Fate of inhaled azodicarbonamide in rats
Azodicarbonamide (ADA) is widely used as a blowing agent in the manufacture of expanded foam plastics, as an aging and bleaching agent in flour, and as a bread dough conditioner. Human exposures have been reported during manufacture as well as during use. Groups of male F344/N rats were administered ADA by gavage, by intratracheal instillation, and by inhalation exposure to determine the disposition and modes of excretion of ADA and its metabolites. At 72 hr following gavage, 30% of the administered ADA was absorbed whereas following intratracheal instillation, absorption was 90%. Comparison between groups of rats exposed by inhalation to ADA to achieve body burdens of 24 or 1230 micrograms showed no significant differences in modes or rates of excretion of (/sup 14/C)ADA equivalents. ADA was readily converted to biurea under physiological conditions and biurea was the only /sup 14/C-labeled compound present in excreta. (/sup 14/C)ADA equivalents were present in all examined tissues immediately after inhalation exposure, and clearance half-times on the order of 1 day were evident for all tissues investigated. Storage depots for (/sup 14/C)ADA equivalents were not observed. The rate of buildup of (/sup 14/C)ADA equivalents in blood was linearly related to the lung content as measured from rats withdrawn at selected times during a 6-hr inhalation exposure at an aerosol concentration of 25 micrograms ADA/liter. In a study extending 102 days after exposure, retention of (/sup 14/C)ADA equivalents in tissues was described by a two-component negative exponential function. The results from this study indicate that upon inhalation, ADA is rapidly converted to biurea and that biurea is then eliminated rapidly from all tissues with the majority of the elimination via the urine.
- Research Organization:
- Inhalation Toxicology Research Institute, Albuquerque, NM
- OSTI ID:
- 6332563
- Journal Information:
- Fundam. Appl. Toxicol.; (United States), Vol. 3
- Country of Publication:
- United States
- Language:
- English
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METABOLISM
CARBON 14 COMPOUNDS
TISSUE DISTRIBUTION
AEROSOLS
BODY BURDEN
CLEARANCE
INHALATION
INTRATRACHEAL ADMINISTRATION
METABOLITES
RATS
STOMACH
TRACHEA
URINE
ANIMALS
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY
BODY FLUIDS
COLLOIDS
DIGESTIVE SYSTEM
DISPERSIONS
DISTRIBUTION
GASTROINTESTINAL TRACT
INTAKE
LABELLED COMPOUNDS
MAMMALS
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ORGANIC NITROGEN COMPOUNDS
ORGANS
RESPIRATORY SYSTEM
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SOLS
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550201* - Biochemistry- Tracer Techniques