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Toxicological information

Basic toxicokinetics

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Administrative data

Endpoint:
basic toxicokinetics in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
not reported
Reliability:
1 (reliable without restriction)
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
publication
Title:
Effects of Subchronically Inhaled Carbon Black in Three Species. I. Retention Kinetics, Lung inflammation, and Histopathology
Author:
Elder A, Gelein R, Finkelstein JN, Driscoll KE, Harkema J, Oberdörster G
Year:
2005
Bibliographic source:
Toxicological Sciences 88(2), 614-629

Materials and methods

Objective of study:
other: retention kinetics of carbon black particles in the lung of rats, mice and hamsters
Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
For detailed study description see section "Repeated dose toxicity, inhalation"
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Printex 90 (High surface carbon black), Sterling V (low surface carbon black)
Radiolabelling:
no

Test animals

Species:
other: rat, mouse, hamster
Strain:
other: F344, B6C3F1, F1B Golden Syrian
Sex:
female

Administration / exposure

Route of administration:
inhalation: aerosol
Duration and frequency of treatment / exposure:
13 weeks, 6 hours per day, 5 days per week
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 1, 7 or 50 mg/m3 (High surface carbon black, Printex 90);
50 mg/m3 (Low surface carbon black, Sterling V, only rats)
No. of animals per sex per dose:
6 females / group
Control animals:
yes, sham-exposed
Details on dosing and sampling:
Measurements were performed immediately after exposure and 3 and 11 months post-exposure; retention was also evaluated after 5 weeks of exposure
Statistics:
Results were analysed for statistically significant differences by two-way analysis of variance (ANOVA) with appropriate data transforms followed by Tukey t-tests uing SigmaStat (SPSS Science, Chicago, IL). The two factors for the ANOVAs were exposure dose and time. Data were appropriately transformed (e.g., base 10 logarithm, natural logarithm) if an analysis of residuals suggested deviations from the asumptions of normality and equal variance. Comparisons were considered statistically significant when p<= 0.05

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on excretion:
Particle retention half times for rats, mice, and hamsters following 13 weeks of exposure to carbon black:
HSCb, 1 mg/m3 - rat: 64 days, mice: 133 days, hamsters: 42 days
HSCb, 7 mg/m3 - rat: 115 days, mice: 343 days, hamsters: 53 days
HSCb, 50 mg/m3 - rat: no significant clearance, mice: 322 days, hamsters: 309 days
LSCb, 50 mg/m3 - rat: 249, mice: not tested, hamsters: not tested
Toxicokinetic parametersopen allclose all
Test no.:
#1
Toxicokinetic parameters:
half-life 1st: 1 mg/m3 (high surface area CB): 64 days (rat, later corrected to 107 days, see Pauluhn 2010); 133 days (mouse); 42 days (hamster)
Test no.:
#2
Toxicokinetic parameters:
half-life 1st: 7 mg/m3 high surface CB: 115 days (rat), 343 days (mouse), 53 days (hamster)
Test no.:
#3
Toxicokinetic parameters:
half-life 1st: 50 mg/m3 high surface CB: no significant clearance (rat), 322 days (mouse), 309 days (hamsters)
Test no.:
#4
Toxicokinetic parameters:
half-life 1st: 50 mg/m3 Low surface CB: 249 days (rat), mouse and hamster not tested

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): other: only very small quantities of BaP and other PAH on carbon blacks are bioavailable
only very small quantities of BaP and other PAH on carbon blacks are bioavailable
Executive summary:

Prolonged retention of carbon black particles in the lung was found in rats and mice exposed for 13 weeks to 7 and 50 mg/m3, and in hamsters exposed for 13 weeks to 50 mg/m3. These data show that hamsters have the most efficient clearance mechanism. Low-surface carbon black (50 mg/m3) was more efficiently cleared from the lungs than was 50 mg/m3 high-surface carbon black.