Antibiotics - Developing Drugs: Discovery and Development (GCSE Biology)

Developing Drugs: Discovery and Development

Drug Discovery

Finding New Treatments

• Drug discovery is required to provide new treatments. Research is constantly being done to discover new drugs. Some diseases still have no cures, so we need to find drugs for them. Other diseases have cures, but research continues to find better treatments or find alternatives incase current drugs become ineffective (e.g. if antibiotic resistance develops).
• Many drugs are found in nature. Historically, most drugs have been extracted from plants and microorganisms such as fungi. In modern times, most drugs are synthesised by chemists in the pharmaceutical industry, but the starting point may still be a chemical extracted from a plant.

Examples of Plant Drug Discoveries

There are two examples of drugs from plants that you need to know about:

• Digitalis – digitalis is extracted from foxglove plant leaves. It contains digoxin, which is used to stimulate heart muscle and increase heart rate.
• Aspirin – aspirin is another example of a plant based drug which originates from Willow. Willow was used since Ancient Greece, in order to help with aches and pains. Scientists then discovered that salicylic acid was present in willow. This salicylic acid is the main ingredient in aspirin. It was then extracted and used to create aspirin. Aspirin is taken in the form of a tablet, and is used to reduce pain and inflammation.

Example of Microorganism Drug Discovery

There is one example of a drug from microorganisms that you need to know about:

• Penicillin – penicillin was actually discovered by accident by Alexander Fleming. A mould grew in his lab due to poor hygiene, but Fleming found that the penicillin could be used to make an amazing antibiotic.

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Drug Development

Safety and Efficacy

After a drug is discovered, it must be developed and trialled in order to ensure that it is effective in treating disease, and also safe to use. The use of a drug depends on three aspects:

1. Dosage – it is important to work out the optimum dosage for a drug. Too low a dose will mean that the drug is ineffective, but too high a dose can lead to dangerous side effects and toxicity.
2. Toxicity – it is important to check for toxic side effects of the drug. For example, some drugs might lead to mutations and increase risk of cancer, whilst other drugs have unpleasant side effects such as stomach aches. We need to check for both short and long term side effects.
3. Efficacy – it is important to actually test how effective the drug is against the disease. Launching a drug is an expensive process, so it needs to have a significant benefit in treating patients before it can be approved.