Evaluating skin tolerability

With the 6th Amendment Directive to the Cosmetics Directive, passed by the European Parliament in 1993, politicians and parliaments called for the adoption of alternative methods not involving animal experiment. In the same year, isolated perfused bovine udder (BUS model, Bovine Udder Skin) was introduced to dermatological research as a natural skin model.1 In the developments leading up to this at the Hanover University of Veterinary Medicine, the methodical focus had been on the viability of the skin after perfusion, while the scientific focus was on the penetration of the pharmaceuticals or dermatological medicaments in question. Among the preconditions of effective penetration, one must evaluate possible skin irritations as a principal concern in relation to cosmetic applications.

Projects of this kind had already been carried out at Henkel in Düsseldorf under Professor Christian Gloxhuber (1920–2016), as forming part of its biological research and product development.2 Together with Professor Manfred Kietzmann of the Institute of Pharmacology, Toxicology and Pharmacy of the Hanover University of Veterinary Medicine, the natural skin model was modified for use in cosmetics and chemistry with a view to testing for tolerability and penetration. Since 1994, relevant products, constituents and effective ingredients which come into contact with the skin accidentally or in the nature of the application involved have been investigated without any animal involvement. A major issue, dealt with in numerous publications, was that of natural vitamin E in skin care, together with the penetration properties of various cosmetic formulations.3, 4, 5, 6