AQA · GCSE · Biology

    Course version: 8461 · Version from Sept 2018

    Students should be able to describe the process of discovery and…

    Full specification wording

    Discovery and development of drugs: Students should be able to describe the process of discovery and development of potential new medicines, including preclinical and clinical testing.

    New medicines are developed through a sequence of stages.

    Checked against the AQA 8461 specification (opens in a new tab) on .

    • Point 1 of 9
    • 4 key terms

    Study notes

    From the checked teaching notes for this specification point.

    The idea

    New medicines are developed through a sequence of stages. Potential drugs may be discovered from traditional plant or microorganism sources, or synthesised in the laboratory. Preclinical testing uses cells, tissues and live animals to assess toxicity, dosage and efficacy before any human trial. Clinical testing then proceeds in phases: a small number of healthy volunteers checks safety and side effects; a larger group of patients checks effectiveness and optimum dose; and larger-scale trials compare the new drug with existing treatments, often using placebos and randomisation to reduce bias. If results show the drug is safe and effective, it can be licensed and marketed.

    What earns the marks

    • Discovery: potential drugs are identified from plant or microorganism extracts, or designed and synthesised in the laboratory.
    • Preclinical testing: the drug is tested on cells, tissues and live animals to assess toxicity, safety and effective dose before human trials.
    • Clinical testing phase 1: a small number of healthy volunteers is used to check safety and side effects.
    • Clinical testing phase 2: a larger group of patients is used to test effectiveness and find the optimum dose.
    • Clinical testing phase 3: large-scale trials compare the new drug with existing treatments, often using placebos and random allocation.
    • If the drug is shown to be safe and effective, it is licensed and can be prescribed; otherwise development stops.

    Common mistakes and how to put them right

    • Reversing preclinical and clinical testing.

      Put it right by stating that preclinical testing occurs before any human testing.

    • Thinking clinical trials use only healthy volunteers.

      Put it right by explaining that healthy volunteers are used in early safety trials, while patients are used to test effectiveness.

    • Believing a drug is tested on humans as soon as it is discovered.

      Put it right by describing the prior preclinical safety and toxicity checks.

    Exam tips

    • Present the stages in a clear sequence: discovery, preclinical, clinical phases, licensing.
    • State the purpose of each stage, such as safety, dosage or effectiveness, rather than just naming it.
    • Mention placebos and randomisation when explaining how bias is reduced in clinical trials.

    Try the lesson

    The start of the Discovery and development of drugs: Students should be able to describe the process of discovery and development of potential new medicines, including preclinical and clinical testing. lesson, made from checked teaching notes for this specification point.

    Have a go first

    In the development of a new medicine, what is tested during preclinical testing?

    Listen

    New medicines are developed through a sequence of stages. Potential drugs may be discovered from traditional plant or microorganism sources, or synthesised in the laboratory. Preclinical testing uses cells, tissues and live animals to assess toxicity, dosage and efficacy before any human trial. Clinical testing then proceeds in phases: a small number of healthy volunteers checks safety and side effects; a larger group of patients checks effectiveness and optimum dose; and larger-scale trials compare the new drug with existing treatments, often using placebos and randomisation to reduce bias. If results show the drug is safe and effective, it can be licensed and marketed. A strong answer earns marks for these points. Discovery: potential drugs are identified from plant or microorganism extracts, or designed and synthesised in the laboratory. Preclinical testing: the drug is tested on cells, tissues and live animals to assess toxicity, safety and effective dose before human trials. Clinical testing phase 1: a small number of healthy volunteers is used to check safety and side effects. Clinical testing phase 2: a larger group of patients is used to test effectiveness and find the optimum dose. A common slip: Reversing preclinical and clinical testing. Instead, stating that preclinical testing occurs before any human testing. Exam tip: Present the stages in a clear sequence: discovery, preclinical, clinical phases, licensing.

    See it

    A top-down flowchart with seven nodes. The first node is discovery, where potential drugs are identified from plant or microorganism extracts or synthesised in the laboratory. An arrow leads to preclinical testing on cells, tissues and live animals. An arrow leads to clinical phase 1, using a small number of healthy volunteers. An arrow leads to clinical phase 2, using a larger group of patients. An arrow leads to clinical phase 3, large-scale trials with placebos and randomisation. From this final testing node two arrows branch: one to a node saying the drug is safe and effective, so it is licensed and prescribed; the other to a node saying it is not safe or effective, so development stops.
    The sequence of stages in discovering and developing a new medicine, from discovery through preclinical and clinical testing to licensing or stopping development.

    Key words

    Say what each word means before you turn the card.

    Drug discovery

    Try answering aloud or in your head before turning the card.

    Preclinical testing

    Try answering aloud or in your head before turning the card.

    Clinical trials

    Try answering aloud or in your head before turning the card.

    Safety, efficacy and licensing

    Try answering aloud or in your head before turning the card.

    See every definition
    Drug discovery
    Potential drugs are identified from plant or microorganism extracts, or designed and synthesised in the laboratory.
    Preclinical testing
    The drug is tested on cells, tissues and live animals to assess toxicity, safety and effective dose before human trials.
    Clinical trials
    Testing proceeds in phases: healthy volunteers check safety and side effects, patients test effectiveness and optimum dose, and large-scale trials compare the new drug with existing treatments.
    Safety, efficacy and licensing
    If results show the drug is safe and effective, it can be licensed and marketed; otherwise development stops.

    Label the diagram

    Some boxes have lost their names. Pick the right name for each number.

    The diagram again, with 3 boxes numbered instead of named. A top-down flowchart with seven nodes. The first node is discovery, where potential drugs are identified from plant or microorganism extracts or synthesised in the laboratory. An arrow leads to preclinical testing on cells, tissues and live animals. An arrow leads to clinical phase 1, using a small number of healthy volunteers. An arrow leads to clinical phase 2, using a larger group of patients. An arrow leads to clinical phase 3, large-scale trials with placebos and randomisation. From this final testing node two arrows branch: one to a node saying the drug is safe and effective, so it is licensed and prescribed; the other to a node saying it is not safe or effective, so development stops.

    • 1Box 1

    • 2Box 2

    • 3Box 3

    0 of 3 labelled

    There is more to this lesson

    The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.

    Carry on with the full lesson

    A week of Premium from your first lesson · Then the free plan continues · No card, no charge

    Test your understanding of Discovery and development of drugs: Students should be able to describe the process of discovery and development of potential new medicines, including preclinical and clinical testing.

    Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.

    Take topic quiz

    A week of Premium from your first lesson · Then the free plan continues · No card, no charge

    Start free

    Cookies on MasteryMind

    Essential cookies keep you signed in.

    Analytics and advertising cookies stay off unless you accept.

    Read our Privacy Policy.