A pharmaceutical company is developing a new painkiller from a plant extract. Before the medicine can be sold to the public, it must pass through a series of stages. Describe the stages that the new medicine must go through before it can be approved for use by patients.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Many modern medicines are developed from natural sources. The active ingredient must be extracted, tested for safety and effectiveness, and approved by a regulatory authority before it can reach patients.
Model answer (5 marks)
1. The active ingredient is first tested in the laboratory on cells or tissues (pre‑clinical testing).
2. The medicine is then tested on animals to check for safety, toxicity and side effects.
3. Clinical trials are carried out on human volunteers or patients.
4. A placebo is used in the trials so the true effect of the medicine can be compared with no treatment.
5. The results are reviewed and approved by a regulatory authority before the medicine can be sold or used by patients.
2. The medicine is then tested on animals to check for safety, toxicity and side effects.
3. Clinical trials are carried out on human volunteers or patients.
4. A placebo is used in the trials so the true effect of the medicine can be compared with no treatment.
5. The results are reviewed and approved by a regulatory authority before the medicine can be sold or used by patients.
Examiner tips
- Use the exact wording from the mark scheme (e.g. "pre‑clinical testing", "placebo"),
- Show the stages in the correct order,
- Keep each point brief but complete,
- Use bullet points or numbered list to show structure.
Common mistakes
- Mixing up the order of pre‑clinical, animal and human trials
- Omitting the placebo requirement
- Using vague terms like "testing" instead of specifying "pre‑clinical" or "clinical"
Mark scheme (5 marks)
- The active ingredient is tested in the laboratory / tested on cells or tissues (preclinical testing)
- The medicine is tested on animals to check for safety / toxicity / side effects
- Clinical trials are carried out on human volunteers / patients
- A placebo is used so that the effect of the medicine can be compared to no treatment / to identify the true effect of the drug
- The results are reviewed / approved by a regulatory authority before the medicine can be sold / used by patients
Related
- All OCR A-Level Chemistry B: Salters (H433) revision notes →
- How to answer a "Describe" question →
- Decode the mark scheme abbreviations →
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