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Studies on the rate of uptake of isobutanal through the intact skin are not available; dermal uptake through the vulnerated skin after prolonged exposure and occlusive conditions has been shown in the course of an old acute dermal toxicity study. (Union Carbide, 1952; cited in OECD SIDS 2004)

Isobutanal, like other simple aliphatic aldehydes, is subject to oxidation in animals by ubiquitous aldehyde dehydrogenase enzymes. The oxidation product, isobutyric acid, is rapidly metabolized to CO2 through conversion to the isobutyral coenzyme A complex and subsequent oxidation by the malate-pyruvate and oxaloacetic-phosphoenol pyruvate pathways (DiVincenzo and Hamilton, 1979; cited in OECD SIDS 2004).

In in vitro studies, isobutyraldehyde was shown to undergo oxidative deformylation catalyzed by rabbit liver cytochrome P450 enzymes yielding propylene and formic acid (Roberts et al., 1991, Proc. Natl. Acad. Sci. 88, 8963 - 8966); cited in NTP TR 472, 1999). Isobutyraldehyde showed little oxidation by rat liver mitochondria (Smith and Packer, 1972, Arch.Biochem.Biophys. 148.270 -276; cited in NTP TR 472, 1999).