Science test tubes

How are new drugs discovered and developed?

Most of us rely on the idea that when we have a health issue, the pharmaceutical industry will have developed a new drug to treat our illness (or at least the symptoms). But how do new drugs get discovered and how do they they find their way onto the market?

1. Discovery and Development

Generally scientists discover new drugs thanks to new insights into diseases found via medical studies, finding unanticipated effects of existing treatments, or doing a barrage of tests on a wide array of molecular compounds using advanced tools like‘s microplate readers to see how they could have beneficial effects against any of a large number of diseases.

Once the researchers have narrowed down the compounds that they have determined to be worth further examination they move into the development stage where they gather information about how the compound is absorbed, distributed, metabolised, and excreted by the body, which gives them insight into the potential benefits of the drug and how it might work.

This is the stage where they will determine the most effective dosage and how best to administer the drug (via pill or injection), as well as the possible side effects and how it interacts with other treatments already on the market.

2. Preclinical Research

It is vital that pharmaceutical firms uncover any potential side effects and the chance of the new drug to cause serious harm, also known as toxicity. These tests are done in the preclinical phase of research, both “in vitro” (ie. in laboratory tests in dishes and test-tubes) and “in vivo” (ie. in living organisms like rats or monkeys).

Once these safety and toxicity tests have been completed to a regulated standard, the researchers will determine whether to scrap the new compound or take it onto the next stage – clinical research.

3. Clinical Research

There is no substitute for human testing to examine how effectively a new drug works, and researchers design clinical trials to test how well a drug works for its stated purpose and whether any new adverse effects become apparent. Depending on the drug, these trials can include thousands of people and last for up to four years. But at the end, it is generally clear whether the drug is fit for purpose and should be sold on the market.

4. Drug review and certification

Once the development and testing of the new drug is complete, the pharmaceutical companies must get it approved by the drug licensing board in each country (such as the FDA in the US and the Medicines and Healthcare products Regulatory Agency (MHRA) and the European Medicines Agency (EMA) in the UK/EU) before they are able to sell it to the public or make it available to be prescribed by doctors.

The regulatory body will go through all the test results provided the the drug-maker and may ask for further clarifications before finally making its decision.

Photograph by Philippe Delavie