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On the average, it takes twelve years from the discovery of a potential molecule till its launch. The whole process costs about one billion Euros. This figure  includes unsuccessful attempts which are found to be unsuitable and eliminated during the development process.

Evidence of safety

Is the potential active substance harmless? Before a potential active substance can be tested on human being, it needs to go through preclinical trials. Here, the substance is tested for toxicity or possible injury for the human body. These tests are sometimes performed on cell cultures (‘in vitro’); at other times, however, tests on an entire organism are indispensable (‘in vivo’).

The preclinical tests on toxicity include tests on acute toxicity, sub-chronic toxicity, chronic toxicity, reproductive toxicity, carcinogenicity and on local tolerance.

The tests on acute toxicity provide a first impression on whether or not a substance is poisonous. In these tests, the substance is administered to two different species. This way, the range between the effective and the toxic dose can be determined. In the tests on sub-chronic toxicity, the substance is administered repeatedly; hereby, new insights on possible side effects in long-term administration can be gained. During the tests on chronic toxicity, the substance is repeatedly administered using the planned application method. By using the results of this long-term administration, the researchers can determine the lowest dose (as planned for humans) and highest (toxic) dose.

Reproductive toxicology examines the effect of the drug on procreation. This includes such things as tests on teratogenicity (test on malformation of embryos), tests on fertility and on perinatal toxicity, which deals with addiction after birth, for example. Further tests analyse carcinogenicity, that is the possible increase of tumour development, as well as local tolerance, which is intended to eliminate irritative and allergenic potential.

last update:  11 Jan 2012