Biomarkers for monitoring profluthrin exposure: Urinary excretion kinetics of profluthrin metabolites in rats

Recently, a pyrethroid profluthrin [(2,3,5,6-tetrafluoro-4-methylphenyl)methyl 2,2-dimethyl-3-(prop-1-enyl)cyclopropane-1-carboxylate] is widely used as mothproof repellents in indoors. The urinary excretion kinetics of its metabolites was examined in rats to search for urinary metabolites suitable as biomarkers of profluthrin exposure in the general population. A single dose (26-400 mg/kg body weight) of profluthrin was administered intraperitoneally to the rats, and then their urine was collected periodically. Four major profluthrin metabolites, 4-methyl-2,3,5,6-tetrafluorobenzyl alcohol (CH3-FB-Al), 4-hydroxymethyl-2,3,5,6-tetrafluorobenzyl alcohol, 4-methyl-2,3,5,6-tetrafluorobenzoic acid and 2,2-dimethyl-3-(1-propenyl)-cyclopropanecarboxylic acid (MCA) were determined in the urine samples by gas chromatography/mass spectrometry. The kinetic evaluation for each metabolite was achieved by moment analysis of the urinary excretion rate versus time curve. The urinary excretion amounts of the three metabolites, expect for MCA, were estimated to be proportional to the amounts of absorbed profluthrin over a wide exposure range. Urinary CH3-FB-Al was considered to be an optimal biomarker for monitoring of profluthrin.