News Release

New drug discoveries are closely linked to the quality of lab procedures

High-quality lab procedures are even more crucial to identifying effective drugs than previously thought, new research from the University of Bath has revealed

Peer-Reviewed Publication

University of Bath

In their quest to find new drugs to treat deadly diseases, scientists study millions of molecules at high speed at the same time. Often it is enzymes that are investigated as targets in these 'high-throughput' screenings.

New research from the University of Bath in the UK suggests the quality of the lab procedure (or assay) used for these screenings (measured by the "Z' value") has a much bigger impact on the ability to identify effective new molecules than was previously thought. The Z'-factor - which can never be greater than 1.0 - is a statistical measure of the researchers' ability to see the required signal. It is used to judge whether the response in a particular assay is large enough to warrant further attention.

As a result of the new study, pharmaceutical companies and other labs around the world will be under pressure to refine their techniques for investigating new drug candidates.

In recent years, there has been an explosion of studies involving enzymes. These studies aim to identify molecules that can be developed into new drugs for treating cancers, infectious diseases and neurodegenerative diseases, amongst other conditions.

"There are a lot of diseases out there for which there is no treatment or the treatments aren't very good," said Dr Matthew Lloyd, who led the study from the University's Department of Pharmacy and Pharmacology. "This explains why there is such a big drive to develop new treatments using high-throughput screening."

In a paper published this month in the Journal of Medicinal Chemistry, Dr Lloyd identifies 75 examples of 'hit' molecules that went on to the next stage of early drug discovery. This is the first time high-throughput screening involving enzymes has been subject to such a focused review and analysis. Dr Lloyd examined scientific papers published between 2002 and 2020 and found that hit frequency was closely linked to assay quality, as measured by the Z'-factor.

Dr Lloyd found that a Z'-factor of 0.65 had an average hit rate of 0.22% whereas a Z'-factor of 0.8 had an average hit rate of 0.83%, clearly demonstrating the significance of an optimised assay.

"These findings underline how important it is to make sure your assay is the best possible quality it can be," said Dr Lloyd. "A high Z' factor, indicative of high-quality lab procedures, enables more hits to be found and ultimately should increase the chances of new treatments being developed.

"Some studies are currently using assays that are not very good in terms of the Z'-factor. It was thought that 0.5 was acceptable but this review shows a level between 0.75 and 0.8 is the minimum that should be aimed for.

He added: "I suspect some researchers don't realise there is such a pronounced effect, which is why they settle for assay with a Z' of 0.7. But in the future, people in industry will need to be mindful of the results of my analysis when they are



To arrange interviews with Dr Lloyd, please contact Vittoria D'Alessio in the University of Bath press office via or call 01225-386319.

The University of Bath

The University of Bath is one of the UK's leading universities both in terms of research and our reputation for excellence in teaching, learning and graduate prospects.

The University is rated Gold in the Teaching Excellence Framework (TEF), the Government's assessment of teaching quality in universities, meaning its teaching is of the highest quality in the UK. In the Research Excellence Framework (REF) 2014 research assessment 87 per cent of our research was defined as 'world-leading' or 'internationally excellent'. From developing fuel-efficient cars of the future, to identifying infectious diseases more quickly, or working to improve the lives of female farmers in West Africa, research from Bath is making a difference around the world.

Find out more:

Well established as a nurturing environment for enterprising minds, Bath is ranked highly in all national league tables. We are ranked 6th in the UK by The Guardian University Guide 2020, 5th for graduate employment in The Times & Sunday Times Good University Guide 2019, and 9th out of 131 UK universities in the Complete University Guide 2021.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.