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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
19 November 2008 - 16 December 2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report date:
2009

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Details on test material:
-Physical state: tan coloured solid
-storage condition of test material: room temperature in the dark

In vivo test system

Test animals

Species:
mouse
Strain:
other: Other: CBAICa (CBAICaOIaHsd) strain
Sex:
female

Study design: in vivo (LLNA)

Vehicle:
dimethyl sulphoxide
Concentration:
50%, 25% or 10% wlw in dimethyl sulphoxide
No. of animals per dose:
5/dose
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
mercaptobenzothiazole (CAS No 149-30-4)
Statistics:
Data was processed to give group mean values for disintegrations per minute and standard deviations where appropriate. Individual and group mean disintegrations per minute values were assessed for dose response relationships by analysis of homogeneity of variance followed by one way analysis of variance (ANOVA). In the event of a significant result from the ANOVA, pairwise comparisons were performed between control and treated groups. For homogenous datasets Dunnett's Multiple Comparison test was used and for non-homogenous datasets Dunnett's T3 Multiple Comparison Method was used.

Probability values (p) are presented as follows:

P<0.001 ***

P<0.01 **

P<0.05 *

P0.05 (not significant)


Results and discussion

In vivo (LLNA)

Resultsopen allclose all
Key result
Parameter:
SI
Value:
2.98
Test group / Remarks:
10%
Key result
Parameter:
SI
Value:
2.53
Test group / Remarks:
25%
Key result
Parameter:
SI
Value:
3.09
Test group / Remarks:
50%

Any other information on results incl. tables

The Stimulation Index expressed as the mean radioactive incorporation for each treatment group divided by the mean radioactive incorporation of the vehicle control group:

Table 1. Stimulation Index

Concentration (% wlw) in

dimethyl sulphoxide

Stimulation Index

10

2.98

25

2.53

50

3.09

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
The Stimulation Index of the highest dose tested (SI = 3.09 @ 50%) resulted in a negligible exceedance of the recognized threshold for characterizing a test material as a dermal sensitizer. Further, data generated for the middle and lower concentrations (SI's = 2.53 and 2.98 respectively) showed a clear lack of dose response and did not show statistical differences in the mean dpm/animal in comparison with the highest dose. Taking these observations into account, the results of this study do not conclusively support the conclusion that the test substance is a skin sensitizer.
Executive summary:

A study was perfomred to assess the skin sensitization potential of the test material in the CBA/Ca strain mouse following topical application to the dorsal surface of the ear according to OECD Guideline No. 429 "Skin Sensitization: Local Lymph Node Assay" (adopted 24 April 2002), Method B42 Skin Sensitization (Local Lymph Node Assay) of Commission Directive 2004/73/EC, and United States Environmental Protection Agency Health Effects Test Guidelines OPPTS 870.2600 Skin Sensitization March, 2003.Following a preliminary screening test in which no clinical signs of toxicity were noted at a concentration of 50% wlw, this concentration was selected as the highest dose investigated in the main test of the Local Lymph Node Assay. Three groups, each of five animals, were treated with 50 pi (25 pi per ear) of the test material as a solution in dimethyl sulphoxide at concentrations of 50%, 25% or 10% wlw. A further group of five animals was treated with dimethyl sulphoxide alone. The Stimulation index of 50% dose group (SI= 3.09) resulted in a negligible exceedance of the recognized threshold for characterizing a test material as a dermal sensitizer. Further, data generated for the middle and lowerconcentrations (SI's = 2.53 and 2.98 respectively) showed a clear lack of dose response and did not show statistical differences in the mean dpm/animal in comparison with the highest dose. Taking these observations into account, the results of this study do not conclusively support the conclusion that the test substance is a skin sensitizer.