Choline chloride

Endpoint summary

Description of key information

1) BASF, 1969 - acute oral toxicity, rats, LD50 ca. 5500 mg/kg bw
2) BASF, 1963 - acute oral toxicity, rats, LD50 ca. 3500 mg/kg bw
3) Salazar-Rodriguez/Sosa, 2004 - acute oral toxicity, rats, LD0 >= 2.79 g/kg bw, intermittent total dose LD0 >= 8.37 g/kg bw (3 consecutive days)

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:

experimental study

Adequacy of study:

weight of evidence

Study period:

1963

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well documented study result, which meets basic scientific principles

Qualifier:

no guideline followed

Principles of method if other than guideline:

A Choline chloride solution (70 % in aqua dest.) was administered to rats via the oral route.

GLP compliance:

not specified

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data available

Route of administration:

oral: unspecified

Vehicle:

other: aqua dest.

Details on oral exposure:

The substance was administered orally to rats

Doses:

5 mL of a 70% solution of Choline chloride, applied as a solution in aqua dest (30 % aqua dest.).

No. of animals per sex per dose:

no data

Control animals:

not specified

Details on study design:

no specific information available

Sex:

not specified

Dose descriptor:

approximate LD50

Effect level:

ca. 5 450 mg/kg bw

Based on:

test mat.

Remarks:

70 % Choline chloride

Remarks on result:

other: referring to a 70 % Choline chloride solution

Sex:

not specified

Dose descriptor:

approximate LD50

Effect level:

ca. 3 500 mg/kg bw

Based on:

act. ingr.

Remarks:

pure Choline chloride

Remarks on result:

other: converted that corresponding to Choline chloride 100 %

Mortality:

none reported

Clinical signs:

other: restlessness, staggering, cramps and laboured breathing

Gross pathology:

no significant findings

Interpretation of results:

other:

Remarks:

EU-GHS criteria not met

Conclusions:

The study was considered to be of high quality (reliability Klimisch 2). The substance did not show a high toxicity after a single oral application to rats. The LD50 was identified to be ca. 3500 mg/kg bw (corresponding to a 100 % Choline chloride).

Executive summary:

The acute oral toxicity of Choline chloride was investigated in rats (BASF, 1963). The rats received doses of ca. 5 mL of a 70 % Choline chloride solution (applied as a 70% Choline Chloride - 30 % auqa dest solution). No mortality was reported. The main clinical symptoms of intoxications were restlessness, staggering, cramps and laboured respiration. Therefore the oral toxicity can be characterised by a approximative LD50 of ca. 5450 mg/kg bw (referring to a 70 % Choline chloride solution). This corresponds to approximatelly 3500 mg/kg bw of 100 % Choline chloride.

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1969-06-19 to 1969-10-07

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Not all details are given in test report; however, the available data indicate that the study was well-performed.

Qualifier:

no guideline available

Principles of method if other than guideline:

A relevant guideline was not yet developed at the time the study was conducted.
An aqueous suspension of the test item with Tragacanth was administered once orally by gavage to rats with a post-observation period of 7 days.

GLP compliance:

no

Remarks:

Conduction of the study prior to GLP

Test type:

other: no data

Limit test:

yes

Species:

rat

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

no data

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 30%
- Justification for choice of vehicle: insoluble in oil
- with Tragacanth

Doses:

no data

No. of animals per sex per dose:

no data

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 7 days
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs

Sex:

not specified

Dose descriptor:

LD50

Effect level:

ca. 11 000 mg/kg bw

Based on:

test mat.

Remarks:

Choline chloride 50%

Remarks on result:

other: applied as 30 % aqueous suspension in water with tragacanth

Sex:

not specified

Dose descriptor:

LD50

Effect level:

ca. 5 500 mg/kg bw

Based on:

other: pure choline chloride

Remarks on result:

other: re-calculated from LD50 of Choline chloride 50 %

Mortality:

Observed but not quantitatively denoted; at least 5 animals in whole trial.

Clinical signs:

other: Apathy, Dyspnoe Calm behavior, accelerated respiration, individually chewing constraint, huddled posture and wet, dirty and shaggy fur

Gross pathology:

Dead Animals: 5x more or less serous smeared snout, particularly ani, diarrhoea, elsewise sepsis
Killed animals: 2x pneumonia in the right upper half of lungs, 1x reduced bodyweight, bronchopneumonia, elsewise organs with negative results

Interpretation of results:

GHS criteria not met

Conclusions:

The present study was assessed as reliable with restrictions (Klimisch 2), because not all details are given in test report. However, the available data indicate that the study was well-performed and consequently the obtained results are sufficiently reliable to assess the acute toxicity of Choline chloride in rats. The LD50 was determined to be ca. 11000 mg/kg of the test item, applied as an 30% aqueous suspension with Tragacanth. This corresponds to ca. 5500 mg/kg of the pure Choline chloride. Consequently, Choline chloride does not need to be classified as hazardous, neither according to Regulation 1272/2008/EC.

Executive summary:

In an acute oral toxicity study with a 7 d post-observation period, rats were given 11000 mg/kg bw of Choline chloride 50 %, applied as a 30 % aqueous suspension with tragacanth. The oral LD50 was determined to be ca. 11000 mg/kg of the test item, which corresponds to ca. 5500 mg/kg of pure Choline chloride. Clinical signs were apathy, dyspnoe, calm behaviour, accelerated respiration, individually chewing constraint, huddled posture and wet, dirty and shaggy fur, necropsy findings were more or less serous smeared snout (5x), particularly ani, diarrhoea, elsewise sepsis (dead animals) and pneunomia in the right upper half of lungs (2x), reduced body weight (1x), bronchopneumonia, elsewise organs with negative results (killed animals), respectively.

In summary, Choline chlroide is of very low acute oral toxicity based in the LD50 of 5500 mg/kg in rats and does therefore not need to be classified as hazardous according to Regulation 1272/2008/EC.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

3 500 mg/kg bw

Quality of whole database:

Two equivalent studies assessed with Klimisch 2 and one supporting study (Klimisch 4 because only abstracts could be retrieved) are available to cover the endpoint "Acute Toxicity: oral", hence, the available information meets fully the tonnage-driven data requirements of REACH. Additionally, all available studies revealed equivalent result, i.e. are all above the boundary value of 2000 mg/kg bw for classification, and so the outcomes of the studies are consistent.

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

Endpoint:

acute toxicity: dermal

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the physicochemical and toxicological properties suggest no potential for a significant rate of absorption through the skin

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Acute toxicity - oral:

In an acute oral toxicity study with a 7 d post-observation period (BASF, 1969), rats were given 11000 mg/kg bw of Choline chloride 50 % powder - applied as a 30 % aqueous suspension with tragacanth. The oral LD50 was determined to be ca. 11000 mg/kg of the test item, which corresponds to ca. 5500 mg/kg of pure Choline chloride. Clinical signs were apathy, dyspnoe, calm behavior, accelerated respiration, individually chewing constraint, huddled posture and wet, dirty and shaggy fur, necropsy findings were more or less serous smeared snout (5x), particularly ani, diarrhoea, elsewise sepsis (dead animals) and pneumonia in the right upper half of lungs (2x), reduced body weight (1x), bronchopneumonia, elsewise organs with negative results (killed animals), respectively.

The acute oral toxicity of Choline chloride was investigated in rats (BASF, 1963). The rats received doses of ca. 5 mL of a 70 % Choline chloride solution (applied as a 70 % Choline Chloride - 30 % aqua dest. solution). No mortality was reported. The main clinical symptoms of intoxications were restlessness, staggering, cramps and laboured respiration. Therefore, the oral toxicity can be characterised by a approximative LD50 of ca. 5450 mg/kg bw (referring to a 70 % Choline chloride solution). This corresponds to approximately 3500 mg/kg bw of the pure Choline chloride.

 

These results are obtained from two studies, which were classified as reliable with restrictions, and can therefore be used to assess the hazard of Choline chloride. With an LD50 of 3500 mg/kg bw and 5500 mg/kg bw, respectively, Choline chloride is practically nontoxic and does therefore not need to be classified as hazardous according to Regulation 1272/2008/EC. These results are supported by the results of the supporting study (Salazar-Rodriguez/Sosa) are consistent with the data provided in both the WoE-studies, so the LD0 ≥ 2.79 mg/kg bw resp. LD0 ≥ 8.37 mg/kg (three consecutive days, intermittent gavage) obtained in this study can be used to support the classification of being practically nontoxic / non- hazardous as stated in the WoE studies.

 

Acute toxicity - other routes:

In an acute toxicity study with i.p. injection and a 7 d post-observation period (BASF, 1969), mice were given a 4 % aqueous solution of choline chloride (50 %) with tragacanth. The i.p. LD50 was determined to be ca. 550 mg/kg of the test item applied in a 4 % solution, which corresponds to ca. 275 mg/kg of the pure choline chloride. Clinical signs were ventral position, myoclonus and tremor, exophthalmos, dyspnoea or accelerated and precussive respiration, cyanosis, huddled posture, sunken flanks, clotted eyes and fluffed fur, necropsy findings were sepsis (dead animals) and bracket-formed adhesions on the liver (4x), elsewise organs with negative results (killed animals), respectively.

The acute toxicity of choline chloride after intraperitoneal injection was investigated in mice (BASF, 1963). The mice received doses of ca. 0.35 mL of a 70 % choline chloride solution (applied as an 8 % solution in water). No mortality was reported. The main clinical symptoms of intoxications were restlessness, staggering, cramps and laboured respiration. The intraperitoneal toxicity with an approximative LD50 of ca. 266 mg/kg bw of 100 % choline chloride was found.

Since this route of application (intraperitoneal) is not relevant for human risk assessment, the results are not used to assess the need for classification and represent with consistent LD50(i.p.) values of 275 mg/kg bw and 266 mg/kg bw, resp., nevertheless relatively high values, the classification of Choline chloride as non-hazardous is still justified.

Justification for selection of acute toxicity – oral endpoint
One of two equally well-documented acute toxicity studies, assessed with Klimisch 2. The LD50 values of both oral studies can be considered as equivalently reliable and both above the boundary value of 2000 mg/kg bw for classification. However, the lower LD50 (3500 instead of 5500 mg/kg bw) was chosen out of precautionary principles.

Justification for selection of acute toxicity – inhalation endpoint
The test substance has a very low vapour pressure and a high melting point, so the potential for the generation of inhalable forms is low. Furthermore, the substance is distributed as an aqueous solution, so no dust with inhalable particles will be formed and therefore no acute inhalation test was performed.

Justification for selection of acute toxicity – dermal endpoint
Data waiving: According to REACH Annex VIII column 2 Testing by the dermal route is appropriate if (1) inhalation of the substance is unlikely and (2) skin contact in production and/or use is likely and (3) the physicochemical and toxicological properties suggest the potential for a significant rate of absorption through the skin. Although inhalation of Choline chloride is unlikely and skin contact may possibly occur when using Choline chloride, the latter condition does not apply. Skin absorption is influenced by several factors, i.a.:
- Molecular weight: With a molecular weight of 139.6 g/mole, absorption is possible, but not highly favoured
- LogPow: Since Choline chloride, due to its ionic structure, has a logPow of -3.77 at 25 °C, dermal absorption may practically not occur because poor lipophilicity will limit penetration into the stratum corneum.
- Water solubility: Water solubility was found to be ≥ 79.3 g/100 g and < 89.7 g/100 g (m test item / m mixture) at T = 23 °C and at T = 20 °C ± 0.5 °C, i.e. over 10 g/L. Also here, dermal absorption may practically not occur due to the high hydrophilicity of the compound.
- Skin irritation / corrosion: If the substance is a skin irritant or corrosive, damage to the skin surface may enhance penetration. Choline chloride was not classified as irritant to the skin, therefore, no additional penetration enhancement must be considered.
Hence, based on the physico-chemical properties of Choline chloride, a dermal absorption is very hindered and so unlikely. Consequently, no additional testing is required and the testing for acute toxicity via dermal route for Choline chloride can be waived.

Justification for classification or non-classification

For choline chloride, an LD50 of 3500 mg/kg bw was obtained in the most relevant key study, and therefore the substance does not need to be classified as hazardous according to Regulation 1272/2008/EC.

The LD0 ≥ 2.79 g/kg bw resp. LD0 ≥ 8.37 g/kg (three consecutive days, intermittent gavage) obtained in the study by Salazar-Rodriguez/Sosa can be used to support the classification of being practically nontoxic as stated in the key study.