Option D - Medicinal Chemistry
D.1 Pharmaceutical products and drug action
Essential idea: Medicines and drugs have a variety of different effects on the functioning of the body.
Understandings In animal studies, the therapeutic index is the lethal dose of a drug for 50% of the population (LD50) divided by the minimum effective dose for 50% of the population (ED50). In humans, the therapeutic index is the toxic dose of a drug for 50% of the population (TD50) divided by the minimum effective dose for 50% of the population (ED50). The therapeutic window is the range of dosages between the minimum amounts of the drug that produce the desired effect and a medically Dosage, tolerance, addiction and side effects are considerations of drug administration. Bioavailability is the fraction of the administered dosage that reaches the target part of the human body. The main steps in the development of synthetic drugs include identifying the need and structure, synthesis, yield and extraction. Drug receptor interactions are based on the structure of the drug and the site of activity.
Applications and skills Discussion of experimental foundations for therapeutic index and therapeutic window through both animal and human studies. Guidance For ethical and economic reasons, animal and human tests of drugs (for LD50/ED50 and TD50/ED50 respectively) should be kept to a minimum |
D.2 Aspirin and penicillin
Essential idea: Natural products with useful medicinal properties can be chemically altered to produce more potent or safer medicines.
Understandings Aspirin: Penicillin: Applications and skills Aspirin Penicillin Guidance: Students should be aware of the ability of acidic (carboxylic) and basic (amino) groups to form ionic salts, for example soluble aspirin. |
D.3 Opiates
Essential idea: Potent medical drugs prepared by chemical modification of natural products can be addictive and become substances of abuse.
Understandings The ability of a drug to cross the blood–brain barrier depends on its chemical structure and solubility in water and lipids. Applications and skills Explanation of the synthesis of codeine and diamorphine from morphine. Guidance: Structures of morphine, codeine and diamorphine can be found in the data booklet in section 37. |
D.4 pH regulation of the stomach
Essential idea: Excess stomach acid is a common problem that can be alleviated by compounds that increase the stomach pH by neutralizing or reducing its secretion
Understandings Non-specific reactions, such as the use of antacids, are those that work to reduce the excess stomach acid. Applications and skills Explanation of how excess acidity in the stomach can be reduced by the use of different bases. Guidance: Antacid compounds should include calcium hydroxide, magnesium hydroxide, aluminium hydroxide, sodium carbonate and sodium bicarbonate. |
D.5 Antiviral medications
Essential idea: Antiviral medications have recently been developed for some viral infections while others are still being researched
Understandings Viruses lack a cell structure and so are more difficult to target with drugs than bacteria. Applications and skills Explanation of the different ways in which antiviral medications work. Guidance: Structures for oseltamivir and zanamivir can be found in the data booklet in section 37. |
D.6 Environmental impact of some medications
Essential idea: The synthesis, isolation, and administration of medications can have an effect on the environment
Understandings High-level waste (HLW) is waste that gives off large amounts of ionizing radiation for a long time.
Applications and skills Describe the environmental impact of medical nuclear waste disposal. Guidance: The structure of oseltamivir is provided in the data booklet in section 37. |
D.7 Taxol—a chiral auxiliary case study
Essential idea: Chiral auxiliaries allow the production of individual enantiomers of chiral molecules.
Understandings Taxol is a drug that is commonly used to treat several different forms of cancer. Applications and skills Explanation of how taxol (paclitaxel) is obtained and used as a chemotherapeutic agent. Guidance: The structure of taxol is provided in the data booklet in section 37. |
D.8 Nuclear medicine
Essential idea: Nuclear radiation, whilst dangerous owing to its ability to damage cells and cause mutations, can also be used to both diagnose and cure diseases.
Understandings Alpha, beta, gamma, proton, neutron and positron emissions are all used for medical treatment. Applications and skills Discussion of common side effects from radiotherapy. Guidance: Common side-effects discussed should include hair loss, nausea, fatigue and sterility. |
D.9 Drug detection and analysis
Essential idea: A variety of analytical techniques is used for detection, identification, isolation and analysis of medicines and drugs
Understandings Organic structures can be analysed and identified through the use of infrared spectroscopy, mass spectroscopy and proton NMR. Applications and skills Interpretation of a variety of analytical spectra to determine an organic structure, including infrared spectroscopy, mass spectroscopy and proton NMR. Guidance: Students should be able to identify common organic functional groups in a given compound by recognition of common drug structures and from IR |