Dermal absorption of toluene from enamel paint in F344 rats.
Kania-MR; Woodstock-AD; Thrall-KD
Toxicologist 2003 Mar; 72(S-1):381-382
Toluene is a component of many paint products and there is potential for both occupational and non-occupational dermal exposure to toluene in various matrices. To understand the significance of these exposures, the dermal bioavailability of toluene was assessed in F344 male rats using a combination of real-time exhaled breath analysis and physiologically based pharmacokinetic (PBPK) modeling. Animals were exposed to toluene present in a commercial enamel paint using a 1.7cm diameter occluded glass patch system attached co a clipper-shaved area on the back of the rat. Immediately following exposure, individual animals were placed in glass off-gassing chambers and exhaled breath was monitored as chamber concentration using an ion trap mass spectrometer (MS/MS). The exhaled breath profiles from treated animals clearly demonstrated the rapid absorption of toluene. Peak chamber concentrations, representing exhaled breath, were observed within 1 hr from the start of exposure. The PBPK model describing the exposure and offgassing chamber was used to model the exhaled breath data. A dermal permeability coefficient (Kp) of 0.073 cm/hr was found to describe each set of exhaled breath data. In comparison, the Kp value determined for enamel paint was identical co the Kp value for aqueous toluene (0.074 cm/hr) although toluene concentrations differed significantly (25 mg/ml versus 0.5 mg/ml). To evaluate the impact of paint constituents on the dermal bioavailability, additions dermal studies were conducted using reformulated enamel paint with the titanium dioxide and xylene co-solvent replaced by toulene. PBPK model simulation of the exhaled breath data from these exposures required a Kp value roughly half the value from the intact paint (0.032 cm/hr) althought the toulene concentration was more than 12 times greater. These data suggest that permeability of toluene is influenced by the exposure concentration and less so by the exposure matrix.
Aqueous-solutions; Toluenes; Paints; Laboratory-animals; Animals; Animal-studies; Occupational-dermatitis; Dermatitis; Occupational-exposure; Exposure-levels; Solvents; Skin-exposure
1330-20-7; 13463-67-7; 108-88-3
Disease and Injury: Allergic and Irritant Dermatitis
The Toxicologist. Society of Toxicology 42nd Annual Meeting and ToxExpo, Cutting-Edge Science, Networking, New Perspectives, March 9-13, 2003, Salt Lake City, Utah
Battelle Memorial Institute, Richland, Washington