A Comparative Study on the Skin Penetration of Pure Tryptanthrin and Tryptanthrin in Isatis tinctoria Extract by Dermal Microdialysis Coupled with Isotope Dilution ESI-LC-MS - Oberthür, Christine; Heinemann, Christian; Elsner, Peter; Benfeldt, Eva; Hamburger, Matthias (Planta Medica, 2003)