Chiral drugs

Louis Pasteur, foto av Paul Nadar, Crisco edit

Cahn-Ingold-Prelog convention

Easson-Stedman Model

D-Penicillamine

L-Penicillamine

Ketamine enantiomers

Chiral drugs are pharmaceutical compounds that exhibit chirality, meaning they have non-superimposable mirror images known as enantiomers. These enantiomers can have significantly different effects in biological systems, making the study and application of chiral drugs crucial in pharmacology and medicine.

Chirality in Chemistry

Chirality is a geometric property of some molecules and ions. A chiral molecule or ion is non-superimposable on its mirror image. The presence of an asymmetric carbon atom, also known as a chiral center, typically gives rise to chirality. This concept is fundamental in organic chemistry and is essential for understanding the behavior of chiral drugs.

Enantiomers

Enantiomers are pairs of molecules that are mirror images of each other but cannot be superimposed. They are a type of stereoisomer. In the context of chiral drugs, enantiomers can have different pharmacokinetics and pharmacodynamics, leading to variations in their therapeutic and adverse effects. One enantiomer may be more active or less toxic than the other, which is why the distinction is important in drug development and usage.

Pharmacological Implications

The different effects of enantiomers are due to their interactions with chiral environments in the body, such as receptors, enzymes, and proteins. For example, the drug thalidomide has one enantiomer that is effective as a sedative, while the other causes severe birth defects. This highlights the importance of chirality in drug safety and efficacy.

Synthesis and Separation

The synthesis of chiral drugs can be challenging due to the need to produce a specific enantiomer. Techniques such as chiral resolution, asymmetric synthesis, and the use of chiral catalysts are employed to obtain the desired enantiomer. Additionally, advances in chromatography and other separation methods have improved the ability to isolate enantiomers.

Regulatory Considerations

Regulatory agencies like the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) require detailed information on the chirality of drugs. This includes the pharmacological activity of each enantiomer, their pharmacokinetics, and potential side effects. The development of single-enantiomer drugs is often preferred to ensure safety and efficacy.

Examples of Chiral Drugs

Several well-known drugs are chiral, including:

• Ibuprofen - A nonsteroidal anti-inflammatory drug (NSAID) with one active enantiomer.
• Omeprazole - A proton pump inhibitor used to treat acid reflux, available as a racemic mixture and as the single enantiomer esomeprazole.
• Albuterol - A bronchodilator used in the treatment of asthma, with one enantiomer being more active.

Related Pages

• Chirality (chemistry)
• Enantiomer
• Pharmacokinetics
• Pharmacodynamics
• Thalidomide
• Ibuprofen
• Omeprazole
• Albuterol

See Also

• Stereochemistry
• Asymmetric synthesis
• Chiral resolution
• Drug development