# A scientist is researching a new antifungal medicine extracted from soil bacteria. Explain why the scientist must test the medicine for purity and carry out clinical trials before it can be approved for use in patients.

> OCR A-Level Chemistry B: Salters (H433) — WM What's in a medicine? · Explain · 5 marks

> Soil bacteria produce a range of chemical compounds, some of which have been found to have medicinal properties. One such compound is being investigated as a potential antifungal medicine. Before it can be prescribed to patients, it must pass through several stages of testing and approval.

## Mark scheme (5 marks)

1. The medicine must be tested for purity to ensure it does not contain harmful impurities / contaminants
2. Clinical trials are carried out to test the medicine is safe for use in humans
3. Clinical trials test that the medicine is effective / works as intended against the condition
4. A placebo is used in trials so that results can be compared to patients receiving no active treatment, to determine whether any improvement is due to the medicine itself
5. The trial/approval process ensures the benefits of the medicine outweigh the risks before it is approved for widespread use

## Key terms

- [purity](https://www.gradenine.co.uk/glossary/purity)
- [clinical trial](https://www.gradenine.co.uk/glossary/clinical-trial)

## Related

- [Revision notes for OCR A-Level Chemistry B: Salters (H433)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-scientist-is-researching-a-new-cdb16abd) · Published by Druglandscape Ltd.