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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:
2 April 2014 – 26 May 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014
Report date:
2014

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 442B (Skin Sensitization: Local Lymph Node Assay: BrdU-ELISA)
Version / remarks:
22 July 2010
Deviations:
no
GLP compliance:
not specified
Type of study:
mouse local lymph node assay (LLNA): BrdU-ELISA

Test material

Constituent 1
Reference substance name:
1-Propanol, 2-methyl-, reaction products with 1,5-diisocyanatopentane
Cas Number:
1357171-37-9
Molecular formula:
not applicable (a generic formula cannot be provided for this UVCB substance)
IUPAC Name:
1-Propanol, 2-methyl-, reaction products with 1,5-diisocyanatopentane
Test material form:
liquid: viscous
Details on test material:
- Physical appearance: pale yellow viscous liquid
- Storage conditions: at room temperature and in nitrogen atmosphere

In vivo test system

Test animals

Species:
mouse
Strain:
other: CBS/NSLc
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Japan SLC
- Females nulliparous and non-pregnant: not specified
- Microbiological status of animals, when known: SPF
- Age at study initiation: 8 weeks old
- Weight at study initiation: not indicated
- Housing: individually in TPX cages in a breeding room
- Diet: pelleted diet CE-2 for mice and rats (available from CLEA Japan, Inc.), ad libitum
- Water: filtered tap water (Mobara City Water), ad libitum
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS (set to maintain)
- Temperature (°C): 23±2
- Humidity (%): 55±20
- Air changes (per hr): 10 or more
- Photoperiod (hrs dark / hrs light): 12/12

- IN-LIFE DATES: not indicated

Study design: in vivo (LLNA)

Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
40% and 80%
No. of animals per dose:
5
Details on study design:
PRE-SCREEN TESTS:
- Compound solubility: easily soluble in acetone:olive oil = 4:1, which was therefore used as the vehicle.
- Irritation: no irritation was observed and therefore the concentrations used in the preliminary test were also used for the main study. No further details were given on the preliminary test.

TREATMENT PREPARATION AND ADMINISTRATION:
Twenty five μL of each test solution (50μL/mouse) was dropped to the ear pinna of the mice using a micropipette. The administration was carried out in the morning, and repeated for 3 consecutive days in the same manner.
After 3 days from the third time of administration, 0.5 mL of the BrdU solution (dissolved in physiological saline at a concentration of 10 mg/mL; available from NACALAI TESQUE, INC.) per mouse was injected inter-peritoneally.

OBSERVATION
The general condition of the animals was observed once a day during the acclimation period and twice a day of the morning and evening during the test period except on Saturdays, Sundays and holidays.

EVALUATION OF RESULTS
The mean weight of the lymph nodes and the mean amount of BrdU intake for 5 mice of each group were calculated. The ratios of the averages to the values of the negative control group were calculated. For the amount of BrdU intake, the results of measurements made after 10, 20 and 30 minutes were summed up, and the value obtained by dividing the sum by 15 (3 points x 5 mice) was adopted as the amount of BrdU intake.
The evaluation of sensitization was conducted in reference to OECD 442B. In the evaluation, sensitization was regarded as pseudo-positive when the ratio of the amount of BrdU intake to the negative control (hereinafter referred to as “SI”) was more than 1.6 but more than 1.9, and regarded as positive when a SI was not less than 1.9.
Positive control substance(s):
other: 2% DNCB

Results and discussion

Positive control results:
The positive control showed an SI of 5.77.

In vivo (LLNA)

Resultsopen allclose all
Key result
Parameter:
SI
Value:
4.86
Test group / Remarks:
40%
Key result
Parameter:
SI
Value:
6.09
Test group / Remarks:
80%
Cellular proliferation data / Observations:
No changes in general condition were observed in the test animals in any of the test animal groups. Lymph node weights were 5.72 and 5.07 times higher than the negative control in the 40% and 80% treatment groups, respectively.

Any other information on results incl. tables

Table 1 Mean lymph node weight and mean amount of BrdU intake

Test animal group

Dosing concentration (%)

Lymph node weight

Amount of BrdU intake

 

 

Mean± SD (mg)

Ratio to negative control

Mean± SD (mg)

SI

Negative control

100

4.50 ±0.34

-

0.183 ±0.095

-

D-370N

40

25.76 ±3.85

5.72

0.889 ±0.462

4.86

80

22.80 ±3.04

5.07

1.114 ±0.508

6.09

DNCB

2

26.18 ±2.71

5.28

1.055 ±0.484

5.77

Applicant's summary and conclusion

Interpretation of results:
Category 1 (skin sensitising) based on GHS criteria
Conclusions:
In a BrdU-ELISA test, performed in accordance with OECD 442B, treatment of mice with 40% and 80% D-370N resulted in Stimulation Indices of 4.86 and 6.09, respectively. Based on these results, the test item is classified as Category 1 according to GHS.
Executive summary:

An LLNA study was performed according to OECD guideline 442B to assess the skin sensitizing potential of D-370N. The test item was dissolved in acetone:olive oil = 4:1 (AOO) at concentrations of 40% and 80%. Five animals were used for each treatment group. DNCB was used as positive control at a concentration of 2% and AOO was used as negative control. The Simulation Index (SI) was calculated as the ratio of the amount of BrdU intake to the negative control, for each concentration and the positive control. No changes in the general condition of the mice were observed. Lymph node weights were 5.72 and 5.07 times higher than the negative control in the 40% and 80% treatment groups, respectively. The SI were calculated to be 4.86 and 6.09 for 40% and 80% of the test item, respectively. The positive control had an SI of 5.77. Since the SI for both concentrations of the test item was >1.9, D-370N is classified as Category 1 for skin sensitization according to GHS.