Dimethyl sebacate

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:

06 November 2012 to 04 April 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Fully GLP compliant and in accordance with current guidelines

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:

other: CBA/CaGl

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd, Bicester, UK
- Age at study initiation: 8 to 10 weeks
- Weight at study initiation: 17 to 20 g
- Housing: Individually in cages that conformed to the 'Code of Practice for the Housing and Care of Animals Used in Scientific Procedures' (Home Office, London, 1989).
- Diet (e.g. ad libitum): SQC(E) Rat and Mouse Maintenance Diet No 1, from Special Diets Services Ltd, Witham, UK, ad libitum
- Water (e.g. ad libitum): Mains water, ad libitum
- Acclimation period: 7 to 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 24°C
- Humidity (%): 45 to 65%
- Air changes (per hr): 15 to 20 air changes per hour
- Photoperiod (hrs dark / hrs light): The rooms were illuminated by fluorescent strip-lights for twelve hours daily.

IN-LIFE DATES: From: 06 November 2012 To: 20 November 2012

Vehicle:

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

Concentration:

Group 1: Vehicle control
Group 2: low concentration (25% v/v)
Group 3: Intermediate concentration (50% v/v)
Group 4: High concentration (100% v/v)

No. of animals per dose:

4 animals per dose

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: Not reported
- Irritation: Negative
- Lymph node proliferation response: Not applicable

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response: The sensitivity and reliability of the test system was checked at least every six months. Preferred substances are a-hexylcinnamaldehyde (CAS Number 101-86-0) and mercaptobenzothiazole (CAS Number 149-30-4). A Stimulation Index of 3.0 or greater is expected from these substances.

TREATMENT PREPARATION AND ADMINISTRATION: Formulations were freshly prepared as required using 80% v/v acetone in olive oil on Days 1, 2 and 3. The formulations were stored at room temperature, in sealed, air-tight containers prior to dosing. Each mouse was manually restrained with both auditory pinnae left free. The outer aspect of both pinnae of each mouse was treated by direct application of the appropriate test or control formulation (0.025 mL/pinna) dispensed from an automatic micro pipette.

Positive control substance(s):

other: a-hexylcinnamaldehyde (CAS Number 101-86-0) and mercaptobenzothiazole (CAS Number 149-30-4).

Statistics:

Not applicable

Positive control results:

Positve control not included in this study but checked at least every six months.

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

Scintillation fluid with 5% w/v trichloroacetic acid: NA Vehicle control: NA Test article, 25% w/v: 1.8 Test article, 50% w/v: 1.9 Test article, 100 % w/v: 2.2 The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0.

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Scintillation fluid with 5% w/v trichloroacetic acid: 48 DPM Vehicle control: 1386 DPM Test article, 25% w/v: 2474 DPM Test article, 50% w/v: 2605 DPM Test article, 100 % w/v: 3056 DPM

Table 1
Observations, Body weights and Mortality data – Preliminary Screening Test

 

			Observations (Days)
Concentration (% v/v in AOO)	Animal number	Body weight on Day –1 (g)	1	2	3	4	5
100	416	18	P	P	P	P	ü

 

Key

AOO       80% v/v acetone in olive oil

P              Greasy fur to head and neck

ü             No clinical signs seen

Table 2
Scintillation counts and stimulation indices

 

Sample identity		Number of sites yielding  lymph nodes		Disintegrations per minute* (DPM)		Disintegrations  per minute per node (DLM)		Stimulation Index (SI)
Scintillation fluid with 5% w/v trichloroacetic acid		--		48		--		--
Vehicle control		8		1386		173		--
Test article, 25% v/v		8		2474		309		1.8
Test article, 50% v/v		8		2605		326		1.9
Test article, 100% v/v		8		3056		382		2.2

 

* All scintillation counts corrected for the blank

SI =        Test group DLM value     

                Control group DLM value

 

Table 3
Body weights

			Body weights (g)
Concentration (% v/v)	Group number	Animal number	Day -1	Day 6
Vehicle	1	417418419420	19191920	19201921
25	2	421422423424	20191918	20192019
50	3	425426427428	17191919	18202019
100	4	429430431432	19191820	19192020

 

 

 

Interpretation of results:

GHS criteria not met

Remarks:

Migrated information

Conclusions:

The Local Lymph Node Assay demonstrated that Dimethyl Sebacate does not have the potential to cause skin sensitisation.
The test article did not meet the criteria for classification as a sensitiser according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

Executive summary:

This study was conducted to assess the potential of the test article, Dimethyl Sebacate, to cause skin sensitisation in the mouse.

Following a preliminary screening test using the undiluted test article, the test article was prepared for administration at 25, 50 and 100% v/v in 80% v/v acetone in olive oil. Groups of four female CBA / CaCrl mice were subjected to topical applications of vehicle or of one of the test formulations to the outer aspect of the auditory pinnae once daily on Days 1, 2 and 3. On Day 6 a 20 µCi dose of tritiated ³H-methyl thymidine was injected intravenously into each mouse. Approximately five hours later the auricular lymph nodes were recovered from each animal. The nodes from mice subjected to the same treatment were pooled and suspensions of the cellular components of the lymph nodes were prepared in 5% w/v trichloroacetic acid and processed through a scintillation counter.

Test results are expressed in terms of Stimulation Indices, the ratios of the mean scintillation count per group obtained from the test groups relative to the corresponding mean scintillation count from controls. The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0.

	Concentration of test article in applied formulation (%w/v)
	25%	50%	100%
Stimulation Index	1.8	1.9	2.2

The Local Lymph Node Assay demonstrated that Dimethyl Sebacate does not have the potential to cause skin sensitisation.

The test article did not meet the criteria for classification as a sensitiser according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

 

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

This study was conducted according to GLP and OECD 429 guideline to assess the potential of the test article, DimethylSebacate, to cause skin sensitisation in the mouse.

Following a preliminary screening test using the undiluted test article, the test article was prepared for administration at 25, 50 and 100% v/v in 80% v/v acetone in olive oil. Groups of four female CBA / CaCrlmice were subjected to topical applications of vehicle or of one of the test formulations to the outer aspect of the auditory pinnae once daily on Days 1, 2 and 3. On Day 6 a 20 µCidose oftritiated³H-methyl thymidine was injected intravenously into each mouse. Approximately five hours later the auricular lymph nodes were recovered from each animal. The nodes from mice subjected to the same treatment were pooled and suspensions of the cellular components of the lymph nodes were prepared in 5% w/vtrichloroaceticacid and processed through a scintillation counter.

Test results are expressed in terms of Stimulation Indices, the ratios of the mean scintillation count per group obtained from the test groups relative to the corresponding mean scintillation count from controls. The threshold level for the Stimulation Index to be considered a positive indicator of the potential to cause skin sensitisation is 3.0.

	Concentration of test article in applied formulation (%w/v)
	25%	50%	100%
Stimulation Index	1.8	1.9	2.2

The Local Lymph Node Assay demonstrated that Dimethyl Sebacate does not have the potential to cause skin sensitisation.

The test article did not meet the criteria for classification as a sensitiser according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).

 

Migrated from Short description of key information:
The Local Lymph Node Assay in the mice was performed according to OECD 429 guideline and GLP procedures. Dimethyl Sebacate was not demonstrated to be a skin sensitizer under the test conditions.

Justification for selection of skin sensitisation endpoint:
The study is performed according to GLP and OECD 429 guideline.

Justification for classification or non-classification

No skin sensitization potential was observed in a mouse local lymph node assay conducted with Dimethyl Sebacate. Hence, the substance does not qualify for skin sensitization classification according to EC (67/548/EEC) or CLP (EC 1272/2008) criteria.