The long path to a medicine

3. Preclinical testing in the living organism

When substances have eventually arrived at the point where they have the potential to become a medicine, these drug candidates are tested for efficacy and safety in preclinical studies. Toxicologists and other specialists analyse them for toxicity to rule out the possibility that they may trigger diseases such as cancer or cause genetic damage. Computer simulations are used for these investigations such as bacteria, cell and tissue cultures or isolated organs. Tests with rats or mice, in relatively rare cases also with non-rodents, are necessary to study interactions of promising substances with cells and organs in the living organism. Tests of this kind are absolutely essential, for example, to determine whether a substance remains in the body long enough to achieve the desired medical effect. Tests with at least two animal species (e.g. rats and dogs) are required by law for clarifying certain issues. All tests are always conducted in accordance with internationally recognized standards.