Testing new medicines: from laboratory to clinic Revision Notes | GCSE OCR Foundation Biology

What this lesson covers

Understand the rigorous process of drug development including preclinical testing using cells, tissues and animals, followed by clinical trials with hea...

• Describe the stages of drug development from laboratory to clinic
• Explain why preclinical testing uses cells, tissues and animals
• Compare the purposes of different phases of clinical trials
• Evaluate the importance of testing for toxicity, efficacy and dose

Key ideas to keep in view

Use this lesson to stay inside B6.3 Monitoring and maintaining health while connecting the detail back to the wider B6: Global challenges topic.

• B6: Global challenges
• B6.3 Monitoring and maintaining health
• GCSE OCR Foundation Biology

Lesson notes preview

Read the core explanations from Testing new medicines: from laboratory to clinic before testing yourself from memory.

• Every medicine in your local pharmacy has survived a brutal 10-15 year testing process. Why so long? Because one mistake could harm millions of people. The thalidomide disaster of the 1960s - where a 'safe' morning sickness drug caused severe birth defects - changed everything. Now every potential medicine must prov...
• Think of drug development like building a bridge. You wouldn't let cars cross without testing the materials, checking the design, and gradually increasing the load. The same logic applies to medicines - we start small and work up to human trials only when we're confident it won't cause harm.
• Before any human volunteers get involved, scientists test potential medicines in the laboratory. This preclinical testing happens in three stages, each more complex than the last.
• Stage 1: Cell cultures - Scientists grow human cells in petri dishes and test whether the drug kills the target disease cells without harming healthy ones. This is quick and cheap, but cells in a dish behave differently from cells in a living body.
• Stage 2: Tissue samples - Next, they test on small pieces of human tissue (like skin or liver samples). This gives a better idea of how the drug affects groups of cells working together, but still doesn't show the full body response.
• Stage 3: Live animals - Finally, they test on animals (usually mice, then larger mammals). This reveals how the whole body processes the drug - does it reach the right organs? Does it cause unexpected side effects? How quickly is it broken down?
• Laboratory testing of potential medicines using cells, tissues and live animals to check basic safety and effectiveness before human trials.
• Every stage of testing focuses on three crucial questions. Get any of these wrong, and the drug fails.
• Toxicity - Is it poisonous? Even water can kill you if you drink too much, so scientists need to find the dose where the medicine helps without causing harm. They test increasing doses until they find the level that causes problems - this sets the safety limit.
• Efficacy - Does it actually work? A medicine might be perfectly safe but completely useless. Scientists compare treated groups with untreated controls to see if the drug makes a real difference to the disease.

Continue through the topic

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