Ammonium dihydrogen citrate

Endpoint summary

Description of key information

For acute oral toxicity, two key studies are available addressing the different parts of ammonium dihydrogen citrate. Based on this data, the acute oral toxicity of ammonium dihydrogen citrate (pure substance) in water is concluded to exceed 2000 mg/kg bw. Since the dermal uptake is not expected to exceed the oral uptake, it is scientifically justified to conclude that the dermal acute toxicity of the ure substance also exceeds 2000 mg/kg bw. This is supported by a study on the acute dermal toxicity of analogue ammonium sulfate. Since the substance is exclusively manufactured and marketed as aqueous solution, and exposure to aerosols is not likely, testing for acute inhalation toxicity was waived (exposure considerations).

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
See Read-across justification document attached in section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Key result

Sex:

male/female

Dose descriptor:

LD50

Remarks:

Ammonium sulphate

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Key result

Sex:

male

Dose descriptor:

LD50

Remarks:

Citric acid

Effect level:

5 040 mg/kg bw

Based on:

test mat.

Remarks:

pure ammonium dihydrogen citrate

95% CL:

> 4 520 - < 5 665

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

7 812 mg/kg bw

Based on:

test mat.

Remarks:

Ammonium dihydrogen citrate in water (≤ 55% ammonium dihydrogen citrate and ≥ 45% water)

95% CL:

> 7 006 - < 8 781

Based on the results with the source test substances Citric acid and Ammonium sulphate, the LD50 of the target substance Ammonium dihydrogen citrate can be considered >2000 mg/kg bw.

Interpretation of results:

GHS criteria not met

Remarks:

According to Regulation (EC) No. 1272/2008.

Conclusions:

Based on the results with the source test substances Citric acid and Ammonium sulphate, the LD50 of the target substance Ammonium dihydrogen citrate (pure substance) can be considered >2000 mg/kg bw.

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: In this publication an acute oral toxicity test was conducted using a similar OECDTG 423 protocol without GLP.

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

yes

Remarks:

Limited details on test animals and environmental conditions, no details on purity

GLP compliance:

no

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: No data
- Age at study initiation: 5 - 6 weeks
- Weight at study initiation: no data
- Fasting period before study: 16 hours
- Housing: no data
- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
No data

Route of administration:

oral: unspecified

Vehicle:

water

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: No data

DOSAGE PREPARATION: The test substance was dissolved in water

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Careful observations of animals, including body weight changes, mortality figures, gross lesion and behavioural and clinical abnormality, were performed for 14 days.
- Necropsy of survivors performed: yes

Statistics:

Not performed.

Preliminary study:

Not performed.

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:

No data.

Body weight:

No data.

Gross pathology:

No data.

Interpretation of results:

GHS criteria not met

Remarks:

According to Regulation (EC) No. 1272/2008.

Conclusions:

In an acute oral toxicity study with Ammonium sulfate in Wistar rats, performed equivalent to OECD423 test guideline, an LD50 >2000 mg/kg bw was determined.

Executive summary:

An assessment of acute oral toxicity with Ammonium sulfate in the rat was performed equivalent to OECD423 test guideline. Ammonium sulfate was administired by oral gavage to 3 male and 3 female Wistar rats at 2000 mg/kg bw. Careful observations of animals, including body weight changes, mortality figures, gross lesion and behavioural and clinical abnormality, were performed for 14 days. All animals were subjected to necropsy. No mortality occured. Based on the results of the study, the oral LD50 was >2000 mg/kg body weight. Based on these results, Ammonium sulfate does not have to be classified and has no obligatory labelling requirement for acute oral toxicity according to Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments).

Reference 3

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

No data.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: In this publication an acute oral toxicity test was conducted using a similar OECDTG 401 protocol without GLP.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

Limited details on test animals and environmental conditions, no details on purity, behavior and mortality were observed for 7 days after administration

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

yes

Species:

mouse

Strain:

other: ICR-JCL

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: no data
- Age at study initiation: 4 weeks
- Weight at study initiation: 20 to 24 g
- Fasting period before study: no data
- Housing: Air-conditioned room
- Diet: free access to commercial diet (CLEA CE-2)
- Water: free access to water
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
No data.

Route of administration:

oral: unspecified

Vehicle:

not specified

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: 0.5 mL/10g body weight

Doses:

4520 and 5665 mg/kg bw

No. of animals per sex per dose:

6

Control animals:

no

Details on study design:

- Duration of observation period following administration: 7 days
- Frequency of observations and weighing: Behavior and mortality were observed for 7 days after administration
- Necropsy of survivors performed: yes

Statistics:

LD50 was calculated by the method of Litchfield and Wilcoxon.

Preliminary study:

Not performed.

Key result

Sex:

male

Dose descriptor:

LD50

Effect level:

5 040 mg/kg bw

Based on:

test mat.

95% CL:

> 4 520 - < 5 665

Mortality:

No data.

Clinical signs:

Several minutes after administration the spontaneous movement of mice within the cage was observed to be activated, Fifty minutes thereafter, the mice showed motor ataxia and laid down on their side. Mydriasis and decrease in rate of respiration and heart beat were observed.

Body weight:

No data.

Gross pathology:

No abnormalities were observed.

Interpretation of results:

GHS criteria not met

Remarks:

According to Regulation (EC) No. 1272/2008.

Conclusions:

In an acute oral toxicity study with commercial Citric acid in male mice, performed equivalent to OECD401 test guideline, an LD50 >2000 mg/kg bw was determined.

Executive summary:

An assessment of acute oral toxicity with commercial Citric acid in mice was performed equivalent to OECD401 test guideline. Commercial Citric acid was administired by oral gavage to 6 male mice at 4520 and 5665 mg/kg bw. Behavior and mortality were observed for 7 days after administration. All animals were subjected to necropsy. Based on the results of the study, the oral LD50 was >2000 mg/kg body weight. Based on these results, commercial Citric acid does not have to be classified and has no obligatory labelling requirement for acute oral toxicity according to Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

The acute oral toxicity results of the source substances are of sufficient quality and adequate to fill this endpoint (both Klimisch 2)

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:

the study does not need to be conducted because exposure of humans via inhalation is not likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: dermal

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Reference 2

Endpoint:

acute toxicity: dermal

Type of information:

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

Adequacy of study:

supporting study

Justification for type of information:

The rationale to read across the data is attached in Section 13.

Reason / purpose for cross-reference:

read-across source

Strain:

Wistar

Preliminary study:

Not performed.

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:

No data.

Body weight:

No data.

Gross pathology:

No data.

Interpretation of results:

GHS criteria not met

Remarks:

According to Regulation (EC) No. 1272/2008.

Conclusions:

In an acute dermal toxicity study with Ammonium sulfate in Wistar rats, performed equivalent to OECD434 test guideline, an LD50 >2000 mg/kg bw was determined. This result is read across to ammonium dihydrogen citrate.

Executive summary:

An assessment of acute dermal toxicity with Ammonium sulfate in the rat was performed equivalent to OECD434 test guideline. Ammonium sulfate was administered to the skin surface of the clipped backs of 3 male and 3 female Wistar rats at 2000 mg/kg bw. Careful observations of animals, including body weight changes, mortality figures, gross lesion and behavioural and clinical abnormality, were performed for 14 days. All animals were subjected to necropsy. No mortality occured. Based on the results of the study, the dermal LD50 was >2000 mg/kg body weight. Based on these results, Ammonium sulfate does not have to be classified and has no obligatory labelling requirement for acute dermal toxicity according to Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments). This result is read across to ammonium dihydrogen citrate.

Reference 3

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: In this publication an acute oral toxicity test was conducted using a similar OECDTG 434 protocol without GLP.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 434 (Acute Dermal Toxicity - Fixed Dose Procedure)

Deviations:

yes

Remarks:

Limited details on environmental conditions, no details on purity, no details on duration of exposure, open application

GLP compliance:

not specified

Test type:

fixed dose procedure

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: No data
- Age at study initiation: 5 - 6 weeks
- Weight at study initiation: no data
- Fasting period before study: no data
- Housing: Individually housed in stainless-steel cages
- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
No data.

Type of coverage:

open

Vehicle:

other: water-acetone solution

Details on dermal exposure:

TEST SITE
Hair was first removed from an area of 3x4 cm^2 with an electric hair clipper, and the substance was applied in a single dose to the skin surface of the clipped backs of the animals. The application sites were not covered but the treated areas were prevented from being licked by using a plastic collar or by fixing the animals on a plastic plate.

REMOVAL OF TEST SUBSTANCE
No data.

Duration of exposure:

No data

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Careful observations of animals, including body weight changes, mortality figures, gross lesion and behavioural and clinical abnormality, were performed for 14 days.
- Necropsy of survivors performed: yes

Statistics:

Not performed.

Preliminary study:

Not performed.

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:

No data.

Body weight:

No data.

Gross pathology:

No data.

Interpretation of results:

GHS criteria not met

Remarks:

According to Regulation (EC) No. 1272/2008.

Conclusions:

In an acute dermal toxicity study with ammonium sulfate in Wistar rats, performed equivalent to OECD434 test guideline, an LD50 >2000 mg/kg bw was determined.

Executive summary:

An assessment of acute dermal toxicity with Ammonium sulfate in the rat was performed equivalent to OECD434 test guideline. Ammonium sulfate was administered to the skin surface of the clipped backs of 3 male and 3 female Wistar rats at 2000 mg/kg bw. Careful observations of animals, including body weight changes, mortality figures, gross lesion and behavioural and clinical abnormality, were performed for 14 days. All animals were subjected to necropsy. No mortality occured. Based on the results of the study, the dermal LD50 was >2000 mg/kg body weight. Based on these results, Ammonium sulfate does not have to be classified and has no obligatory labelling requirement for acute dermal toxicity according to Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

The acute dermal toxicity supporting result of the read-across substance is of sufficient quality and adequate for this dossier (Klimisch 2). The substance is not classified for acute oral toxicity. As the dermal absorption is not expected to exceed the oral absorption it is scientifically justified to conclude that the dermal LD50 will exceed 2000 mg/kg bw.

Additional information

Acute oral, source substances:

An assessment of acute oral toxicity with commercial Citric acid in mice was performed equivalent to OECD 401 test guideline. Commercial Citric acid was administired by oral gavage to 6 male mice at 4520 and 5665 mg/kg bw. Behavior and mortality were observed for 7 days after administration. All animals were subjected to necropsy. Based on the results of the study, the oral LD50 was >2000 mg/kg body weight.

An assessment of acute oral toxicity with Ammonium sulfate in the rat was performed equivalent to OECD423 test guideline. Ammonium sulfate was administired by oral gavage to 3 male and 3 female Wistar rats at 2000 mg/kg bw. Careful observations of animals, including body weight changes, mortality figures, gross lesion and behavioural and clinical abnormality, were performed for 14 days. All animals were subjected to necropsy. No mortality occured. Based on the results of the study, the oral LD50 was >2000 mg/kg body weight.

Acute inhalation:

The study does not need to be conducted because exposure of humans via inhalation is not likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size. The substance is exclusively manufactured and marketed as aqueous solution, and exposure to aerosols is not likely, testing for acute inhalation toxicity was waived.

Acute dermal:

The study does not need to conducted because the substance is concluded not to be toxic after dermal exposure.

Supporting information, source substance:

An assessment of acute dermal toxicity with Ammonium sulfate in the rat was performed equivalent to OECD434 test guideline. Ammonium sulfate was administered to the skin surface of the clipped backs of 3 male and 3 female Wistar rats at 2000 mg/kg bw. Careful observations of animals, including body weight changes, mortality figures, gross lesion and behavioural and clinical abnormality, were performed for 14 days. All animals were subjected to necropsy. No mortality occured. Based on the results of the study, the dermal LD50 was >2000 mg/kg body weight.

Justification for classification or non-classification

The substance does not need to be classified for acute oral, acute inhalation or acute dermal toxicity according to Regulation (EC) No. 1272/2008 and its amendments.