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Description of key information

Skin sensitisation in vivo (LLNA, OECD 429): not sensitising

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:
30 Jun - 3 Jul 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
yes
Remarks:
- modified LLNA = Local Lymph Node Assay - Integrated Model for Differentiation of Skin reactions (IMDS): Measurement of cell counts instead of radioactive labeling. In addition, measurements of ear swelling and ear weights were done.
Principles of method if other than guideline:
Modified LLNA (IMDS; Integrated Model for the Differentiation of Skin Reactions). Modifications are authorized in the OECD TG 429 and in the Note for Guidance SWP/2145/00 of the CPMP (2001). Information on validation of IMDS and scientific justification is given in: Vohr HW et al., Arch. Toxicol., 73, 501-509 (2000); Ehling G et al., Toxicology 212, 60-68 and 69-79 (2005).
GLP compliance:
yes (incl. QA statement)
Remarks:
Ministerium für Arbeit, Gesundheit und Soziales des Landes Nordrhein-Westfalen, Düsseldorf, Germany
Type of study:
mouse local lymph node assay (LLNA)
Species:
mouse
Strain:
NMRI
Sex:
female
Vehicle:
dimethylformamide
Concentration:
0, 2, 10, 50 %
No. of animals per dose:
6
Details on study design:
TREATMENT PREPARATION AND ADMINISTRATION:
The test item in the formulation and the vehicle were applied epicutaneously onto the dorsal part of both ears of the animals. This treatment was repeated on three consecutive days (d1, d2 and d3). The volume administered was 25 µL/ear. The used concentrations were based on the experiences with the test system and the toxic properties of the test substance.
The animals were anaesthetised by inhalation of carbon dioxide and sacrificed one day after the last application (d4). The appropriate organs were then removed. Lymphatic organs (the auricular lymph nodes) were transferred into physiological saline (PBS).
Investigations:
- weight of lymph nodes
- cell counts in lymph nodes
- stimulation index is calculated by dividing the absolute number of weight or cell counts of the substance treated lymph nodes by the vehicle treated ones.
- ear swelling
- ear weight
- body weights
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
When it was statistically reasonable, the values from treated groups were compared with those from the control group by a one-way analysis of variance (ANOVA) when the variances were homogeneous according to a homogeneity testing like Cochran's test. Alternatively, if the variances were heterogenous (p <= 0.05), a non-parametric Kruskal-Wallis test has been used (Kruskal-Wallis ANOVA) at significance levels of 5%. Two sided multiple test procedures were done according to Dunnett or Bonferroni-Holm, respectively. Outlying values in the Lymph Node weights were eliminated at a probability level of 99% by Nalimov's method. In addition, for the LLNA/IMDS the smallest significant differences in the means were calculated by Scheffels method, which according to Sachs can be used for both equal and unequal sample sizes.
Positive control results:
Alpha hexyl cinnamic aldehyde (3%, 10% and 30%), checked in regular intervals, shows a clear sensitising potential in the local lymph node assay (IMDS).
Key result
Parameter:
SI
Value:
1.1
Test group / Remarks:
2% treatment
Remarks on result:
other: see Remarks
Remarks:
Compared to vehicle-treated animals, none of the parameters measured in the test substance treated groups, i.e. cell counts and weights of the draining lymph nodes reached or exceeded the 'positive levels' defined for this assay. The cell count index was determined to be 1.1. Thus the "positive level", which is 1.4 for the cell count index, was not reached or exceeded.
Key result
Parameter:
SI
Value:
1.06
Test group / Remarks:
10% treatment
Remarks on result:
other: see Remarks
Remarks:
Compared to vehicle-treated animals, none of the parameters measured in the test substance treated groups, i.e. cell counts and weights of the draining lymph nodes reached or exceeded the 'positive levels' defined for this assay. The cell count index was determined to be 1.06. Thus the "positive level", which is 1.4 for the cell count index, was not reached or exceeded.
Key result
Parameter:
SI
Value:
1.07
Test group / Remarks:
50% treatment
Remarks on result:
other: see Remarks
Remarks:
Compared to vehicle-treated animals, none of the parameters measured in the test substance treated groups, i.e. cell counts and weights of the draining lymph nodes reached or exceeded the 'positive levels' defined for this assay. The cell count index was determined to be 1.07. Thus the "positive level", which is 1.4 for the cell count index, was not reached or exceeded.

The "positive level" of ear swelling which is 2 x 10E-2 mm increase, i.e. about 10% of the control values, has not been reached or exceeded in any dose group. No substance specific effects were determined for ear weights either. It has to be clarified that the "positive levels" mentioned above are exclusively defined for the NMRI outbred mice used for this study. Such positive limits have to be calculated for each strain of mice individually. The body weights of the animals were not affected by any treatment.

Additional detailed tables are attached below under 'Attached background material'.

Interpretation of results:
other: CLP/EU GHS criteria not met, no classification required according to Regulation (EC) No. 1272/2008.
Conclusions:
Ethane-1,2 -diol, propoxylated showed no sensitising potential in the modified Local Lymph Node Assay (IMDS) in female NMRI mice after dermal application of up to and including a 50% concentration. Additionally, no indication for a non-specific (irritant) activation was detected.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

In order to investigate the skin sensitisation potential of ethane-1,2-diol, propoxylated (CAS No.31923-84-9, EC No. 500-078-0), the modified Local Lymph Node Assay was performed according to OECD guideline 429 and under GLP conditions (rel 1-key, LLNA, OECD 429, Bayer Schering Pharma, 2009f, T6079406). 24 female NMRI mice (6 animals/test item group and 6 control animals) were used to determine if there is any specific (sensitising) or non-specific stimulating potential of the test substance. The following test substance concentrations were used: 0 (vehicle control), 2%, 10% and 50% formulated in dimethylformamide (DMF) to yield a solution. Compared to vehicle-treated animals, none of the parameters measured in the substance treated groups, i.e. cell counts and weights of the draining lymph nodes, ear weights and ear swelling, reached or exceeded the "positive levels" defined for this assay. In conclusion, the results show that ethane-1,2-diol, propoxylated has no sensitising potential in mice after dermal application of solutions with up to and including a concentration of 50%.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

The available data on skin sensitisation with ethane-1,2-diol, propoxylated (CAS No.31923-84-9, EC No. 500-078-0) do not meet the criteria for classification according to Regulation (EC) No. 1272/2008 (CLP) and are therefore conclusive but not sufficient for classification.