46. Drug Development and Testing

GCSE Biology - Drug Development and Testing

Drug development is a rigorous process designed to ensure that new medications are safe and effective. It involves transitioning from natural discoveries to highly controlled laboratory and human testing.

1. Origins of Drugs

Many modern medicines were originally derived from plants and microorganisms:

• Aspirin: Developed from a chemical found in the bark of willow trees; used as a painkiller and to lower fevers.

• Digitalis: Extracted from foxgloves; used to treat heart conditions like heart failure.

• Penicillin: Discovered by Alexander Fleming from the Penicillium fungus; the world's first widely used antibiotic.

2. Key Testing Criteria

Before a drug can be approved, scientists must evaluate three critical factors:

• Efficacy: How well the drug produces the intended effect (e.g., killing bacteria or reducing pain).

• Toxicity: How harmful the drug is and what side effects it may cause.

• Dosage: The specific concentration or amount of the drug that should be administered to maximize benefits while minimizing risks.

3. Stages of Drug Testing

Pre-clinical Testing (No Humans)

1. Human Cells and Tissues: Drugs are first tested in a lab on live cells. This is cheap and fast but doesn't show how the drug affects a whole body system.

2. Live Animals: In the UK, drugs must be tested on two different live mammals (e.g., mice and rabbits) to assess toxicity and efficacy in a complex organism.

Clinical Testing (Humans)

3. Healthy Volunteers: A very low dose is given to healthy people to check for safety and side effects. The dose is gradually increased to find the maximum safe dosage.

4. Patients: The drug is then given to people suffering from the target illness. This helps determine the optimum dosage—where efficacy is highest and toxicity is lowest.

4. Ensuring Fair Results

To prevent bias and ensure the results are valid, clinical trials use specific protocols:

• Placebo: A "fake" drug (e.g., a sugar pill) that looks identical to the real medication but contains no active ingredients.

• Blind Trial: The volunteers do not know if they are receiving the real drug or the placebo.

• Double-blind Trial: Neither the volunteers nor the doctors know who has which substance until the trial is over. This prevents unconscious bias in reporting or observing symptoms.

• Peer Review: Once testing is complete, the results are analyzed by independent scientists to verify that the study was fair and the claims are accurate.

Summary Table: Stages of Testing