Malic acid

Endpoint summary

Description of key information

Acute toxicity - Malic acid is conisdered to exhibit low  acute toxicity and is widely used in food.

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Experimental data reporetd in peer reviewed journal

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

no

Remarks:

Study date preceeds implementation of GLP regulations

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

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: 25%
- Amount of vehicle (if gavage): No data

MAXIMUM DOSE VOLUME APPLIED: No data

Doses:

No data

No. of animals per sex per dose:

5 male / 5 female

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: No data
- Necropsy of survivors performed: No data

Sex:

male/female

Dose descriptor:

LD50

Effect level:

3 500 mg/kg bw

Based on:

test mat.

Mortality:

No data

Clinical signs:

other: Ataxia, prostration, convulsions and death

Gross pathology:

No data

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute oral LD50 in the rat is reported to be 3500 mg/kg body weight

Executive summary:

The acute oral LD50 in the rat is reported to be 3500 mg/kg body weight

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

3 500 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Study period:

18 May 2010 to 9 June 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study compliant with GLP and test guidelines and fulfils requirements of Annexes VII - X of Regulation (EC) 1907/2006 of 18 December 2006 concerning REACH. For read-across justification see Section 13.

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

Principles of method if other than guideline:

The maximum practical dose concentration was used. The target dose of 5 mg/L was not possible to achieve from the atmosphere generating system and the mean achieved exposure was limited to 1.306 mg/L air (4 h)

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Crl:CD(SD)IGS BR, SPF sprague-Dawley rats obtained from Charles RIver Deutschland GmbH, Sulzfeld, Germany
- Age at study initiation: 8-9 weeks
- Weight at study initiation: male mean = 399.4g (range = 385 - 412g); female mean = 231.8g (range = 213 - 254g).
- Fasting period before study: not applicable
- Housing: Type III Makrolon cages with wire mesh lids
- Diet (e.g. ad libitum): Ssniff R/M-H rat and mouse maintenance diet
- Water (e.g. ad libitum):acidified tap water (adjusted to >pH 3 with HCl) via automated system, ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): Meam 19.7°C range 19.2 to 20.2°C
- Humidity (%): Mean 64% range 52 to 79% RH
- Air changes (per hr): 12/h
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 18 May 2010 To: 9 June 2010

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

clean air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Nose only apparatus, using a two chamber system with tota volume of 19L. There are 20 ports in the chamber for insertion of rat holding /exposure tubes. Food and water withdrawn from rats during exposure.
- Exposure chamber volume: 19L
- Method of holding animals in test chamber: inhalation restraining tubes attached to the chamber
- Source and rate of air: Obtained from central pressure pump and delivered at rate of 1040 L/h
- Method of conditioning air: humidity reduced to circa 10% and filtered oil-free
- System of generating particulates/aerosols: a dust generator from TSE Systems GmbH was used according to Budiman. A powder cake, (5g pressed into asteel cylinder at 5 tonnes force, was used to fill the dust generator from which a scraper removed particles to be picked up by a clean air stream.
- Method of particle size determination: The size of the dust particles was analysed with a cascade impactor (Berner-Impaktor Type LPI4/0,06/2 from Hauke KG, Gmunden, Austria). It contains nine steps with cut-off diameters from 0.06 µm to 16 µm. 5.65 litres/minute of the test substance/air mixture were passed through the impactor within 2 minutes and the amount which settled on the individual steps was determined gravimetrically. The site of collection was the same as for the analysis - breathing zone. Calculation of the mean particle size (mass median aerodynamic diameter, MMAD), used the probit of the fraction of masses smaller then the cut-off diameters plotted against the logarithm of the cut-off diameters and the linear regression of this graph was calculated, preferring the data around 50 %. The diameter, where the regression gives a probit of 5 (corresponding to a fraction of 50 %) is the mass median diameter. The quotient of the diameter at a probit of 6 (corresponding to a fraction of 84 %) to the MMAD is the geometric standard deviation (GSD). .
- Treatment of exhaust air: extracted via fume cupboard
- Temperature, humidity, pressure in air chamber:

TEST ATMOSPHERE
- Brief description of analytical method used: gravimetric analysis - dust collection 8 times during course of exposure
- Samples taken from breathing zone: yes. The dust was collected 8 times during the exposure in plastic pipette-tips filled with cottonwool which were inserted into the inhalation facility through a separate hole between two inhalation tubes. The site of collection was within the outer chamber. The inner diameter of the tips was 7 mm. Accurately measured volumes of air with the dust were collected at a rate of 1.4 litres per minute which means a velocity of 0.7 m/sec in the tips. The exact amount of collected air was measured by a gas meter (Labor- Experimentiergaszähler, size 00, 2 to 120 L/h, Ritter Apparatebau GmbH, D-44892 Bochum). Each filter-tip was dried and weighed before sampling. After sampling dry air (< 10 % humidity) was passed through them until the weight was constant. The difference in the weights before and after sampling divided by the volume of air sampled is the
concentration of the dust.

VEHICLE
- Composition of vehicle (if applicable): filtered air
- Concentration of test material in vehicle (if applicable): nominal concentration = 34.5 mg/L. Achieved concentration was 1.306 mg/L or 3.8% of output

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: Since a concentration of 5 mg/L could not be reached, no separator for large particles was used as this would reduce somewhat also the small particles. From preliminary experiments it was known that grinding of the test substance also does not reduce the MMAD.
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): The calculated mass median aerodynamic diameter (MMAD) of the test substance dust in the two determinations was 15.54 and 11.92 µm, with a geometric standard deviation (GSD) of 3.40 and 3.13.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

The actual concentration of the test substance aerosol was analysed 8 times during each 4-hour exposure period.

Duration of exposure:

4 h

Concentrations:

The dust was collected 8 times during the exposure in plastic pipette-tips filled with cottonwool which were inserted into the inhalation facility through a separate hole between two inhalation tubes. The site of collection was within the outer chamber. The inner diameter of the tips was 7 mm. Accurately measured volumes of air with the dust were collected at a rate of 1.4 litres per minute which means a velocity of 0.7 m/sec in the tips. The exact amount of collected air was measured by a gas meter (Labor- Experimentiergaszähler, size 00, 2 to 120 L/h, Ritter Apparatebau GmbH, D-44892 Bochum). Each filter-tip was dried and weighed before sampling. After sampling dry air (< 10 % humidity) was passed through them until the weight was constant. The difference in the weights before and after sampling divided by the volume of air sampled is the concentration of the dust.

No. of animals per sex per dose:

Five

Control animals:

no

Details on study design:

Preliminary investigation:
Prior to commencing the main study, atempts were made to produce a dust atmosphere containg up to 5 ng test substance/L air.
First powder cakes with a force of 10 tons were produced. They were too hard and the scraper could not remove the powder but blocked. Powder cakes pressed with 5 tons were found to be suitable. The highest technically feasible dust concentration was 0.9 to 1.0 mg/L. The mean aerodynamic diameter (MMAD) of the dust was 8 to 12 µm and therefore higher than 4 µm. It was tried to reduce the MMAD by grinding the test substance in a ball mill (Pulverisette, 2 balls, 180 rpm, 10 minutes) and sieving through a 0.15 mm sieve. But this pre treatment did not reduce the MMAD and was omitted for the main experiment. Obviously the hardness of the test substance is too low and the force during the grinding forms new agglomerates.
As the limit concentration of 5 mg/L was not reached, also no separator for large particles was used as this would decrease also the smaller particles.

Several rats were then exposed to varying concentrations to determine potentail toxicity and to provide dose-ranging information.

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Behaviour, reactions and physical signs of each of the animals were observed 1, 2, 3, 4, 5 and 6 hours after the start of exposure, twice a day on the first day after exposure, and then at least once a day for a total of 2 weeks.
The individual body weight of each animal was determined at receipt, immediately before exposure, and 1, 3, 7 and 14 days p.a. Body weight gain was calculated between the measurements and in relation to the weight before administration.
- Necropsy of survivors performed: yes

Statistics:

No data

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 1.306 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: limit dose of 5mg/L could not be achieved. 1.306 mg/L was maximum feasible atmosphere concentration.

Mortality:

There were no deaths from exposure to 1.306 mg fumaric acid/L air in a four hour nose-only exposure study.

Clinical signs:

other: No clinical signs of reaction to treatment observed for any rat throughout the study.

Body weight:

Animals lost weight on day after exposure, probably attributable to the period of time spent in the exposure holding tube rather than attributable to treatment-related effects. Subsequent bodyweight gains, recorded for all rats, were satisfactory.

Gross pathology:

No macroscopic abnormalities noted during necropsy.

Other findings:

No sex related differences observed in this study.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Fumaric acid did not elicit any indications of systemic toxicity following exposure of rats to 1.306 mg/L for 4 hours. Based on granulometry data and the virtual absence of particles in the size range 1-10 um, it was theoretically predicted that no adverse effects would follow inhalation exposure to rats. Since the human respirable and inhalable ranges are greater than those for rats, it was considered necessary to confirm in vivo the expected / predicted effects from the granulometry results. This study confirms that the nature of the fumaric acid powder means that human inhalation exposure is unlikely and, on the basis of the rat results, unlikely to cause any adverse effects even at high atmospheric concentrations.
No classification for inhalation toxicity is required for fumaric acid under Directive 67/548/EEC, the current EU Classification, Labelling and Packaging Regulation (EC) No 1272/2008 of 16 December 2008 or in accordance with the Global Harmonised System (see IUCLID section 2)

Executive summary:

Fumaric acid was administered as a dust by inhalation to Sprague Dawley rats for 4 hours in a nose-only inhalation device. The target concentration for a limit test, 5 mg/L, could not be achieved. The maximum technically feasible concentration was administered - the analysed concentration of the dust in the atmosphere was 1.306 mg/L air.

Five male and five female rats were used. The chamber was 19 L in size and was operated with 1040 L air/dust per hour. Chamber temperature ranged from 19.6 to 21.7 °C, the relative humidity from 7.0 to 22.0 %. Methods and investigations were performed in accordance with the OECD Guideline 403 and with the Council Regulation (EC) No 440/2008, Method B.2.

All animals survived till the end of the study and no clinical signs of reaction to treatment were obseved.

Body weights were recorded prior to and at intervals following the day of the exposure. The animals lost weight the first day after the exposure (possibly due to restraint during exposure). Subsequently all animals gained weight. All animals were normal at the scheduled necropsy.

The mean actual dust concentration was 1.306 mg/L. A higher output was not possible for a 4 hour operation period. The calculated mass median aerodynamic diameter (MMAD) of the test substance dust in the two determinations was 15.54 and 11.92 µm, with a geometric standard deviation (GSD) of 3.40 and 3.13. But as the limit concentration of 5 mg/L could not be reached, no separator for large particles was used as this would reduce somewhat also the small particles. Grinding of the test substance did also not reduce the MMAD.

The inhalation exposure of rats to fumaric acid at the maximal technically feasible concentration of 1.306 mg/L did not produce signs of toxicity. All animals survived and no adverse effects were observed during the 14-day observation period. The acute median lethal concentration for four hour inhalation exposure (LC50) of fumaric acid for male and female rats was greater than the maximum practically achievable atmosphere concentration of 1.306 mg/L.

Read across to fumaric acid is considered valid and malic acid is considered to have similar low toxicity. The rational for read across is that fumaric acid will metabolise in biological systems to malic acid. Fumaric acid is also slightly more fat soluble and is considered more likely to absorb via membranes and increase transport.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

1 306 mg/m³ air

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Guideline-similar study published in a peer-reviewed journal. The publication details and summarises results for circa 110 organic and inorganic materials for whch acute tests were completed prior to introduction of formal test guidelines. The conducting institute - Mellon Institute for Industrial Research or Carnegie-Mellon Institute of Research is a recognised unit publishing peer-reviewed data of reliable quality. For read-across justification see Section 13.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Mortality following single exposure assessed in groups of 3 female animals

GLP compliance:

no

Remarks:

Study conducted prior to establishment of GLP guidelines

Test type:

other:

Limit test:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

No data
TEST ANIMALS
- Weight at study initiation: 3-4 kg
- Diet (e.g. ad libitum): Purina rabbit chow, ad libitum

Type of coverage:

occlusive

Vehicle:

not specified

Duration of exposure:

24 hours

No. of animals per sex per dose:

3 females / group

Control animals:

not required

Details on study design:

No data

Statistics:

No data

Sex:

not specified

Dose descriptor:

LD50

Effect level:

> 20 000 mg/kg bw

Based on:

not specified

Mortality:

No mortality occurred

Clinical signs:

other: No data

Gross pathology:

No data

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

This study supports the conclusion that fumaric acid is of very low acute dermal toxicity and would not require classification for oral toxicity under EU, CLP or GHS systems.

Executive summary:

Single dose dermal toxicity of fumaric acid using female rabbits was reported as being in excess of 20000 mg/kg.

Read across to fumaric acid is considered valid and malic acid is considered to exhibit similar low toxicity. The rational for read across is that fumaric acid will metabolise in biological systems to malic acid. Fumaric acid is also slightly more fat soluble and is considered more likely to absorb via membranes and increase transport.

It is not considered valid to perform further animal tests on malic acid.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

20 000 mg/kg bw

Additional information

Information on acute toxicity are available for malic acid from a number of studies in the rat, mouse and rabbit.

Data have also been presented for fumaric acid, which may be regarded as a structural analogue of malic acid. Read across from fumaric acid to malic acid is considered valid as fumaric acid will metabolise in biological systems to malic acid. Fumaric acid is also slightly more fat soluble and is considered more likely to absorb via membranes and increase transport.

Comments on the toxicity of other caboxylic acids suggest that local irritation / corrosion can occur at high concentration and the oral and systemic dermal toxicity will be highly dependant on the choice of vehicle and concentration tested. Testing on the salts show similar low toxicity (BIBRA review 1987) to that of the acid when administered by gavage.

Justification for selection of acute toxicity – oral endpoint
Best documented of the studies available

Justification for classification or non-classification

Malic acid is concluded to have low toxicity and classification is not required according to current EU and GHS criteria.