9-Decenamide, N,N-dimethyl-

Endpoint summary

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:

07 May 2014 to 26 May 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study conducted according to OECD 429 test method.

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: approx 10 weeks
- Weight at study initiation: +/- 20% of the sex mean
- Housing: Makrolon cages, group housed
- Diet (e.g. ad libitum): pelleted rodent diet ad libitum
- Water (e.g. ad libitum): Free access to tap water
- Acclimation period:

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 to 24
- Humidity (%): 40 to 70
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12 hours light/12 hours dark

IN-LIFE DATES: From: 07 May 2014 To: 26 May 2014

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

10, 25 and 50%

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: The test substance was found to be soluble at the maximum level of 50% in the standard vehicle.
- Irritation: Slight erythema was noted on the ears of animals exposed to a concentration of 50% test substance.
- Clinical signs: Animals exposed to 100% neat test substance showed lethargy, ventral recumbancy and laboured respiration on Day 2.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: If the results indicate a SI ≥ 3, the test substance may be regarded as a skin sensitizer.

TREATMENT PREPARATION AND ADMINISTRATION: The test substance was prepared as dilutions at 50, 25 and 105 in the selected vehicle.

Positive control results:

The results of a reliability test with three concentrations of Hexylcinnamaldehyde in Acetone/Olive oil (4:1 v/v), performed not more than 6 months previously and using the same materials, animal supplier, animal strain and essential procedures were used to validate the procedure. For both scientific and animal welfare reasons, no concurrent positive control group was added to the study. An extensive data base is available with reliability checks performed each half year during at least the recent 9 years showing reproducible and consistent positive results.

Parameter:

SI

Remarks on result:

other: The SI values calculated for the substance concentrations 10, 25 and 50% were 1.9, 1.6 and 2.2 respectively.

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Mean DPM/animal values for the experimental groups treated with test substance concentrations 10, 25 and 50% were 837, 709 and 980 DPM respectively. The mean DPM/animal value for the vehicle control group was 452 DPM.

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The test substance is not be regarded as a skin sensitizer according to the recommendations made in the test guidelines. The test substance does not have to be classified and has no obligatory labelling requirement for sensitization by skin contact according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2011) (including all amendments) and the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments).

Executive summary:

Introduction

The study was carried out based on the guidelines described in: OECD, Section 4, Health Effects, No.429 (2010), EC, No 440/2008; B42: "Skin Sensitization: Local Lymph Node Assay" EPA, OPPTS 870.2600 (2003) “Skin Sensitization”.

Methods

Test substance concentrations selected for the main study were based on the results of a pre-screen test. In the main study, three experimental groups of five female CBA/J mice were treated with test substance concentrations of 10, 25 or 50% w/w on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with vehicle alone (Acetone/Olive oil (4:1 v/v)). Three days after the last exposure, all animals were injected with 3 H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised and pooled for each animal. After precipitating the DNA of the lymph node cells, radioactivity measurements were performed. The activity was expressed as the number of Disintegrations Per Minute (DPM) and a stimulation index (SI) was subsequently calculated for each group.

Results

No irritation was observed in the animals except for the very slight irritation of the ears as shown by all animals treated at 50% on Day 3. All auricular lymph nodes of the animals of the experimental and control groups were considered normal in size. No macroscopic abnormalities of the surrounding area were noted for any of the animals. Mean DPM/animal values for the experimental groups treated with test substance concentrations 10, 25 and 50% were 837, 709 and 980 DPM respectively. The mean DPM/animal value for the vehicle control group was 452 DPM. The SI values calculated for the substance concentrations 10, 25 and 50% were 1.9, 1.6 and 2.2 respectively.

Conclusion

Since there was no indication that the test substance elicits an SI ≥ 3 when tested up to 50%, the test substance was considered not to be a skin sensitizer. It was established that the EC3 value (the estimated test substance concentration that will give a SI =3) (if any) exceeds 50%. The six-month reliability check with Alpha-hexylcinnamaldehyde indicates that the Local Lymph Node Assay as performed at WIL Research Europe is an appropriate model for testing for contact hypersensitivity. Based on these results, the test substance would not be regarded as a skin sensitizer according to the recommendations made in the test guidelines. The test substance does not have to be classified and has no obligatory labelling requirement for sensitization by skin contact according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2011) (including all amendments) and the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The skin sensitisation potential of the substance was assessed in a Local Lymph Node Assay performed according to OECD TG 429, EU Method B.42 and EPA OPPTS 870.2600 [van Huygevoort, 2014]. Test substance concentrations selected for the main study were based on the results of a pre-screen test. In the main study, three experimental groups of five female CBA/J mice were treated with test substance concentrations of 10, 25 or 50% w/w on three consecutive days, by open application on the ears. Five vehicle control animals were similarly treated, but with vehicle alone (Acetone/Olive oil (4:1 v/v)). Three days after the last exposure, all animals were injected with 3 H-methyl thymidine and after five hours the draining (auricular) lymph nodes were excised and pooled for each animal. After precipitating the DNA of the lymph node cells, radioactivity measurements were performed. The activity was expressed as the number of Disintegrations Per Minute (DPM) and a stimulation index (SI) was subsequently calculated for each group. No irritation was observed in the animals except for the very slight irritation of the ears as shown by all animals treated at 50% on Day 3. All auricular lymph nodes of the animals of the experimental and control groups were considered normal in size. No macroscopic abnormalities of the surrounding area were noted for any of the animals. Mean DPM/animal values for the experimental groups treated with test substance concentrations 10, 25 and 50% were 837, 709 and 980 DPM respectively. The mean DPM/animal value for the vehicle control group was 452 DPM. The SI values calculated for the substance concentrations 10, 25 and 50% were 1.9, 1.6 and 2.2 respectively. Since there was no indication that the test substance elicits an SI ≥ 3 when tested up to 50%, the test substance was not considered to be a skin sensitizer. It was established that the EC3 value (the estimated test substance concentration that will give a SI =3) (if any) exceeds 50%. The six-month reliability check with Alpha-hexylcinnamaldehyde indicates that the Local Lymph Node Assay as performed at WIL Research Europe is an appropriate model for testing for contact hypersensitivity. Based on these results, the test substance would not be regarded as a skin sensitizer according to the recommendations made in the test guidelines.

A supporting study performed using the read-across substance N,N-Dimethyldecan-1-amide, mixture with N,N-Dimethyloctan-1-amide ( CAS No.67359-57-3) using an adaptation of the method of Ritz and Buehler is available [Kreuzmann, 1990].The test substance was used as 5% w/v formulation in 80% ethanol/20% distilled water for induction and as 2.5% formulation in acetone for challenge and epicutaneous occlusive applied to 20 guinea pigs. There were no grades of 1 produced in the test or control animals. The incidence of grade + responses in the test group (14 of 20) was compared to that of the naive control group (7 of 10). The incidence and severity of these responses in the test group were essentially comparable to those produced by the naive control group indicating that sensitization had not been induced. Therefore the mixture was classified as not sensitising.

Migrated from Short description of key information:
OECD 429, GLP LLNA study carried out in female mice using concentrations of 10, 25 and 50% in acetone/olive oil (4:1 v/v). The SI values were <3 for each of the three dose levels. The substance is not a sensitiser based on the results of this study.

Justification for selection of skin sensitisation endpoint:
GLP, Klimisch grade 1 study conducted according to OECD 429 test guideline

Justification for classification or non-classification

There was no indication that the test substance elicits an SI ≥ 3 when tested up to 50%, the test substance was considered not to be a skin sensitizer. It was established that the EC3 value (the estimated test substance concentration that will give a SI =3) (if any) exceeds 50%. Hence no classification is required under CLP.