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Description of key information

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:
29th September 2009 - 26th January 2010.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted according to the relevant OECD guidelines (OECD guideline 429) and is compliant with GLP.
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/Ca
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River UK Limited, Manston Road, Margate, Kent, UK
- Age at study initiation: 7 to 8 weeks old
- Weight at study initiation: 15.2 to 18.9 g
- Housing: The animals were housed in groups of 2 or 3 in cages.
- Diet (e.g. ad libitum): Rat and Mouse No. 1 Maintenance Diet ad libitum.
- Water (e.g. ad libitum): Water from Public Supply ad libitum.
- Acclimation period: The animals were acclimatised for at least 8 days prior to the start of dosing.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 - 22°C
- Humidity (%): 47 - 61%
- Air changes (per hr): A minimum of 15 air changes per hour.
- Photoperiod (hrs dark / hrs light): A 12 hours dark / 12 hours light cycle was in operation.


IN-LIFE DATES: From: 14th October 2009 To: 29th October 2009.
Vehicle:
dimethylformamide
Concentration:
The formulation concentrations used were 10%, 25% and 50%.
No. of animals per dose:
Five female mice per dose were used.
Details on study design:
MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay
- Criteria used to consider a positive response: A response will be considered to be positive should a Stimulation Index of ≥ 3 be obtained.

TREATMENT PREPARATION AND ADMINISTRATION:
For each formulation the appropriate amount of Polyol PX was weighed and transferred to a glass container. The control, dimethylformamide (DMF) was added and the mixture was stirred using a magnetic stirrer until the formulations were visibly homogenous.

The appropriate amount of DMF was also dispensed for administration to the vehicle control group.

The test item was administered by a single open application of 25μL of the appropriate application concentration (0, 10, 25 or 50%) into the dorsum of each ear for 3 consecutive days (Days 1 - 3). The test animals received no treatment on Days 4 and 5. On Day 6, each animal was administered with 25μL phosphate buffered saline (PBS) containing approximately 19μCi of [methyl-3H] thymidine into the lateral tail vein by intravenous injection.

5 hours after intravenous administration, the animals were killed and the major blood vessels severed. Each pair of draining auricular lymph nodes was collected from each animal. A single cell suspension of lymph node cells was prepared from each paired sample, by gentle disaggregation. The lymph node cells were washed in PBS and centrifuged.

Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
No formal statistical analyses were conducted and are not required.

Positive control results:
The Stimulation Indices in a recent positive control study were 1.7, 2.4 and 5.0 for 5%, 10% and 25% hexylcinnamicaldehyde, respectively.
Parameter:
SI
Value:
1
Test group / Remarks:
Control group
Parameter:
SI
Value:
0.9
Test group / Remarks:
Dose group Low: concentration formulation 10%.
Parameter:
SI
Value:
0.9
Test group / Remarks:
Dose group Middle: concentration formulation 25%.
Parameter:
SI
Value:
1.1
Test group / Remarks:
Dose group High: concentration formulation 50%.
Parameter:
other: disintegrations per minute (DPM)
Value:
2 715
Remarks on result:
other: Control group
Parameter:
other: disintegrations per minute (DPM)
Value:
2 348
Test group / Remarks:
Dose group Low: concentration formulation 10%
Parameter:
other: disintegrations per minute (DPM)
Value:
2 515
Test group / Remarks:
Dose group Middle: concentration formulation 25%.
Parameter:
other: disintegrations per minute (DPM)
Value:
2 879
Test group / Remarks:
Dose group High: concentration formulation 50%.

Individual Mean and Group Mean Scintillation Counts (DPM)

Treatment                      Dimethylformamide                                Polyol PX

Group                                          1                          2                       3                     4

Concentration (%)                         0                         10                     25                   50

 

Group

Animal

DPM

Group Mean DPM

Stimulation Index

1

1

2

3

4

5

2723

1865

3385

3695

1909

2715

1

2

6

7

8

9

10

711

4586

2258

1363

2823

2348

 

0.9

3

11

12

13

14

15

2467

2550

1871

3513

2176

2515

0.9

4

16

17

18

19

20

2304

3341

3475

3747

1527

2879

1.1

There were no signs of systemic toxicity noted in any animal during the observation period.

The changes in body weight (body weight gain) were considerd to be within the normal range for mice of this age and strain.

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Under the conditions of the study, treatment with Polyol PX at concentrations of up to 50% did not result in a stimulation index of greater than / equal to 3, meaning the test item is not considered to have the potential to cause sensitisation. Consequently, it does not require classification as a skin sensitiser according to CLP.
Executive summary:

Three groups of five female mice received an open application of 25uL of the test substance, Polyol PX, at three concentrations, specifically 10%, 25% and 50%, for three consecutive days (test days 1 - 3). One group of five females received only the vehicle, dimethylformamide. Three days after the final application (test day 6), each animal was intravenously injected with [methyl-3H] thymidine into the lateral tail vein and after five hours, the draining lymph nodes were collected. There were no systemic signs of toxicity noted in any animal during the observation period and changes in body weight were considered to be acceptable for this age and strain of mice. The stimulation index (SI) values for the mice treated with the test substance at 10%, 25% and 50% concentrations were 0.9, 0.9 and 1.1, respectively. Under the conditions of this study, it was determined that Polyol PX does not have the potential to cause sensitisation as treatment with Polyol PX did not achieve a stimulation index of ≥3 at concentrations of up to 50%. As a result of this, it was concluded that Polyol PX did not meet the criteria for classification as a skin sensitiser according to CLP.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

No evidence of skin sensitisation potential for Polyol PX was seen in a modern and guideline-compliant LLNA (Robertson, 2009).

The stimulation index (SI) values for the mice treated with the test substance at 10%, 25% and 50% concentrations were 0.9, 0.9 and 1.1, respectively. There is no evidence of skin or respiratory sensitisation in exposed workers. The substance is therefore not classified as a skin sensitiser.


Migrated from Short description of key information:
Polyol PX was found to be non-sensitising in a local lymph node assay. There is no evidence of skin or respiratory sensitisation in exposed workers.

Justification for selection of skin sensitisation endpoint:
Single study available for this endpoint

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

No animal data are available. There is no evidence of respiratory sensitisation in exposed workers.


Migrated from Short description of key information:
No animal data are available. There is no evidence of respiratory sensitisation in exposed workers.

Justification for classification or non-classification

The Reaction mass of 1,3-Propanediol, 2-(hydroxymethyl)-2-[(methoxymethoxy)methyl]- and 1,3-dioxane-5,5-dimethanol was not considered to be a skin sensitiser in a local lymph node assay, therefore classification is not required according no classification is required according to EC Regulation 1272/2008. There is no evidence of skin or respiratory sensitisation in exposed workers.