Drug Discovery and Development

This lesson covers how new drugs are discovered, developed, and tested before they can be used to treat patients. It also looks at the sources of drugs — including those derived from plants and microorganisms. This is required knowledge for the AQA GCSE Combined Science Trilogy specification (8464).

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Where Do Drugs Come From?

Many drugs have been discovered from natural sources — plants, microorganisms, and other living organisms:

Drug	Source	Use
Aspirin	Originally extracted from willow bark (contains salicin)	Pain relief and anti-inflammatory
Digitalis	Extracted from foxglove plants	Treats heart conditions
Penicillin	Discovered from the mould Penicillium	Antibiotic — kills bacteria
Quinine	Extracted from cinchona tree bark	Antimalarial drug

Exam Tip: You need to know that aspirin was developed from a chemical found in willow bark and that digitalis comes from foxgloves. These are classic exam examples of drugs from natural sources.

Today, most new drugs are synthesised by chemists in laboratories. However, the starting point is often a compound discovered in nature.

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The Drug Development Process