Bio paper 1

• In preclinical testing, drugs are tested on human cells and tissues in the lab
• You can't use human cells and tissues to test drugs that affect whole or multiple body systems, e.g. testing a drug for blood pressure must be done on a whole animal because it has an intact circulatory system
• Preclinical testing


  1. Test the drug on animals

  2. Test efficacy (whether the drug works and produces the effect you're looking for)

  3. Test toxicity (how harmful it is)

  4. Find the best dosage (the concentration that should be given, and how often it should be given)
• The law in Britain states that any new drug must be tested on two different live mammals
• Some people think it's cruel to test on animals


  Others believe this is the safest way to make sure a drug isn't dangerous before it's given to humans
• But some people think that animals are so different from humans that testing on animals is pointless
• Clinical trials


  1. Test on healthy volunteers (to make sure it doesn't have any harmful side effects when the body is working normally)

  2. Gradually increase the dose

  3. Test on people suffering from the illness (to find the optimum dose - the most effective dose with few side effects)

  4. Randomly put patients into two groups (one gets the new drug, the other gets a placebo)

  5. Make the trial blind (the patient doesn't know if they're getting the drug or placebo)

  6. Often make the trial double-blind (neither the patient nor the doctor knows until the results are gathered)
• The results of drug testing and drug trials aren't published until they've been through peer review
• Peer review is where other scientists check that the work is valid and has been carried out rigorously