently, regulatory agencies have started to take the issue of stereochemistry into consideration in the assessment of bioequivalence, particularly from the standpoint of generic substitution. Amino acids, Lactic acid and Carbohydrates are discussed with reference to their configurations. The importance of the different properties in isomeric forms of some common pharmaceuticals are also examined

1. The importance of stereochemistry in drug action is well-known. Different stereoisomers can have very different biological effects. This section builds on the study of stereochemistry in H2 Chemistry. 2.Learning Outcomes Candidates should be able to:

(a) explain the importance of optical isomerism to drug action (b) understand the terms enantiomers, diastereomers and meso compounds (c) use stereochemical projections (e.g. Fischer and Newman projections) to represent organic molecules

(d) use R, S configurations to label optical isomers
(e) understand the concepts of optical activity and optical purity 3. Learning Outcomes Candidates should be able to:
(a) describe the different conformations of alkanes and cycloalkanes (b) understand the energy barriers to rotation and interconversion among conformational isomers

Importance of stereochemistry
Cisplatin formation of drugs is used to treat cancer. It has no charge so they can pass through the cancer cell membrane, however the transplatin form cannot.Asymmetric and chiral carbon atoms behave differently in the body. Sometimes, only one is needed, but preparing just one of the isomers is difficult. A chiral auxilliary is used, and will take the place of the undesired isomer. To further a companies library of a processed chemical, a mix-and-split process is used to create exponential amounts of the drug

Stereochemistry in Drug Action:

The importance of stereochemistry in drug action is gaining greater attention in medical practice, and a basic knowledge of the subject will be necessary for clinicians to make informed decisions regarding the use of single-enantiomer drugs. Many of the drugs currently used in psychiatric practice are mixtures of enantiomers. For some therapeutics, single-enantiomer formulations can provide greater selectivities for their biological targets, improved therapeutic indices, and/or better pharmacokinetics than a mixture of enantiomers. This article reviews the nomenclature for describing stereochemistry and enantiomers, emphasizes the potential biological and pharmacologic differences between the 2 enantiomers of a drug, and highlights the clinical experience with single enantiomers of the selective serotonin reuptake inhibitors fluoxetine and citalopram....
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