Citric acid

Endpoint summary

Description of key information

An acute oral LD50 value of 5400 mg/kg bw in mouse is reported in a reliability 2 study which is broadly equivalent to the OECD test guideline 401 (Roche 1981).

An acute dermal LD50 value of >2000mg/kg bw in rat was determined in a reliable study conducted according to OECD 402 and in compliance with GLP (Safepharm, 2006; rel 1).

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

Study period:

from 4 March 1981 to 3 April 1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Equivalent to guideline study with acceptable restrictions.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Principles of method if other than guideline:

Groups of 5 mice of each sex were given a single gavage dose with observation for mortality for 10 days. Clinical observations were made at 2 h and 24 h after treatment; body weights were only recorded prior to dosing. The observation period was 10 days instead of 14 recommended by guideline.

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Species:

mouse

Strain:

other: Füllinsdorf Albino (SPF)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hoffmann-La Roche & Co. Ltd, Company breeding farm: Tierfarm Füllinsdorf. (no further details)
- Age at study initiation: not stated
- Weight at study initiation: 20 g
- Fasting period before study: not stated
- Housing: 5/Macrolon type III cage
- Diet: standard diet ad libitum
- Water: drinking water ad libitum
- Acclimation period: not stated

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 1
- Humidity (%): 50 +/- 10
- Air changes (per hr): 20-25
- Photoperiod (hrs dark / hrs light): 12 h/12 h

IN-LIFE DATES: (main study) From: 1981-03-24 To:1981-04-03

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: (main study) 150-600 mg/ml

MAXIMUM DOSE VOLUME APPLIED: 20 ml/kg bw

Doses:

0, 3, 4.2, 6, 8.5, 13 g/kg bw

No. of animals per sex per dose:

5

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 10 days
- Frequency of observations and weighing: clinical observations at 2 h and 24 h following treatment; observation for mortality daily for 10 days; body weights recorded only prior to treatment
- Necropsy of survivors performed: no
- Other examinations performed: none

Statistics:

probit analysis

Sex:

male/female

Dose descriptor:

LD50

Effect level:

5 400 mg/kg bw

95% CL:

4 500 - 6 400

Remarks on result:

other: observation limited to 10 days

Mortality:

No deaths at 3 g/kg bw, death of all exposed within 24 h at 8.5 g/kg bw, and above. See table 1.

Clinical signs:

other: Clinical observations were limited to 2 h and 24 h after treatment; the descriptions given are very limited. See table 1.

Gross pathology:

Not examined.

Other findings:

None.

Table 1: Number of animals dead and with evident toxicity and time range within which mortality occurred

Dose (g/kg bw)	Mortality (dead/total)	Time of death (within)	Overt toxicity
	Combined (5 male, 5 female)*		2 h	24 h
Control	0/10	-	none	none
3	0/10	-	none	none
4.2	2/10	24 h	none	none
6	7/10	24 h	slight relaxation	none
8.5	10/10	24 h	death	-
12	10/10	24 h	death	-

* Separate data for each sex not given

Interpretation of results:

GHS criteria not met

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

A study conducted according to a protocol that was similar to OECD 401, but limited in some respects and without GLP status, identified an acute oral LD50 value of 5.4 g/kg bw for male and female mice.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 400 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:

21/10/2004-23/01/2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study was conducted according to the appropriate OECD guideline and in complikance with GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS

- Source: Charles River (UK) Ltd, Margate, Kent, UK

- Age at study initiation: 8-12 weeks

- Weight at study initiation: minimum 200g

- Housing: solid-floor polypropylene cages furnished with woodflakes. Individually housed during the exposure nperiod and in groups of five, by sex, for the remainder of the study.

- Diet: Certified rat and mouse diet (code 5LF2), ad libitum

- Water: mains drinking water, ad libitum

- Acclimation period: minimum 5 days

ENVIRONMENTAL CONDITIONS

- Temperature (°C): 19-25

- Humidity (%): 30-70

- Air changes (per hr): minimum 15

- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: To:

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE

- Area of exposure: the back

- % coverage: 10%

- Type of wrap if used: surgical gauze, semi-occluded with a piece of self-adhesive bandage.


REMOVAL OF TEST SUBSTANCE

- Washing (if done): the bandage was removed after the exposure period, and the treated skin and surrounding hair wiped with cotton wool moistened with distilled water to remove any residual test material.

- Time after start of exposure: 24h

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mg/kg

- For solids, paste formed: no. The appropriate amount of test material, moistened with distilled water, was applied as evenly as possible

Duration of exposure:

24 hours

Doses:

2000 mg/kg

No. of animals per sex per dose:

5M,5F

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days

- Frequency of observations and weighing: The animals were observed for deaths and overt signs of toxicity 1/2, 1, 2 and 4 hours after dosing. Individual bopdy weights were recorded prior to application of the test material on day 0 and on days 7 and 14.

- Necropsy of survivors performed: yes

- Other examinations performed: clinical signs, body weight,organ weights, histopathology, other: The gross necropsy 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.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

There were no deaths.

Clinical signs:

other: There were no signs of systemic toxicity.

Gross pathology:

No abnormalities were noted at necropsy.

Other findings:

None reported.

Interpretation of results:

GHS criteria not met

Conclusions:

The LD50 value of >2000mg/kg bw was determined in a reliable study conducted according to an appropriate test protocol.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Additional information

Citric acid has low toxicity via the oral route as reflected by the LD₅₀ of 5400 mg/kg bw in mouse reported in the key study (Roche, 1981; Rel 2).

A second, reliability 2 study further supports this finding with LD₅₀ values of 5790 mg/kg bw and 11700 mg/kg bw in mouse and rat respectively (Yokotani 1971). The study by Roche in mouse was chosen as the key study because it is the most recent, with observation period closer to that of guideline (10 days) than in the study by Yokotani (7 days) in rat. This choice has no implication on classification, although the LD50 in rat in the supporting study appears to be significantly higher relative to the result in mouse in the key study. No reliable data are available for the inhalation route, although two reports on the tussigenic potential of citric acid are included (Zelenak 1982, Forsberg and Karlsson, 1986; rel 4).

Citric acid has low acute toxicity via the dermal route, with and LD50 of >2000 mg/kg bw in rat (Safepharm, 2006; Rel 1).

Justification for classification or non-classification

Based on the available information on the acute oral and dermal toxicity of citric acid, no classification is required according to Regulation (EC) No. 1272/2008.