Disposition of 2,4-dichlorophenoxyacetic acid dimethylamine by Fischer 344 rats dosed orally and dermally
- Environmental Health Centre, Ottawa, Ontario (Canada)
The dimethylamine salt of 14C-ring-labeled 2,4-D was administered to Fischer 344 rats orally (1 and 0.4 mg/kg body weight) and dermally (10 mg/kg body weight). Absorption, distribution, and elimination were determined from 14C-labeled 2,4-D in blood, tissues, and excreta. Quantitatively, most of the orally administered dose (94-96%) became systemically available within 6 h. Following dermal administration 10% of the dose became systemically available over 72 h. However, peak concentrations in blood and kidneys were achieved within 30 min of dosing by either route. By 1.5 h after dosing, 2,4-D concentrations in blood, muscle, liver, and kidneys had decreased in both the orally dosed and dermally dosed animals. Between 2 and 8 h, the blood, muscle, liver and kidney concentrations in dermally dosed animals maintained a plateau while urinary excretion increased, presumably due to continued absorption of 2,4-D from the skin. The concentrations in orally dosed animals continued to decrease. Following 7 h of dermal exposure, skin cleansing removed about 63% of the applied dose; about 17% of the applied dose remained at the site of dermal dosing. At 8 h, 2,4-D concentrations in blood, muscle, liver, and kidneys of dermally dosed animals began to decrease, most likely a result of the removal of the reservoir on the skin. However, 2,4-D continued to be absorbed from skin site, resulting in a slower decline of the 2,4-D concentrations in these tissues over remainder of the 72-h study period. By comparison, in animals that had been orally dosed, the absorbed dose was almost completely excreted within 24 h.
- OSTI ID:
- 5159810
- Journal Information:
- Journal of Toxicology and Environmental Health; (USA), Vol. 28:2; ISSN 0098-4108
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HERBICIDES
METABOLISM
CARBON 14 COMPOUNDS
ORAL ADMINISTRATION
RATS
SKIN ABSORPTION
TISSUE DISTRIBUTION
TRACER TECHNIQUES
ABSORPTION
ANIMALS
DISTRIBUTION
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
PESTICIDES
RODENTS
UPTAKE
VERTEBRATES
550501* - Metabolism- Tracer Techniques