Skip to content

Help and information

This topic takes on average 55 minutes to read.

There are a number of interactive features in this resource:

Topic last updated: 24 Nov 2021
    • Ico Chemistry Chemistry
    • Ico Science Science
    • 16+
    • 55

Making medicines

  of  8

Research and development

Discovering a new medicine

Once a chemical or biological molecule that might treat a disease has been identified it will be tested to see how good it is likely to be in treating that disease. Tests might use an antibody or cultured cells to look for the desired activity.

Preclinical development

The promising compounds - often called 'leads' - are then made in small quantities and studied in the laboratory. Initially they will be tested on cell cultures. These are collections of living cells that respond as though they were part of an animal or human. The scientists can determine if the molecules are toxic (poisonous) and if they have any potential therapeutic effects (likely to treat the disease).

At the same time tests will be carried out by chemists and pharmacists to investigate how easily the compounds can be made, how likely they are to be absorbed when given orally (by mouth), and whether there might be other problems with the manufacture of a medicine made from these compounds.

Eventually, after several months of tests, a few molecules will be identified as being the most promising to become an effective medicine to treat the particular disease. These will be tested more rigorously, including tests on animals. These tests will look at whether the medicine is likely to be toxic when given every day for a long time, if it might cause cancer, and if it is likely to cause any damage to the fetus if given to pregnant women.

Before a new compound can be given to humans, tests have to be done to find out:

  • whether it is likely to be effective
  • whether it is acceptably safe
  • whether is is sufficiently stable
  • how it is going to be absorbed and excreted by the body

The different stages of research and development are explained in more detail in the animated timeline below.

Create your own Research and Development Timeline

Use this card sort activity to clarify your understanding of the various activities that go on to discover and develop a new medicine.
Cut out the individual statements and arrange them into a time line. The Careers Matrix on page 9 will also help you get an idea of where things fit in.

Download the card sort activity (pdf, 127KB)