Scientific, ethical and legal aspects of the acceptance of in vitro methods in regulatory toxicology

Society demands greater safety in the manufacture, distribution and use of chemicals and greater protection of the environment. At the same time currently used, animal based, methods for the identification of toxic chemicals and estimation of risk are often considered scientifically and ethically inadequate. This problem may be, at least in part, solved by the introduction of in vitro methods in regulatory toxicology (Balls et al. 1991). In vitro methods provide means for the development of test procedures that employ human cells and tissues, that make mechanism based risk estimations readily available and that reduces animal strain and suffering. However, the reliability and relevance of such new procedures have to be established through validation studies before they can be accepted.