TISSUE CONCENTRATIONS OF METHYL ISOBUTYL KETONE, METHYL N-BUTYL KETONE AND THEIR METABOLITES AFTER ORAL OR INHALATION EXPOSURE

Quantitative relationships between plasma, liver and lung methyl isobu tyl ketone (MiBK) and methyl n-butyl ketone (MnBK) concentrations afte r oral or inhalation exposure were established. Their respective metab olites (4-methyl-2-pentanol, 4-hydroxy-methyl isobutyl ketone, 2-hexan ol, and 2,5-hexanedione) were also quantified. Male Sprague-Dawley rat s were exposed for 3 days to MiBK or MnBK vapors (4 h/day) or treated orally for 3 days with a MiBK-or MnBK-corn. oil solution. Both ketones and their respective metabolites in plasma or tissue concentrations w ere determined by gas chromatography. MiBK and MnBK plasma and tissue concentrations increased in a dose-related manner with the administere d dose irrespective of the route of administration. Metabolite concent rations, however, were influenced by the route of administration.