Dilithium tetraborate

Endpoint summary

Description of key information

The oral LD50 value of dilithium tetraborate in Wistar rats was established to be within the range of 300-2000 mg/kg body weight.  According to the OECD 423 test guideline, the LD50 cut-off value was considered to be 500 mg/kg body weight.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Specific details on test material used for the study:

Test item storage: At room temperature

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Sex: 9 Females (nulliparous and non-pregnant). Each dose group consisted of 3 animals.
- Age at study initiation: Young adult animals (approximately 10-11 weeks old) were selected.
- Weight at study initiation: 165 to 200 g.
- Housing: polycarbonate cages (Makrolon MIV type; height 18 cm.) containing sterilized sawdust as bedding material (Lignocel S 8-15, JRS - J.Rettenmaier & Söhne GmbH + CO. KG, Rosenberg, Germany) equipped with water bottles.
- Diet: Pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany) was provided ad libitum
- Water: Municipal tap-water was freely available
- Acclimation period: At least 5 days before dosing.
- Animals were deprived of food overnight (for a maximum of 20 hours) prior to dosing and until 3-4 hours after administration of the test item.

ENVIRONMENTAL CONDITIONS
- 18 to 24°C with a relative target humidity of 40 to 70%

Route of administration:

oral: gavage

Vehicle:

other: medicinal white oil

Details on oral exposure:

VEHICLE
- Identification: MOL WO M46 medicinal white oil
- Justification for choice of vehicle: The vehicle was selected based on information provided by the Sponsor
- Lot/batch no. (if required): 208885/A
- Specific gravity: 0.833-0.893 g/cm3 (at 15°C)

A dose volume of 10 mL/kg body weight was used for each dose.

The oral route was selected as it is a possible route of human exposure during manufacture, handling or use of the test item.

The dose levels were based on the OECD test guidelines and were selected from the series 5 (lowest dose level), 50, 300 and 2000 (highest dose level) mg/kg body weight.

Doses:

The first group was treated at a dose level of 2000 mg/kg. Based on the results, two additional groups were dosed at 300 mg/kg.

No. of animals per sex per dose:

3 Females per dose group.

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Throughout the study, animals were observed for general health/mortality and moribundity twice daily, in the morning and at the end of the working day. Postdoes observations were performed at periodic intervals on the day of dosing (at least three times) and once daily thereafter. All the animals were examined for reaction to dosing and the onset,intensity and duration of these signs were recorded.
- All animals assigned to the study were subjected to necropsy and descriptions of all internal macroscopic abnormalities were recorded.
- The body weights of the animals were recorded individually on Day 1 (predose), 8 and 15.

Preliminary study:

Not applicable

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

500 mg/kg bw

Based on:

test mat.

Mortality:

At 2000 mg/kg, all animals were found dead on Day 2. At 300 mg/kg, no mortality occurred.

Clinical signs:

other: Hunched posture, uncoordinated movements, piloerection and ptosis were noted for all animals on Day 1 at 2000 mg/kg. At 300 mg/kg, hunched posture, uncoordinated movements and piloerection were noted for all animals between Days 1 and 2.

Gross pathology:

Abnormalities of the stomach (gelatinous contents and/or dark red/discoloured/thickened glandular mucosa) were found in the animals that died during the study, at macroscopic post mortem examination. Macroscopic post mortem examination of the surviving animals at termination did not reveal any abnormalities.

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

The oral LD50 value of dilithium tetraborate in Wistar rats was established to be within the range of 300-2000 mg/kg body weight. According to the OECD 423 test guideline, the LD50 cut-off value was considered to be 500 mg/kg body weight.

Executive summary:

The potential toxicity of dilithium tetraborate was investigated by administration of a single dose of the test substance by oral gavage to female rats according to OECD 423. Initially, Dilithium tetraborate was administered by oral gavage to three female Wistar rats at 2000 mg/kg body weight.  At 2000 mg/kg, all animals were found dead on Day 2. Two additional groups were dosed at 300 mg/kg body weight. At this dose level, no mortalities were observed but effects including hunched posture, uncoordinated movements and piloerection were noted for all animals between Days 1 and 2. For both dose levels, the body weight gain of the surviving animals was shown to be normal over the study period.

The oral LD50 value of dilithium tetraborate in Wistar rats was therefore established to be within the range of 300-2000 mg/kg body weight. According to the OECD 423 test guideline, the LD50 cut-off value was considered to be 500 mg/kg body weight.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

500 mg/kg bw

Acute toxicity: via inhalation route

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:

experimental study

Adequacy of study:

key study

Study period:

11th December 2017 to 28th December 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

GLP compliance:

yes

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Target temperatures of 18 to 24°C with a relative target humidity of 40 to 70% were maintained. The actual daily mean temperature during the study period was 20 to 21°C with an actual daily mean relative humidity of 43 to 50%. A 12 hour light/12 hour dark cycle was maintained. Ten or greater air changes per hour with 100% fresh air (no air recirculation) were maintained in the animal rooms.

Type of coverage:

semiocclusive

Vehicle:

CMC (carboxymethyl cellulose)

Remarks:

1%

Details on dermal exposure:

A single dose of test item was administered to the appropriate animals by dermal application on Day 1. One day before dosing, an area of approximately 5x7 cm on the back of the animals was clipped. The test item was applied in an area of approximately 10% of the total body surface, i.e. approximately 25 cm² for males and 18 cm² for females. The test item was held in contact with the skin with a dressing, consisting of a surgical gauze patch (Surgy 1D), successively covered with aluminum foil and Coban elastic bandage. A piece of Micropore tape was additionally used for fixation of the bandages in females only. The application period was 24 hours, after which the dressing was removed and the skin cleaned of residual test item using water.

Duration of exposure:

24 hours

Doses:

2000 mg/kg (bw)

No. of animals per sex per dose:

5 males and 5 females (females were nulliparous and non-pregnant).

Control animals:

no

Details on study design:

Dilithium tetraborate was administered to five Wistar rats of each sex by a single dermal application at 2000 mg/kg body weight for 24 hours. Animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed after terminal sacrifice (Day 15).

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred

Clinical signs:

other: Red discoloration of the nose was noted for one male and one female on Days 1 and/or 2 and chromodacryorrhoea of the snout was noted for two males and on female on Day 2.

Gross pathology:

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

TABLE 1 MORTALITY DATA
TEST DAY HOURS AFTER TREATMENT	1 0	1 2	1 4	2	3	4	5	6	7	8	9	10	11	12	13	14	15	'
MALES 2000 MG/KG	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	.
FEMALES 2000 MG/KG	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	.

TABLE 2 CLINICAL SIGNS
TEST DAY HOURS AFTER TREATMENT	MAX GRADE	1 0	1 2	1 4	2	3	4	5	6	7	8	9	10	11	12	13	14	15	'
MALES 2000 MG/KG
ANIMAL 1																			.
Secretion / excretion																			.
Chromodacryorrhoea (Snout)	(3)	-	-	-	1	-	-	-	-	-	-	-	-	-	-	-	-	-	.
ANIMAL 2																			.
Skin / fur																			.
Red discolouration (Nose)	(1)	-	1	1	1	-	-	-	-	-	-	-	-	-	-	-	-	-	.
ANIMAL 3																			.
Secretion / excretion																			.
Chromodacryorrhoea (Snout)	(3)	-	-	-	1	-	-	-	-	-	-	-	-	-	-	-	-	-	.
ANIMAL 4																			.
No clinical signs noted		-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	.
ANIMAL 5																			.
No clinical signs noted		-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	-	.
FEMALES 2000 MG/KG
ANIMAL 6																			.
Skin / fur																			.
General erythema (Treated skin)	(4)	-	-	-	1	1	-	-	-	-	-	-	-	-	-	-	-	-	.
Scales (Treated skin)	(3)	-	-	-	-	-	1	1	1	-	-	-	-	-	-	-	-	-	.
ANIMAL 7																			.
Skin / fur																			.
General erythema (Treated skin)	(4)	-	-	-	1	-	-	-	-	-	-	-	-	-	-	-	-	-	.
ANIMAL 8																			.
Skin / fur																			.
General erythema (Treated skin)	(4)	-	-	-	1	-	-	-	-	-	-	-	-	-	-	-	-	-	.
Red discolouration (Nose)	(1)	-	1	1	-	-	-	-	-	-	-	-	-	-	-	-	-	-	.
ANIMAL 9																			.
Skin / fur																			.
General erythema (Treated skin)	(4)	-	-	-	1	-	-	-	-	-	-	-	-	-	-	-	-	-	.
ANIMAL 10																			.
Skin / fur																			.
General erythema (Treated skin)	(4)	-	-	-	1	-	-	-	-	-	-	-	-	-	-	-	-	-	.
Secretion / excretion																			.
Chromodacryorrhoea (Snout)	(3)	-	-	-	1	-	-	-	-	-	-	-	-	-	-	-	-	-	.
- = Sign not observed

TABLE 3: MACROSCOPIC FINDINGS

ANIMAL	FINDING	DAY OF DEATH
MALES 2000 MG/KG
1	No findings noted	Scheduled necropsy Day 15 after treatment
2	No findings noted	Scheduled necropsy Day 15 after treatment
3	No findings noted	Scheduled necropsy Day 15 after treatment
4	No findings noted	Scheduled necropsy Day 15 after treatment
5	No findings noted	Scheduled necropsy Day 15 after treatment
FEMALES 2000 MG/KG
6	No findings noted	Scheduled necropsy Day 15 after treatment
7	No findings noted	Scheduled necropsy Day 15 after treatment
8	No findings noted	Scheduled necropsy Day 15 after treatment
9	No findings noted	Scheduled necropsy Day 15 after treatment
10	No findings noted	Scheduled necropsy Day 15 after treatment

Interpretation of results:

GHS criteria not met

Conclusions:

The dermal LD50 value of Dilithium tetraborate in Wistar rats was established to exceed 2000 mg/kg body weight. Based on these results, dilithium tetraborate does not have to be classified and has no obligatory labelling requirement for acute dermal toxicity according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2015) (including all amendments) and Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments).

Executive summary:

Dilithium tetraborate was administered to five Wistar rats of each sex by a single dermal application at 2000 mg/kg body weight for 24 hours. Animals were subjected to daily observations and weekly determination of body weight. Macroscopic examination was performed after terminal sacrifice (Day 15). No deaths or abnormalities were found at macroscopic post mortem examination of the animals. Based on these results, dilithium tetraborate does not have to be classified and has no obligatory labelling requirement for acute dermal toxicity according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2015) (including all amendments) and Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures (including all amendments).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Justification for classification or non-classification

On the basis of the acute toxicity by the oral route study, dilithium tetraborate is classified as Category 4, H302: Harmful if swallowed.