Issue 23 — November 2000

Issue 23
Category		Title		Author
Congress Report		Measurements of the Penetration Behavior of Various Cosmetic Raw Materials Using the Porcine Skin Model		Susann Richert

Figure: Installation of a penetration experiment with porcine skin in diffusion chambers

The measurement and prediction of percutaneous absorption has been carried out routinely in numerous laboratories for more than thirty years. Since summer 1999, an internationally validated and accepted animal-free test method (SCCNFP/0119/99 and SCCNFP/088/98) has been available, where the porcine skin model is preferred to the examination of excised human skin. In vitro methods offer the advantage of being simpler, faster, more reproducible and economical than corresponding in vivo investigations. In the new guidelines, the examination of the percutaneous absorption/penetration plays a decisive role in the safety evaluation of cosmetic raw materials and end products. This means that animal tests with systemic applications are only required for substances which penetrate the skin. Further-reaching tests, such as epicutaneous tests to examine the compatibility, remain untouched by this.

The penetration behaviour of various cosmetic raw materials may be analyzed with the porcine skin model. The measurement of the test substance from the departing material to the washin water and the permeation liquid to determine the residual content in the skin results in a total balance which allows a surveillance of the course of the experiment. For the carrying out of the penetration experiment it is indispensible to compile a mass balance. Here it is important to adapt the method of analysis to the raw material selected, in order to obtain sufficient recovery rates. According to the COLIPA Guideline they have to amount to 100 percent ± 15 percent. PEG 22/Dodecyl Glycol Copolymer, cyclo paraffin oil and all-trans retinol, the substances tested by us, did not penetrate from the selected bases into the skin at all or did so only in traces.


Figure: Test sequence - examination of percutaneous permeation

Author

Dr. rer. nat. Susann Richert



Studied Food Chemistry, majoring in Cosmetic Chemistry. From 1992-1995: scientific assistant at the PGU Research Institute of Beiersdorf AG, Hamburg. From 1996-1997 scientific assistant at the NIH, NHLBI, Laboratory of Biochemistry, U.S.A.. Since April 1997 head of Toxicological Research at the Institut Dr. Schrader Creachem. Her field of activities includes the development and validation of toxicological analyses as well as the planning and realization of toxicological studies on the safety evaluation of cosmetics and pharmaceutical topical preparations.

In November 1999, the first forum of the leading research association for the cosmetic industry, FKI, took place at the Institute Dr. Schrader in Holzminden, Germany. The Institute Dr. Schrader Creachem is the research location of the FKI. Dr. Susann Richert reported on her current project of the association.