Registration Dossier
Registration Dossier
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EC number: 295-765-2 | CAS number: 92128-68-2
Basic toxicokinetics
Administrative data
- Endpoint:
- basic toxicokinetics
- Type of information:
- migrated information: read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Non-GLP, non-guideline, data modelling study, published in peer reviewed literature, fully adequate for assessment.
Data source
Reference
- Reference Type:
- publication
- Title:
- Unnamed
- Year:
- 2 001
Materials and methods
- Objective of study:
- toxicokinetics
Test guideline
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- A physiological toxicokinetic model was developed on the basis of previously reported models.
- GLP compliance:
- not specified
Test material
- Reference substance name:
- Isoprene
- EC Number:
- 201-143-3
- EC Name:
- Isoprene
- Cas Number:
- 78-79-5
- Molecular formula:
- C5H8
- IUPAC Name:
- isoprene
- Reference substance name:
- 2-methyl-1,3-butadiene
- IUPAC Name:
- 2-methyl-1,3-butadiene
Constituent 1
Constituent 2
Test animals
- Species:
- other: human, rat, mouse
Administration / exposure
- Route of administration:
- inhalation
- Vehicle:
- not specified
Results and discussion
Toxicokinetic / pharmacokinetic studies
- Details on absorption:
- Atmospheric concentration-time curves fitted to data from rats and mice exposed by inhalation to isoprene demonstrated that metabolism is saturable.
- Details on excretion:
- The model predicts that in rats exposed by inhalation to 8 ppm isoprene, approximately 21% of inhaled isoprene is metabolised.
Toxicokinetic parametersopen allclose all
- Toxicokinetic parameters:
- other: the rate of endogenous production of isoprene in a 70 kg man was estimated to be 23.8 µmol/h (0.34 µmol/h/kg); approximately 90% is metabolised, the remaining 10% is exhaled unchanged
- Toxicokinetic parameters:
- other: the model predicts that endogenous production of isoprene will result in blood concentrations of 9.5 nmol/L in humans
- Toxicokinetic parameters:
- other: rats: Km=180ppm
- Toxicokinetic parameters:
- other: mice: Km=360ppm
Applicant's summary and conclusion
- Conclusions:
- Interpretation of results (migrated information): other: For man, the estimated area under the blood concentration versus time curve (AUC) following exposure by inhalation to 10 ppm isoprene for 8h is 4-fold higher than the 24 h AUC resulting from exposure to endogenous isoprene.
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