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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:
20.12.2017 - 20.04.2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
The solubility of the test item in test specific solvents was determined in pre-tests. The test item was insoluble in all solvents indicated by the respective OECD guidelines at the required concentrations. Even after sonication, precipitation was clearly visible with the unaided eye. Under these circumstances, in vitro skin sensitization testing according with OECD 442C, OECD 442D, and OECD 442C of the substance is not possible. Testing with precipitates is technically not feasible in case of DPRA and h-CLAT, and it is not recommended in case of the LuSens test, since a significant result cannot be obtained.
Other validated in vitro tests on skin sensitization are not available at present.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
GLP compliance:
yes
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Reference substance name:
Reaction mass of N-(hydroxymethyl)hexadecan-1-amide and N-(hydroxymethyl)stearamide
EC Number:
911-553-0
Molecular formula:
not applicable
IUPAC Name:
Reaction mass of N-(hydroxymethyl)hexadecan-1-amide and N-(hydroxymethyl)stearamide
Test material form:
solid: particulate/powder

In vivo test system

Test animals

Species:
mouse
Strain:
CBA/Ca
Sex:
female
Details on test animals and environmental conditions:
Number and Sex of Animals: 29 females
Age at First Dose: 9-11 weeks, female animals, non-pregnant, and nulliparous were used
Animal Health: The health condition of animals was examined by a veterinarian before initiation of the study
Acclimation: The animals were acclimated in identical conditions as during the experiment for 5 days prior to the start of treatment. The acclimatio
n was according to standard operation procedures.
Housing Condition: The animals were housed in IVC polycarbonate cages (5 animals percage) suspended on stainless steel racks, in a room equipped
with central air-conditioning. Room temperature of 22 ± 3 °C, relative humidity of 50 - 60 %, 12-hour light / 12-hour dark cycle.
Diet; A laboratory food ssniff (ssniff Spezialdiäten GmbH, Germany) was served ad libitum, each day approximately at the same time.
Water: The animals received tap water for human consumption. Supply of drinking water was unlimited. The quality of drinking water is periodically
monitored (including microbiological control) and recorded;
Bedding: Lignocel S3/4, Lufa - ITL GmbH, Germany
Animals Identification : Each animal was marked with permanent pen on the tail.
Each cage was affixed with a cage card containing pertinent animal and study information.
Justification for theChoice of Species: The CBA/Ca mice are the standard experimental rodent of choice and recommended by OECD Guideline No. 429.

Study design: in vivo (LLNA)

Vehicle:
dimethyl sulphoxide
Remarks:
The vehicle (DMSO) was selected from the recommended vehicles according to OECD Guideline No. 429. The test item was not soluble in the vehicle; therefore, a homogeneous suspension was obtained.
Concentration:
25 %, 50 % and 100 % w/v
The Pre-screen test was performed using a dose of 100 %. Based on the observations recorded in the
Pre-screen tests, the concentration of 100 % was selected as top dose for the main test.
No. of animals per dose:
5 (4 for pre-screen test)
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Value:
2.24
Test group / Remarks:
1000 mg/mL
Parameter:
SI
Value:
1.87
Test group / Remarks:
500 mg/mL
Parameter:
SI
Value:
1.22
Test group / Remarks:
250 mg/mL
Key result
Parameter:
EC3
Remarks on result:
not determinable
Remarks:
The EC3 value could not be calculated, since none of the tested concentrations induced a S.I. greater than the threshold value of 3.
Cellular proliferation data / Observations:
The daily clinical observation of the animals did not show visible clinical signs.
The increase of body weight was observed at all used concentrations. The increase was statistically significant at concentration of 25 %.
In comparison with the control group, a minor increase of the pooled lymph node weights at all concentrations was observed. The increase was dose dependent.

The SI values for the three treated groups were 1.22 (25 %), 1.87 (50 %) and 2.24 (100 %), respectively. The EC3 value could not be calculated, since none of the tested concentrations induced a S.I. greater than the threshold value of 3.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
These results demonstrate that the test item was not a skin sensitizer under the test conditions of this study.
Executive summary:

The skin sensitization potential of the test item was evaluated by LLNA method, which basic underlying principle is that sensitizers induce a primary proliferation of lymphocytes in the auricular lymph nodes draining the site of chemical application.

In the present study, the test item was applied to the dorsum of each ear of five female mice (CBA/Ca) per group over three consecutive days, at three concentrations. All animals survived throughout the test period without showing any clinical signs. Calculated SI values in treated groups remained under the value of 3, which is the threshold to consider the substance as a sensitizer. Therefore, it was not possible to calculate an EC3 value.