Lithium bis[ethanedioato(2-)-κO1,κO2]difluorophosphate(1-)

Endpoint summary

Description of key information

Skin sensitisation:

The study was performed in accordance with OECD Guideline 429. In this assay the test/control ratios obtained for 2.5, 5 and 10% w/v were 20.1, 15.5 and 23.7 respectively which indicates that the test substance showed the potential to induce skin sensitization (delayed contact hypersensitivity).

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2010-01-07 to 2010-01-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

2002

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Specific details on test material used for the study:

Batch No.: 08111121
Purity: 98%

Species:

mouse

Strain:

CBA/Ca

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan UK Ltd.
- Age at study initiation: approximately 8-12 weeks old
- Weight at study initiation: 17.1 to 20.7 g
- Housing: housed individually in polycarbonate cages with woodflake bedding.
- Diet (e.g. ad libitum): free access to a standard rodent diet (Rat and Mouse No. 1 Maintenance Diet).
- Water (e.g. ad libitum): freely available via polycarbonate bottles fitted with sipper tubes
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 23 °C
- Humidity (%): 40 to 70%
- Photoperiod (hrs dark / hrs light): a cycle of 12 hours continuous light and 12 hours continuous dark per 24 hours

Vehicle:

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

Concentration:

Preliminary study : 25 and 10% (w/v)
Main study: 2.5, 5 and 10% (w/v)

No. of animals per dose:

1 female per dose in the preliminary study
4 females per dose level in the main study

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: In a vehicle trial, the test substance was found to form an offwhite fine suspension at 50% (w/v) in Acetone : olive oil (4:1 v/v).
- Selection of dose levels
The maximum practical concentration for pinna dosing was 50% w/v in acetone: olive oil (4:1 v/v). However, in a previous acute oral toxicity study, deaths were seen at 300 mg/kg.
Based on this information the following concentrations were selected for the preliminary investigation: 25 and 10% w/v
Due to signs of toxicity seen after the second application in the animal dosed at 25% w/v, the results of the preliminary investigation indicated that 10% w/v was a suitable high dose level for the main phase of the study. Based on this information the following concentrations were selected for the main phase of the study: 2.5, 5 and 10% w/v

Preliminary investigation
Two females were treated at one of two concentrations of the test substance. The mice were treated by daily application of 25 μl of appropriate concentration of the test substance to the dorsal surface of each ear for three consecutive days (Days 1-3).

Main study
Groups of four mice were treated at one of three concentrations of the test substance. The mice were treated by daily application of 25 μl of appropriate concentration of the test substance to the dorsal surface of each ear for three consecutive days (Days 1-3).

Administration of 3H-methyl Thymidine
In the main phase of the study, five days following the first topical application of test substance (Day 6) all mice were injected via the tail vein with 250 μl of phosphate buffered saline containing 3H-methyl Thymidinea (3HTdR: 80 μCi/mL) giving a nominal 20 μCi to each mouse. The injection into the tail vein was carried out using a plastic syringe and needle after the mouse had been heated in a warming chamber.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Positive control results:

In this assay the test/control ratio obtained for HCA at 25% was 6.0. This indicates that HCA demonstrates the potential to induce skin sensitization (delayed contact hypersensitivity) and confirms the sensitivity ofthe technique to detect sensitization potential..

Key result

Parameter:

SI

Value:

20.1

Test group / Remarks:

2.5% w/v

Key result

Parameter:

SI

Value:

15.5

Test group / Remarks:

5% w/v

Key result

Parameter:

SI

Value:

23.7

Test group / Remarks:

10% w/v

Preliminary investigation

In the preliminary study, the Group 1 female dosed at 25% w/v was sacrificed on Day 2 of dosing due to the clinical signs seen. Greasy fur was noted post dose from Day 1, and was still apparent at sacrifice on Day 2. An hour after dosing on Day 2, a convulsion was noted lasting approximately 15 seconds, this was accompanied by tremors and partially closed eyelids. No signs of ill health or toxicity were observed for the Group 2 female dosed at 10% w/v. However the following observations were noted: Greasy fur was noted post dose from Day 1, and was still apparent at sacrifice on Day 4. No signs of irritation were seen over the dosed area at either level during the study.

Bodyweight increases were recorded for both mice over the period of the preliminary study. On the basis of the results from the preliminary investigation, 10% w/v was considered a suitable high dose level for the main phase of the study.

Main phase

In the main study, there were no deaths and no signs of ill health or toxicity observed during this study. However the following observations were noted: Greasy fur was noted for all control and test animals post-dose from Day 1. This sign had resolved completely in all but two females in Group 5 by Day 6. No signs of irritation were seen over the dosed area during the study. Losses in bodyweight were recorded for one female in Group 4, one female in Group 5 and 3 females in Group 6 during the study. All remaining animals gained weight during the study.

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Conclusions:

In this assay the test/control ratios obtained for 2.5, 5 and 10% w/v were 20.1, 15.5 and 23.7 respectively which indicates that the test substance showed the potential to induce skin sensitization (delayed contact hypersensitivity).

Executive summary:

The study was performed to assess the skin sensitization potential of the test substance using the murine local lymph node assay (LLNA) according to OECD Guideline 429.

In order to find a suitable level for the main phase of the study, a preliminary investigation was conducted. Two females were dosed at either 25 or 10% w/v in acetone: olive oil (4: 1 v/v). Results indicated that 10% w/v was a suitable high dose level for the main phase of the study.

In the main phase of the study, the mice were treated by daily application of 25 μl of each of one of these three concentrations (the mice in the preliminary phase of the study were treated by daily application of 25 μl of the material at 25 or 10% w/v) or vehicle control to the dorsal surface of both ears for three consecutive days.

In the main phase of the study, the proliferative response of the lymph node cells (LNC) from the draining auricular lymph nodes was assessed five days following the initial application, by measurement of the incorporation of ³H-methyl Thymidine ³HTdR) by ß-scintillation counting of LNC suspensions. The response was expressed as radioactive disintegrations per minute per lymph node (dpm/node) and as the ratio of ³HTdR incorporation into LNC of test nodes relative to that recorded for control nodes (test/control ratio).

In this assay the test/control ratios obtained for 2.5, 5 and 10% w/v were 20.1, 15.5 and 23.7 respectively which indicates that the test substance showed the potential to induce skin sensitization (delayed contact hypersensitivity).

Responses to the positive control substance hexyl cinnamic aldehyde (HCA), in a contemporaneous study demonstrate the reliability and sensitivity of this assay to detect skin sensitization potential in this laboratory.

The test substance is regarded as a potential skin sensitizer.

Reference 2

Endpoint:

skin sensitisation: in vitro

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro skin sensitisation study does not need to be conducted because adequate data from an in vivo skin sensitisation study are available

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Skin sensitisation:

The study was performed to assess the skin sensitization potential of the test substance using the murine local lymph node assay (LLNA) according to OECD Guideline 429.

In order to find a suitable level for the main phase of the study, a preliminary investigation was conducted. Two females were dosed at either 25 or 10% w/v in acetone: olive oil (4: 1 v/v). Results indicated that 10% w/v was a suitable high dose level for the main phase of the study.

In the main phase of the study, the mice were treated by daily application of 25 μl of each of one of these three concentrations (the mice in the preliminary phase of the study were treated by daily application of 25 μl of the material at 25 or 10% w/v) or vehicle control to the dorsal surface of both ears for three consecutive days.

In the main phase of the study, the proliferative response of the lymph node cells (LNC) from the draining auricular lymph nodes was assessed five days following the initial application, by measurement of the incorporation of³H-methyl Thymidine³HTdR) by ß-scintillation counting of LNC suspensions. The response was expressed as radioactive disintegrations per minute per lymph node (dpm/node) and as the ratio of³HTdR incorporation into LNC of test nodes relative to that recorded for control nodes (test/control ratio).

In this assay the test/control ratios obtained for 2.5, 5 and 10% w/v were 20.1, 15.5 and 23.7 respectively which indicates that the test substance showed the potential to induce skin sensitization (delayed contact hypersensitivity).

Responses to the positive control substance hexyl cinnamic aldehyde (HCA), in acontemporaneous study demonstrate the reliability and sensitivity of this assay to detect skin sensitization potential in this laboratory.

The test substance is regarded as a potential skin sensitizer.

Justification for classification or non-classification

Skin sensitisation:

In according to Regulation (EC) 1272/2008 (amendment 286/2011) Table 3.4.2, substances shall be classified as respiratory sensitisers (Category 1) if there are positive results from an appropriate animal test.

As a test/control ratio of more than 3 was recorded for all three of the concentrations tested, which indicates a positive result (Test/control of 3 or greater indicates a positive result), therefore this substance should be classified as Category 1 for skin sensitisation endpoint.