Drug design and development

Question 1

Step 1: Discovery and development

Answer 1

New drugs are discovered through new insights into a disease, testing of molecular compounds, existing treatments with unanticipated effects, and new technologies. Laboratory experiments are conducted to find out more about promising compounds.

Question 2

Step 2: Pre-clinical trials

Answer 2

Testing is carried out in-vitro (in test tube/cell culture) or in-vivo (in animal studies) to investigate whether a drug has the potential to cause serious harm, called toxicity. They also determine dosing levels for tests involving humans.

Question 3

Step 3: Clinical trials

Answer 3

Four phases of trials where the drug is tested on humans, each involving more participants and lasting for a longer time.

Question 4

Phase I

Answer 4

Trials are conducted on a small number of healthy volunteers (or patients with a disease/condition), aiming to investigate how the drug interacts with the human body (pharmacokinetics). They are also used to identify common or short-term side effects, and determine the safety and tolerability of the drug.

Question 5

Phase II

Answer 5

Trials are conducted on up to several hundred patients with a disease/condition, helping to refine dosage and identify new side effects. These provide additional safety data for the design of the next phase of research.

Question 6

Phase III

Answer 6

Randomised, double-blind, placebo-controlled trials are conducted on several hundreds to thousands of patients with a disease/condition, aiming to provide ‘proof of concept’ that a drug is actually effective.

Question 7

Phase IV

Answer 7

Post-marketing surveillance involving several thousands of patients with a disease/condition, conducted after the drug has been approved by authorities. They are used to detect long-term or rarer side effects, characterise any drug interactions, refine dosage and compare the effects in different populations.

Question 8

Animal models

Answer 8

Living organisms that are used to understand the disease process and test new drugs, without the risk of harming a human. Can be used to simulate a variety of human diseases, although psychological conditions are hard/impossible to reproduce in animals.