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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Toxicological information

Basic toxicokinetics

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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:
2001

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

Constituent 1
Chemical structure
Reference substance name:
Isoprene
EC Number:
201-143-3
EC Name:
Isoprene
Cas Number:
78-79-5
Molecular formula:
C5H8
IUPAC Name:
isoprene
Constituent 2
Reference substance name:
2-methyl-1,3-butadiene
IUPAC Name:
2-methyl-1,3-butadiene

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.