Pittermann, W., M. Kietzmann, and B. Jackwerth. The Bovine Udder Skin Model. [Abridged version of an article in "ALTEX" 1995, 12/4, page 196 . Original Title: "Das isoliert perfundierte Rindereuter (Bovine Udder Skin - BUS Model): Ein integriertes in-vitro-Modell zur Untersuchung von Hautpenetration und irritation".]

"Whereas in vivo studies on local compatibility are relatively easy to carry out, there are ethical reasons why questions of transdermal absorption can only be dealt with in vivo under certain conditions and hence on a very limited scale. The search for suitable in vitro models has produced a number of test methods which correspond more or less to in vivo conditions. A model frequently used is the "isolated perfused rabbit's ear". However, the absorption rates can only be conditionally applied to other species. Better possibilities for comparison are afforded by the model of the "isolated perfused pig's ear" of which the transdermal absorption rates of industrial chemicals reliably predict those of the human skin. Since metabolization reactions take place in the skin, they are only detected in living skin, i.e. under in vitro conditions only in perfused skin. With the isolated perfused bovine udder skin (BUS) model, an in vitro method has been developed which enables skin irritation, penetration and absorption to be investigated in one and the same model."