Pharmaceutical products and drug action

Nature of science:

Risks and benefits—medicines and drugs go through a variety of tests to determine their effectiveness and safety before they are made commercially available. Pharmaceutical products are classified for their use and abuse potential. (4.8)

• 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 unacceptable adverse effect.
• 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.

• In some countries certain drugs are only available with prescription while in other countries these same drugs are available over the counter.

Theory of knowledge:

• The same drug can be identified by different names. Are names simply labels or do they influence our other ways of knowing?
• Drugs trials use double blind tests. When is it ethically acceptable to deceive people?
• All drugs carry risks as well as benefits. Who should ultimately be responsible for assessing these? Public bodies can protect the individual but also limit their freedom. How do we know what is best for society and the individual?

Aims:

• Aim 9: There have been advances in the development of pharmaceuticals, but there are many limitations to their impact and reach.
• Aim 10: The development of new medicines is often done in collaboration with biologists and physicists.

• Discussion of experimental foundations for therapeutic index and therapeutic window through both animal and human studies.
• Discussion of drug administration methods.
• Comparison of how functional groups, polarity and medicinal administration can affect bioavailability.

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.