(39) GCSE Biology Revision "Testing Medicines"

Introduction to Medicine Development

• Overview of new medicine discovery and testing process.

• Previous video covered antibiotics and painkillers.

• Continuous development of new medicines requires extensive testing.

Sources of New Medicines

Historical Origins

• Medicines previously sourced from plants and microorganisms.

  • Example: Digitalis from the foxglove plant.

  • Example: Aspirin extracted from willow trees.

  • Example: Penicillin discovered by Alexander Fleming from Penicillium mold.

Modern Methods

• Majority of new drugs synthesized by chemists in pharmaceutical companies.

• Often begin with chemical compounds from plants.

Drug Testing Stages

Importance of Testing

• Every new drug must be tested for:

  • Toxicity: Ensure it's safe for human use.

  • Effectiveness: Confirm it successfully treats the targeted disease.

  • Dosage: Determine the optimal dose for treatment.

Preclinical Testing

• Conducted before human trials, involving:

  • Tests on cells and tissues.

  • Experiments on live animals to evaluate safety.

Clinical Testing

Initial Phase

• Commences after preclinical success.

• Very low doses administered to healthy volunteers to test for safety in humans.

Further Testing

• If safe, continues to determine the best dosage for effective treatment with minimal side effects.

Placebos in Drug Testing

The Role of Placebos

• Definition: A placebo is an inactive tablet or injection.

  • Patients may improve due to the belief they are receiving treatment.

Double-Blind Trials

• Involves two groups:

  • Test group receives the active drug.

  • Control group receives the placebo mimicking the active drug.

• Neither patients nor doctors know who receives which treatment to prevent bias in observations.

Conclusion

• Summary of how new medicines are discovered and tested.

• Additional resources available in supplementary workbook.