Dilithium sebacate

Endpoint summary

Description of key information

It is considered from all the results that the three dilithium salts exhibit classifiable acute oral toxicity, which is probably related to the lithium cation since LD50 values >2000 mg/kg bw would be expected from the dicarboxylic acids themselves (see Appendix 1 – Category Justification). No evidence of acute dermal toxicity was evident from the read across substance and it can be concluded that the three dicarboxylates are similarly devoid of classifiable acute dermal toxicity.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

16 April to 21 May 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-compliant, guideline study, available as an unpublished report.

Qualifier:

according to guideline

Guideline:

OECD Guideline 420 (Acute Oral Toxicity - Fixed Dose Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

fixed dose procedure

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

- Source: Charles River Deutschland, Sulzfeld, Germany. Animals were 8 to 10 weeks old and nulliparous and non-pregnant.
- Acclimatisation: The acclimatization period was at least 5 days before the start of treatment under laboratory conditions and animals were group housed.
- Housing: Individual housing of animals in the pilot study and group housing of four animals per cage in the main study in labeled Makrolon cages (MIV type; height 18 cm.) containing sterilized sawdust as bedding material and paper as cage-enrichment. The rats had free access to pelleted rodent diet and tap water.
- Environmental conditions: Temperature and relative humidity were set to achieve limits of 18 to 24 deg C, and 40 to 70% humidity. Rate of air exchange was at least 10 changes per hour and there was a 12 hour light/12 hour dark cycle.

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

- Preparation: The preparations (w/w) were kept at room temperature protected from light and were dosed within 4 hours after adding the vehicle to the test substance. Homogeneity was obtained to visually acceptable levels.
- Dosing: Oral gavage, using plastic feeding tubes. The test item preparations were stirred on a magnetic stirrer during dosing. The concentration of the test substance in vehicle was varied to allow constant dosage volume in terms of mL/kg body weight.

Doses:

In the absence of any other toxicity information a "Pilot study" was conducted in which single female rats were orally dosed with the test substance at 2000 or 300 mg/kg body weight. Based on the Pilot results, a fixed dose level was selected for the main study and four further females were dosed at 300 mg/kg body weight.

No. of animals per sex per dose:

For the main study a total of five female rats (including the pilot study rat) were treated at a single dose concentration.

Control animals:

no

Details on study design:

- Observations: Clinical observations were made on the day of dosing and then once daily until Day 15. Morbidity and viability checks were made twice daily and individual body weights were recorded on days 0, 8 and 15. At the end of the observation period, all animals were sacrificed by oxygen/carbon dioxide procedure and subjected to necropsy. Descriptions of all internal macroscopic abnormalities were recorded.

Statistics:

The Fixed Dose Procedure does not require any statistical analyses of the data.

Preliminary study:

In the preliminary study at 2000 mg/kg bw with a single animal, the animal was found dead on Day 2. At 300 mg/kg bw no mortality of the single animal occured. Hunched posture and piloerection were noted at both treatment levels, up to day 6 at 300 mg/kg bw.

Sex:

female

Dose descriptor:

LD50

Effect level:

> 300 mg/kg bw

Based on:

test mat.

Mortality:

During the definitive study, there were no deaths.

Clinical signs:

other: Hunched posture and piloerection were noted for all animals on Day 1.

Gross pathology:

No abnormalities were found at macroscopic post mortem examination of the animals.

Interpretation of results:

Toxicity Category IV

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The highest dose level of Dilithium adipate that did not produce mortality in Wistar rats was established as 300 mg/kg body weight and the estimated minimum lethal dose level was 2000 mg/kg body weight. Based on the mortality rate at 2000 mg/kg body weight, it was concluded that the oral LD50 value of Dilithium adipate was within the range of 300-2000 mg/kg body weight. Based on these results Dilithium adipate should be classified as Category 4.

Executive summary:

The acute oral toxicity of Dilithium adipate to female Wistar rats was determined in a GLP-compliant, fixed-dose method study following OECD guideline 420 (Latour 2015). A preliminary study indicated mortality of a single rat at 2000 mg/kg bw Dilithium adipate but no mortality of a single rat at 300 mg/kg bw Dilithium adipate. For the definitive test four further rats were treated once with 300 mg/kg bw Dilithium adipate by oral gavage and observed for the following 15 days for mortality, systemic toxicity and bodyweight gain. No deaths or significant signs of toxicity were seen. The LD50 value is within the ranges 300 -2000 mg/kg bw Dilthium adipate. Based on these results Dilithium adipate should be classified as Category 4. The study is considered to be relevant and reliable for use for this endpoint.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

discriminating dose

Value:

300 mg/kg bw

Quality of whole database:

High. Reliable, adequate and relevant data available to fulfil the tonnage-driven data requirements of REACH. Dilithium adipate (C6) is representative of the lithium salts of dicarboxylates (C6-10 lithium fatty acids) and can be read across to other category members.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

The study was performed between 12 May 2010 and 26 May 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Five male and five female Wistar (HsdRccHan:WIST) strain rats were supplied by Harlan Laboratories U.K. Ltd., Oxon, UK. On receipt the animals were randomly allocated to cages. The females were nulliparous and non pregnant. After an acclimatisation period of at least five days the animals were selected at random and given a number unique within the study by indelible ink-marking on the tail and a number written on a cage card. At the start of the study the animals weighed at least 200g, and were eight to twelve weeks of age. The weight variation did not exceed ± 20% of the mean weight for each sex.
The animals were housed in suspended solid floor polypropylene cages furnished with woodflakes. The animals were housed individually during the 24-hour exposure period and in groups of five, by sex, for the remainder of the study. Free access to mains drinking water and food (2014 Teklad Global Rodent diet supplied by Harlan Laboratories U.K. Ltd., Oxon, UK) was allowed throughout the study. The diet, drinking water and bedding were routinely analysed and were considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.
The temperature and relative humidity were set to achieve limits of 19 to 25°C and 30 to 70% respectively. Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study. The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.

The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

On the day before treatment the back and flanks of each animal were clipped free of hair.
Using available information on the toxicity of the test material, a group of five male and five female rats was treated with the test material at a dose level of 2000 mg/kg bw.
The appropriate amount of test material, moistened with distilled water, was applied as evenly as possible to an area of shorn skin (approximately 10% of the total body surface area). A piece of surgical gauze was placed over the treatment area and semi-occluded with a piece of self adhesive bandage. The animals were caged individually for the 24 hour exposure period. Shortly after dosing the dressings were examined to ensure that they
were securely in place.

Duration of exposure:

24 hours

Doses:

2000 mg /kg body weight

No. of animals per sex per dose:

5

Control animals:

not required

Details on study design:

After the 24-hour contact period the bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with distilled water to remove any residual test material. The animals were returned to group housing for the remainder of the study period.
The animals were observed for deaths or overt signs of toxicity ½, 1, 2 and 4 hours after dosing and subsequently once daily for fourteen days.
After removal of the dressings and subsequently once daily for fourteen days, the test sites were examined for evidence of primary irritation and scored according to the following scale from Draize J H (1977) "Dermal and Eye Toxicity Tests" In: Principles and Procedures for Evaluating the Toxicity of Household Substances, National Academy of Sciences, Washington DC p.31:

EVALUATION OF SKIN REACTIONS
Erythema and Eschar Formation Value
No erythema 0
Very slight erythema (barely perceptible) 1
Well-defined erythema 2
Moderate to severe erythema 3
Severe erythema (beef redness) to slight eschar formation (injuries in depth) 4
Oedema Formation
No oedema 0
Very slight oedema (barely perceptible) 1
Slight oedema (edges of area well-defined by definite raising) 2
Moderate oedema (raised approximately 1 millimetre) 3
Severe oedema (raised more than 1 millimetre and extending beyond the area of exposure) 4

Any other skin reactions, if present were also recorded.

Individual bodyweights were recorded prior to application of the test material on Day 0 and on Days 7 and 14.

At the end of the study the animals were killed by cervical dislocation. All animals were subjected to gross necropsy. This consisted of an external examination and opening of the abdominal and thoracic cavities. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.

Statistics:

No statistical analysis was performed.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: 95% confidence limits not reported

Mortality:

No deaths occurred during the study.

Clinical signs:

other: No clinical signs were observed during the course of the study.

Gross pathology:

No macroscopic findings were recorded at necropsy.

Other findings:

Individual dermal reactions are given in Table 2 and Table 3 in overall remarks section.
Well-defined erythema and very slight oedema were noted at the test site of one animal one day after dosing with very slight erythema noted two days after dosing. There were no signs of dermal irritation noted in the remaining animals.

Table 1              Individual Clinical Observations and Mortality Data

Dose Level mg/kg	Animal Number and Sex	Effects Noted After Initiation of Exposure (Hours)				Effects Noted After Initiation of Exposure (Days)
		½	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	1-0 Male	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-1 Male	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-2 Male	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-3 Male	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	1-4 Male	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-0 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-1 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-2 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-3 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-4 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

0 = No signs of systemic toxicity

See Overall remarks for Dermal Reactions Tables 2 and 3.

Table 4              Individual Bodyweights and Weekly Bodyweight Changes

Dose Level mg/kg	Animal Number and Sex	Bodyweight (g) at Day			Bodyweight Change (g) During Week
		0	7	14	1	2
2000	1-0 Male	229	247	278	18	31
	1-1 Male	241	262	293	21	31
	1-2 Male	244	271	291	27	20
	1-3 Male	236	259	293	23	34
	1-4 Male	231	255	294	24	39
	2-0 Female	208	212	223	4	11
	2-1 Female	210	219	228	9	9
	2-2 Female	200	201	219	1	1 8
	2-3 Female	202	206	209	4	3
	2-4 Female	201	209	218	8	9

Table 5              Individual Necropsy Findings

Dose Level mg/kg	Animal Number and Sex	Time of Death	Macroscopic Observations
2000	1-0 Male	Killed Day 14	No abnormalities detected
	1-1 Male	Killed Day 14	No abnormalities detected
	1-2 Male	Killed Day 14	No abnormalities detected
	1-3 Male	Killed Day 14	No abnormalities detected
	1-4 Male	Killed Day 14	No abnormalities detected
	2-0 Female	Killed Day 14	No abnormalities detected
	2-1 Female	Killed Day 14	No abnormalities detected
	2-2 Female	Killed Day 14	No abnormalities detected
	2-3 Female	Killed Day 14	No abnormalities detected
	2-4 Female	Killed Day 14	No abnormalities detected

Interpretation of results:

practically nontoxic

Remarks:

Migrated information

Conclusions:

The acute dermal median lethal dose (LD50) of the test material in the Wistar strain rat was found to be greater than 2000 mg/kg bodyweight.
s

Executive summary:

Introduction. The study was performed to assess the acute dermal toxicity of the test material in the Wistar strain rat. The method was designed to meet the requirements of the following:

OECD Guidelines for the Testing of Chemicals No. 402 “Acute Dermal Toxicity” (adopted 24 February 1987)

Method B3 Acute Toxicity (Dermal) of Commission Regulation (EC) No. 440/2008

Method. A group of ten animals (five males and five females) was given a single, 24 hour, semi occluded dermal application of the test material to intact skin at a dose level of 2000 mg/kg bodyweight. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

Mortality. There were no deaths.

Clinical Observations. There were no signs of systemic toxicity.

Dermal Irritation. Well-defined erythema and very slight oedema were noted at the test site of one animal. There were no signs of dermal irritation noted in the remaining animals.

Bodyweight. All animals showed expected gains in bodyweight over the study period.

Necropsy. No abnormalities were noted at necropsy.

Conclusion. The acute dermal median lethal dose (LD₅₀) of the test material in the Wistar strain rat was found to be greater than 2000 mg/kg bodyweight.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

High. Reliable, adequate and relevant data available to fulfil the tonnage-driven data requirements of REACH. Tested substance is representative of the lithium salts of C14-C22 fatty acids category and can be read across to other category members.

Additional information

The substances in the category are considered to be similar on the basis that they have common structures of a lithium ion varying only by the length of the fatty acid chain. As a result, it is expected that the substances will have similar, predictable properties. REACH Annex V, Entry 9, groups fatty acids and their potassium, sodium, calcium and magnesium salts, including C6 to C24, predominantly even-numbered, unbranched, saturated or unsaturated aliphatic monocarboxylic acids. Provided that they are obtained from natural sources and are not chemically modified, the substances included in REACH Annex V, Entry 9 are exempt from registration, unless they are classified as dangerous (except for flammability, skin irritation or eye irritation) or they meet the criteria for PBT/vPvB substances. As the fatty acid substances listed in Annex V are exempt, it can reasonably be interpreted that they are not considered to be hazardous to human health (with the noted potential exceptions of skin and eye irritation) or the environment. Since published reviews do not distinguish between the properties of monocarboxylic or dicarboxylic acids as a category, then the same interpretation can be applied to the dicarboxylic acids. Thus, the fatty acid components of the category ‘dilithium salts of dicarboxylic acids C6-C10’ are not expected to be hazardous. As all category members are lithium salts, any toxicity is expected to be driven by the lithium ion. Due to the close structural similarity and the narrow range of carbon chain numbers covered in this category, the acute toxicity potential is expected to be similar across the category.

Key acute oral toxicity studies were performed on the three dilithium salts of adipic, azelaic and sebacic acids in the category. A key acute dermal toxicity study on the monocarboxylic fatty acids C18 (unsaturated) lithium salts has also been reported.

The results from the Fixed Dose acute oral toxicity studies performed according to OECD 420 guidelines were consistent across the category. One or more deaths were seen at 2000 mg/kg bw for each substance, whereas no mortality occurred at 300 mg/kg bw. Based on the mortality rate at 2000 mg/kg/bw, it was concluded that the oral LD50 values of the three members of the category were within the range of 300-2000 mg/kg bw.

The acute dermal toxicity study conducted on fatty acids C18 (unsaturated) lithium salts showed no evidence of acute toxicity up to the highest dose tested (2000 mg/kg bw). Although this substance is not in the list of substances being registered, it is a lithium salt whose organic component falls within the aliphatic acid category (see Appendix 2 – Read Across Justification Document) by virtue of its chemical structure and therefore read across from data on fatty acids C18 (unsaturated) lithium salts to members of the dilithium salts of dicarboxylic acids C6-10 category is considered to be fully justified.

The lithium salts of dicarboxylic acids C6 -C10 are exclusively manufactured in situ in base oil and not in isoated form, so the potential for the generation of inhalable forms is low. Also the use of the grease forms will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be unlikely to occur. On this basis, no acute toxicity studies by the inhalation route are necessary.

Justification for selection of acute toxicity – oral endpoint
This substance is representative of the lithium salts of C6-C10 fatty acids and can be read across to other lithium dicarboxylate category members.

Justification for selection of acute toxicity – dermal endpoint
This substance is representative of the lithium salts of C6-C10 fatty acids and can be read across to other lithium dicarboxylate category members.

Justification for classification or non-classification

The oral LD50 value is within the range 300 mg/kg bw - 2000 mg/kg bw dilithium adipate.