Kinetics of 3-(4-methylbenzylidene)camphor in rats and humans after dermal application
- Institute of Toxicology, University of Wuerzburg, Versbacherstrasse 9, 97078 Wuerzburg (Germany)
- Institute of Toxicology, Merck KGaA, 64271 Darmstadt (Germany)
The toxicokinetics of 4-MBC after dermal administration were investigated in human subjects and in rats. Humans (3 male and 3 female subjects) were exposed to 4-MBC by topical application of a commercial sunscreen formulation containing 4% 4-MBC (w/w), covering 90% of the body surface and resulting in a mean dermal 4-MBC dose of 22 mg/kg bw. In rats, dermal 4-MBC doses of 400 and 2000 mg/kg bw were applied in a formulation using an occlusive patch for 24 h. Concentrations of 4-MBC and its metabolites were monitored over 96 h in plasma (rats and humans) and urine (humans). In human subjects, plasma levels of 4-MBC peaked at 200 pmol/ml in males and 100 pmol/ml in females 6 h after application and then decreased to reach the limit of detection after 24 h (females), respectively, 36 h (males). After dermal application of 4-MBC, peak plasma concentrations of 3-(4-carboxybenzylidene)-6-hydroxycamphor were 50-80 pmol/ml at 12 h and of 3-(4-carboxybenzylidene)camphor were 100-200 pmol/ml at 24 h. In male and female rats, peak plasma levels of 4-MBC were 200 (dose of 400 mg/kg bw) and 1 200 pmol/ml (dose of 2000 mg/kg bw). These levels remained constant for up to 24-48 h after dermal application. Peak plasma concentrations of 3-(4-carboxybenzylidene)-6-hydroxycamphor were 18,000 pmol/ml (males) and of 3-(4-carboxybenzylidene)camphor were 55,000 pmol/ml (females) between 48 and 72 h after application of the high dose of 4-MBC. In human subjects, only a small percentage of the dermally applied dose of 4-MBC was recovered in the form of metabolites in urine, partly as glucuronides. The obtained results suggest a more intensive biotransformation of 4-MBC in rats as compared to humans after dermal application and a poor absorption of 4-MBC through human skin.
- OSTI ID:
- 20850455
- Journal Information:
- Toxicology and Applied Pharmacology, Vol. 216, Issue 2; Other Information: DOI: 10.1016/j.taap.2006.05.011; PII: S0041-008X(06)00190-6; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0041-008X
- Country of Publication:
- United States
- Language:
- English
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