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Percutaneous Absorption
of Neat and Water Solutions of 2-Butoxyethanol in Man
S. Kezic, Coronel Institute of Occupational and Environmental Health,
Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
(Corresponding Author)
N. Mohammadi, Coronel Institute of Occupational and Environmental Health,
Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
I. Jakasa, Coronel Institute of Occupational and Environmental Health,
Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
J. Kruse, Coronel Institute of Occupational and Environmental Health,
Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
A.C. Monster, Coronel Institute of Occupational and Environmental Health,
Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
M. Verberk, Coronel Institute of Occupational and Environmental Health,
Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
Aims
To determine percutaneous absorption of 2-butoxyethanol (BE) dermally
applied as a neat liquid and in 50 and 90 % solutions.
Methods
Six male volunteers were dermally exposed for 4 hr on the volar forearm
over an area of 40 cm ² . An inhalation exposure with a known input
rate served as a reference. Dermal absorption was assessed for each individual
from the concentration courses of BE in blood and butoxyacetic acid in
urine, measured after both inhalation and dermal exposure. The Medical
Ethics Committee of the Academic Medical Centre, University of Amsterdam
approved the experimental protocol. Each subject signed an informed consent
form.
Results
The amount of BE that was absorbed after skin exposure to 50 and 90 %
BE was one order of magnitude higher than that of neat BE. The average
absorption rate of 50 % BE amounted to 0.8 mg/cm ² /hr.
Inter-individual differences in dermal absorption rates of 50 % BE were
moderate, the coefficient of variation (CV) amounted to 30 %. This was
significantly lower than the variation previously reported for neat BE
(Johanson et al 1988).
Conclusions
Dermal uptake of BE increases in the presence of water. This has already
been reported in vivo in guinea pigs (Johanson et al 1988) and in vitro
studies with human skin, however this is the first time that it has been
shown also in humans in vivo. These findings should therefore be considered
in the health risk assessment of occupational dermal exposure to BE where
water-based products containing glycol ethers are used. Comparing the
dermal uptake with the respiratory uptake at the occupational exposure
limit (OEL, currently 100 mg/m ³ ), BE showed substantial skin absorption.
Assuming 60 min skin contact of both hands (skin area of about 1000 cm
² ) with 50 % BE, dermal uptake would equal the pulmonary uptake of
the 8-hr occupational exposure. Therefore, in monitoring exposure at the
work place, biological monitoring (BM) is to be preferred over environmental
monitoring. For the purpose of BM, both BE in blood or BAA in urine can
be used.
References
Johanson G, Boman A. (1988) Influence of water on the percutaneous absorption
of 2-butoxyethanol in guinea pigs, Scand J Work Environ Health. 14:95-100.
Johanson G, Boman A. (1988) Percutaneous absorption of 2-butoxyethanol
in human man, Scand J Work Environ Health. 14:101-109.
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