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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
08 March 2006 to 04 April 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and guideline study
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Qualifier:
according to
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
GLP compliance:
yes
Type of study:
mouse local lymphnode assay (LLNA)
Test material information:
Composition 1
Species:
mouse
Strain:
other:
Sex:
female
Details on test animals and environmental conditions:
At the start of the study the mice were in the weight range of 15 to 23 grams and were eight to twelve weeks old. Free access to mains drinking water and food was allowed through out the study. The temperature and relative humidity were set to achieve limits of 19 to 25 C and 30 to 70% respectively. The rate of air exchange was at least 15 changes per hour and the lighting was controlled by a time switch to give 12 hours continuous light and 12 hours of darkness.
Vehicle:
dimethylformamide
Concentration:
test material at concentrations of 10%, 25% or 50% w/w
No. of animals per dose:
Three groups of five animals each were treated at each concentration group and a further group of five animals were treated as a control group with dimethyl formamide alone.
Details on study design:
The preliminary screening test suggested that the test material would not produce systemic toxicity or excessive local irritation at the highest suitable concentration. The mice were treated by daily application of 25 μl of the appropriate concentration of the test material to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3) by using a micropipette whose tip is used to spread the formulation over the dorsal surface of each ear. On Day 6 all mice were injected with 250 ul of a phophate buffered saline solution containing 3H-methyl thymidine (3HTdR ) to the tail vein giving a total of 20 uCi to each mouse. All animals were observed twice daily on Day 1, 2 and 3 and once daily on days 4 ,5, and 6. Any signs of toxicity or ill health were noted. Body weights of each mouse were recorded before dosing and before termination. Five hours after administration of 3HTdR all mice were killed by carbon dioxide asphyxiation and their auricular lymph nodes were excised and a 1 ml of phosphate buffered saline was added to each set of lymph nodes. Preparation of a single cell suspension was completed for the lymph nodes cells for each individual animal following standard procedures. Determination of the 3HTdR incorporation was completed by measuring radioactive disintegration for each animal's lymph node cells by using a beta-scintillation counter.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
Group mean values for disintegration per minute (dpm) and standard deviations where appropriate are completed. Individual and dose mean dpm values were assessed for dose response relationships by analysis of homogenicity of variance followed by one way analysis of variance (ANOVA). If significant results were determined from the ANOVA then 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.
Positive control results:
α-Hexylcinnamaldehyde, Tech, 85% was considered to be a sensitiser under the conditions of the test with SI rates of 5%- 2.5( Negative), at 10% SI- 4.03 (Positive) and 25% a SI of 9.13% (Positive).
Parameter:
SI
Remarks on result:
other: see Remark
Remarks:
Concentration of test material in the vehicle at 10 % resulted in a stimulation index (SI) of 2.67 which is a negative result. Concentration of test material in the vehicle at 25 % resulted in a stimulation index (SI) of 3.90 which is a positive result.Concentration of test material in the vehicle at 50 % resulted in a stimulation index (SI) of 11.58 which is a positive result.
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: see Remark
Remarks:
Concentration of test material in the vehicle at 10 % resulted in a mean disintegration of 2220.74 dpm which is a negative result.Concentration of test material in the vehicle at 25 % resulted in a mean disintegration of 3244.21 dpm which is a positive result. Concentration of test material in the vehicle at 50 % resulted in a mean disintegration of 9629.51 dpm which is a positive result.

Preliminary test.No signs of systemic toxicity wee noted. Fur loss to the back of the ear was noted 1 hr post dosing on day 2 and then remainder of the study. Mild redness to the ears and head were noted day 4 & 5.

Main test: There were no deaths. No signs of systemic toxicity were noted in the test or control animals

during the test. Fur loss to the back of the ear was noted 1 hr post dosing on day 3 and then remainder of the study in all animals at 50 w/w%.

 Concentration (% w/w) in dimethyl formamide  Stimulation Index (SI)  Result
10   2.67

Negative

 25  3.90  Positive
 50  11.58  Positive
 

The LLNA EC3 value for induction (14.0%) was calculated according to Kimber et al 2001 Tox Sci 59(2)198-208.

Interpretation of results:
sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test material was considered to be a sensitiser under the conditions of the test.
Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

A single study has been conducted in accordance with GLP and the OECD 429 guideline. The results of the study indicate that the substance is a moderate skin sensitiser in mice with a measured EC3 value of >10% w/w in dimethylformamide. The LLNA EC3 value for induction (14%) was calculated according to Kimber et al 2001 Tox Sci 59(2)198-208. This is converted to a dose of 3505 µg/cm2 in accordance with ECHA guidance document Chapter R8, in Appendix R.8-10.; this point of departure is considered to be a LOAEL.


Migrated from Short description of key information:
One key study, local lymph node assay is available.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:
Migrated from Short description of key information:
One key study, local lymph node assay is available.

Justification for classification or non-classification

The substance has been tested in the mouse local lymph node assay in accordance with OECD 429. Application of the classification criteria set out in CLP Regulation Annex I Section 3.4.2.2.3 results in a classification of Skin sensitiser Category 1B for the calculated EC3 value of 14% w/v in dimethylformamide.