2,6,10,15,19,23-hexamethyltetracosane

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2,6,10,15,19,23-hexamethyltetracosane

EC Number:

203-825-6

EC Name:

2,6,10,15,19,23-hexamethyltetracosane

Cas Number:

111-01-3

Molecular formula:

C30H62

IUPAC Name:

2,6,10,15,19,23-hexamethyltetracosane

Test material form:

other: liquid

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/J

Sex:

female

Study design: in vivo (LLNA)

Vehicle:

propylene glycol

Concentration:

25, 50 and 100%

No. of animals per dose:

5

Results and discussion

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

ca. 2.1

Variability:

0.6

Test group / Remarks:

25% squalane

Results 2

Key result

Parameter:

SI

Value:

ca. 2.8

Variability:

0.3

Test group / Remarks:

50% squalane

Results 3

Key result

Parameter:

SI

Value:

ca. 2.8

Variability:

1.3

Test group / Remarks:

100% squalane

Results 4

Key result

Parameter:

SI

Value:

ca. 2.3

Variability:

0.7

Test group / Remarks:

commercial AMYRIS squalane

Any other information on results incl. tables

Mean number of Proliferating Cells in the Lymph Nodes of each treatment group :

Treatment	Vehicule	Mean total Cells in Node	Mean % BrdU + LNC	Mean Lymphocyte Proliferation ((BrdU+)
Naive control	-	1771283	1.24	16710
Vehicule control	-	1698250	1.64	11327
Positive control	propylene glycol	12619900	1.74	221063
25% Amyris squalane	propylene glycol	3052350	0.82	23468
50% Amyris squalane	propylene glycol	3984800	0.83	32107
100% Amyris squalane	-	4467433	1.22	46437
100% commercial squalane	-	5635450	0.72	38087

Ear thickness (mm)

	Mean ear thickness (mm)			Change %
Treatment	Pre-dosing (day1)	48hrs (day3)	End of life (day6)	day3 - day1	day6 -day1
Naive control	0.20	0.20	0.20	0	0
Vehicule control	0.20	0.20	0.21	0	5
Positive control	0.19	0.25	0.26	31.6	36.8
25% Amyris squalane	0.20	0.20	0.20	0	0
50% Amyris squalane	0.20	0.21	0.21	5	5
100% Amyris squalane	0.19	0.19	0.20	0	5.3
100% commercial squalane	0.19	0.21	0.20	10.5	5.3

Simulation index results:

Naive group : SI = 1.0 ± 0.5 Vehicule control group : SI = 1.0 ± 0.5 Positive control group : SI = 19.5 ± 7.1 25% studied squalane group : SI = 2.1 ± 0.6 50% studied squalane group : SI = 2.8 ± 0.3 100% studied squalane group : SI = 2.8 ± 1.3 100% commercial squalane : SI = 2.3 ± 0.7

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Topical application of the test article Squalane at 25%, 50% and 100% resulted in SI value less than 3; therefore this test article is not a dermal sensitizer in the Local Lymph Node Assay.

Executive summary:

The LLNA assay was conducted with seven separate groups of healthy female mice (5 animals per group). Three groups were treated with increasing concentrations of the test article (25, 50 and 100% squalane in propylene glycol). A vehicule control group was treated with propylene glycol and another group was treated with the positive control (25% HCA in propylene glycol). An additionnal control (commercial squalane) was supplied by the sponsor as a verification of similar toxicological response from a substance analogous to the test article but obtained from a different manufacturing procee. The naive control group was sham-treated to provide baseline value. The test article solutions, vehicule control and positive control were administratde by topical application to the dorsum of each ear, once daily for three consecutive days.

The mice were given an intraperitoneal injection of thymidine analog 5 -bromo-2'-deoxy-uridine (BrdU) five days following the initial dose and five hours prior to the sacrifice. At sacrifice the aurocular lymph nodes were isolated, single cell suspensions of lymph node cells (LNC) were generated and the LNC suspensions were analyzed by flow cytometry for BrdU incorporation and the total LNC. The amount of proliferation was determined as a measure of proliferation response of the local lymph node. The stimulation index (SI) was calculated by dividing the proliferative response of each test article treated aniaml by the mean proliferative response of the vehicule control group, or, for the 100% test article and 100% commercial squalane group, by the mean proliferative response of the naive group. The mean SI ± standard deviation was calculated for each group.Test article groups taht yielded an SI > 3 were characterized as sensitizing substances.

The SI of the positive control group was 19.5. The group SI values for the test article at 25, 50 and 100% were 2.1, 2.8 and 2.8 respectively. The group SI value for the commercial squalane was 2.3.

Topical application of the test article squalane at 25, 50 and 100% in propylene glycol resulted in SI values less than 3. Therefore, tis test article is not a dermal sensitizer in the Local Lymph Node Assay.