Abstract14C‐Carbonyl carbofuran toxicity, metabolism and pharmacokinetics in male Sprague‐Dawley rats were studied after 4.1 μm (50 min, 0.2 and 1.2 μg/L) and 1.5 μm (70 min, 0.2 μg/L) aerodynamic diameter monodisperse aerosol exposures. Regional carbofuran deposition for each particle size was similar to human and rodent models for insoluble aerosols. Total carbofuran deposition was greater than expected in the rodent model but similar to that in human models.3‐Hydroxycarbofuran/carbofuran ratios in gastrointestinal tract and liver (1.3, 3 × greater after 4.1 μm) provided additional deposition indices. Rapidin vitrosolubility t1/2(17 min) for 4.1 μm particles and minimal differences in plasma carbamate ( total14C/animal) after varied particle size exposure indicated primary clearance by dissolution, irrespective of deposition site. Carbofuran (1.2 μg/L, 4.1μm) inhibited red blood cell acetylcholinesterase (55 at 10 min postexposure with recovery by 2 h). Eight‐hour14C metabolic fate in14CO2(31–38), urine (9–12), feces (2–5.5) and carcass (44–58) were similar for each particle size. Carbamate pharmacokinetics measured for 2 h postexposure to 4.1 μm particles described monoexponential elimination. Plasma half‐lives for carbofuran (36 min) and 3‐hydroxycarbofuran (62 min) were similar to those previously determined
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