Registration Dossier

Diss Factsheets

Administrative data

Endpoint:
basic toxicokinetics in vivo
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
documentation insufficient for assessment

Data source

Reference
Reference Type:
other company data
Title:
Unnamed
Year:
1998
Report date:
1998

Materials and methods

Objective of study:
absorption
metabolism
Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
The objective of the study was to determine if the test substance undergoes absorption and metabolism after inhalation exposure in rats.
GLP compliance:
not specified

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male

Administration / exposure

Route of administration:
inhalation
Doses / concentrationsopen allclose all
Dose / conc.:
100 ppm
Dose / conc.:
500 ppm
Dose / conc.:
2 000 ppm
Dose / conc.:
5 000 ppm
Control animals:
yes

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on absorption:
Tissue-to-air partition coefficients were collectively negative, and the data suggest that very little uptake of test substance occurs into tissues. According to the method used, it is likely that the blood-to-air partition of <0.5 would be observed. Thus only a small amount of the test substance would be inhaled, and after the end of exposure, the test substance that remains in the blood would be rapidly exhaled. This observation was supported by the preliminary gas uptake data.
Comparison of 2000 ppm exposure and control exposure indicated that the test substance does not undergo significant uptake and metabolism. At 100 ppm, an initial uptake of test substance is apparent in the first 75 minutes, but chamber concentration levels off indicating no further metabolism.

Applicant's summary and conclusion

Conclusions:
Only a small amount of the test substance would be inhaled, and after the end of exposure, the test substance that remains in the blood would be rapidly exhaled.
Executive summary:

The objective of the study was to determine if the test substance undergoes absorption and metabolism after inhalation exposure in rats. Rats were exposed to concentrations of 0, 100, 500, 2000, or 5000 ppm via inhalation. Tissue-to-air partition coefficients were collectively negative, and the data suggest that very little uptake of test substance occurs into tissues. According to the method used, it is likely that the blood-to-air partition of <0.5 would be observed. Thus only a small amount of the test substance would be inhaled, and after the end of exposure, the test substance that remains in the blood would be rapidly exhaled. This observation was supported by the preliminary gas uptake data. Comparison of 2000 ppm exposure and control exposure indicated that the test substance does not undergo significant uptake and metabolism. At 100 ppm, an initial uptake of test substance is apparent in the first 75 minutes, but chamber concentration levels off indicating no further metabolism.