Chirality in pharmaceutical synthesis 66-67 Flashcards
Why does the three-dimensional structure of the drug determine the pharmacological activity of a drug?
Biological molecules have complex three-dimensional structures that bind to a drug molecule in only one possible way.
What advantages does the production of a single isomer with the correct pharmacological activity present?
- Risks from undesirable side effects are reduced.
- Drug doses are reduced. When a drug containing a mixture of two optical isomers is prescribed, half of the drug is often wasted in the body because only one of the isomers has the desired therapeutic effect. Making a drug containing one of the optical isomers reduces the required dose by half.
What is the difference between a chiral compound formed in a lab and one produced naturally?
When a chiral compound is synthesised in the laboratory, a mixture of optical isomers is usually formed. But when the same material is made naturally in a living system, it is produced as a single optical isomer.
Why is it hard to separate optical isomers?
Separation is difficult because optical isomers usually have the same or very similar physical properties - melting points, boiling points and solubilities.
What do some separation techniques of optical isomers include?
Separation techniques include enzymes, electrophoresis and chromatography. The techniques take a significant amount of time and are costly.
Explain the use of enzymes and biological catalysts in modern chiral synthesis.
Nature is good at making single optical isomers. If a synthetic route can be designed using enzymes, then a single isomer can be produced.
- Drug manufacturers can use purified enzymes or enzyme-containing microorganisms to biocatalyse any reaction step that produces a chiral carbon.
Explain chiral pool synthesis in modern chiral synthesis.
This technique makes use of the pool of naturally occurring
chiral molecules within the synthetic route. The chirality of the original molecule can lead to the formation of a product that is a single, pure optical isomer. Common starting materials used in chiral synthesis include natural a-amino acids and sugars.
Explain the use of transition element complexes.
These are transition metal complexes to produce chiral catalysts.
What are the uses of ibuprofen, what does it do?
Ibuprofen is a type of anti-inflammatory drug that targets both bone and muscle pain. Ibuprofen controls pain by blocking messages to the brain and reducing swelling or inflammation. Ibuprofen is commonly used to relieve headache, back pain and period pain, and to treat cold and flu symptoms and arthritis.
Why can ibuprofen be sold with both of its optical isomers?
One of the optical isomers of ibuprofen relieves pain much more effectively than the other.In the body the less active form of ibuprofen is converted to the pharmacologically active isomer.
How many optical isomers will there be if there are two chiral carbons?
Four optical isomers.
