Testing Drugs In Vitro
Testing by nuclear magnetic resonance spectroscopy is an innovation used to test whether compounds bind to target proteins. Antibacterial drugs are tested in vitro by studying their effect on the growth of a testing range of bacterial strains. There are many different ways in which in vitro tests can be carried out, involving studies on isolated enzymes, whole cells, tissue preparations and organs. The stronger the affinity of the test compound, the more effectively it will compete for binding sites and the less radioactivity will be measured in the experiment for the cells or tissue. The measure of how effectively a drug inhibits an enzyme is known as the IC50 value, which represents the concentration of inhibitor that is required to reduce enzyme activity by 50%. Cells can be studied more easily and there are no complications arising in the drug having to cross barriers such as the gut wall in order to reach its target.