Application of deuterated compounds for investigations of percutaneous absorption of chemical substances

The percutaneous absorption of the xenoestrogen 2,2-bis-(4-hydroxyphenyl)-p ropane (bisphenol A) 1 has been studied and compared with results on dibenz oyl peroxide 2, a component of drug formulations for topical application. I solated perfused bovine udders from slaughtered cows were employed as model s for human skin. The deuterium labelled compounds 1-d(14) and 2-d(10) were applied to enhance the reliability of GC-MS trace determinations by use of reverse isotope dilution analysis. 1-d(14) was found in perfusate and milk equivalent samples obtained between 60 and 300 min after topical applicati on with maximum concentrations between 120 and 180 min. 1-d(14) was enriche d in the milk samples by a factor of about 300 compared with the perfusate. The results confirm a possible penetration of 1 from the environment throu gh the skin into the capillary system. 2 studied on the same model system p enetrated faster than 1 by a factor of about three.