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Cell tests can replace testing for phototoxicity of chemicals in animals

05/2000, 24.02.2000

A test method developed by the Federal Institute for Health Protection of Consumers and Veterinary Medicine (BgVV) has been officially accepted by the European Union.

On 4 February 2000 the competent authorities of the European Union officially accepted a method involving no animal experiments for testing the phototoxicity of chemical substances. This in vitro phototoxicity test was developed under the aegis of the Centre for Documentation and Evaluation of Alternatives to Animal Experiments (ZEBET). Thus, for the first time there is a validated method officially recognised within the European Union for phototoxicity testing.

In tests on phototoxicity it was examined what health effects chemical substances have when exposed to light. A chemical substance is described as phototoxic when following the application or ingestion of the substances there is reddening, swelling or other reactions or damage to the skin or other organs which are exposed to light and sunlight.

Phototoxicity testing is necessary for medicinal products and for substances used in cosmetics as sun protection filters. So far manufacturers have also had to provide details of the phototoxicity of the substance used in the field of cosmetics but no test method was stipulated. In practice, phototoxicity testing normally involved animal experiments. Mice, rats, guinea pigs or rabbits were treated with test substances and then the shaved skin was exposed to UV light.

In the BgVV method involving no animal experiments, cells of mice or of human skin are treated during cultivation in the incubator with test substances and exposed to UV light. Surprisingly, the BgVV cell culture test predicts the reactions in humans far better than the animal experiments. Hence, the new cell culture test is far better suited for safety toxicological risk assessment in man than the animal experiment. Furthermore, it is cheaper and can be conducted far more quickly. Around the world the cosmetics industry is already using the new test to examine the safety of UV filter substances in sun protection products.

Since 1992 ZEBET within BgVV has developed this in vitro test for testing the phototoxic properties of new chemicals in close co-operation with the major companies in the European cosmetics industry or the Association of Cosmetics Manufacturers (COLIPA) in Brussels. Despite the good correlation of the results produced by the cell culture test in comparison with the effects observed in man, the new test had to be tested in a large number of laboratories of the cosmetics industry in Europe, Japan and the USA with regard to its reliability. The test had to be conducted under blind conditions with coded test substances. This type of experimental examination of the reliability of a new test method for consumer protection is called validation. It is prescribed internationally. Only when validation has been completed, will a new test method be internationally recognised by the competent authorities for consumer protection. The results of this extensive experimental validation have now been positively evaluated by the competent authority in Brussels, the Directorate General for the Environment, Reactor Safety and Chemicals (DG E) and thus officially accepted.

Authorised safety toxicological test methods are listed in Annex V of the Council Directive relating to the classification, packaging and labelling of dangerous substances (Council Directive 67/548/EEC). On 4 February 2000 the representatives of the 15 EU Member States approved the 27^th amendment of the Directive. As a consequence of this amendment, so-called alternative methods involving no animal experiments were included for the first time in Annex V of the Dangerous Substances Directive. This involves the in vitro phototoxicity test of BgVV and two methods for testing chemical substances for their corrosive effect on the skin in which artificial human skin or rat skin is used. Based on EU Directive 86/609/EEC concerning the protection of experimental animals, no animal experiments may be conducted any more in the field of phototoxicity testing of substances for cosmetics and medicinal products and testing of the corrosive effect on the skin of chemicals after formal confirmation by the European Parliament and six months after the publication of this amendment in the Official Journal of the EU in the EU Member States. If the in vitro test for the corrosive effect is negative, then other animal experiments are necessary to test the irritating effect of the chemicals.

From the scientific angle the cell culture method indicates a new beginning since this new method is able, beyond the customary animal experiments, to predict toxic effects in humans with a large degree of reliability. For animal protection and consumer protection in Germany in Europe but also for BgVV this success is an encouraging breakthrough. The Institute was able for the first time using the example of phototoxicity to demonstrate that it is possible with the help of experimentally validated cell culture methods to correctly estimate the risk for man and in this way to replace inhumane animal experiments.

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