4,4'-methylenedianiline

Endpoint summary

Description of key information

Acute oral LD50 in rats 444 mg/kg bw, in cats and dogs between 50-100 mg/kg bw. 

Acute dermal LD50 in rats >2000 mg/kg bw (no assay in other species available). 

No mortality was observed in rats and cats with highest technically feasible and respirable inhalation atmosphere.

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:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

BASF-Test: Test substance was applied by gavage in a 1.25 - 2.5% aqueous traganth suspension. Mortality, clinical signs, and pathology of animals was investigated. Additionally, methemoglobin and Heinz bodies were investigated.

GLP compliance:

no

Test type:

standard acute method

Species:

cat

Strain:

not specified

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: see table 1

Route of administration:

oral: gavage

Vehicle:

other: aqueous traganth suspension

Details on oral exposure:

1.25 - 2.5% aqueous traganth suspension were used.

Doses:

10, 25, 50, 100, 200, and 400 mg/kg bw

No. of animals per sex per dose:

10: 1 male; 2 female
25: 0 male; 3 female
50: 1 male; 2 female
100: 6 male; 5 female
200: 2 male; 5 female
400: 1 male; 1 female

Control animals:

no

Details on study design:

One application of 1.25 - 2.5% aqueous tragacanth suspension were used.

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 50 mg/kg bw

Based on:

test mat.

Mortality:

10: 0/3
25: 1/3; 1 female after 6 days
50: 0/3
100: 7/11; 3 male; 4 female
200: 6/7; 1 male; 5 female
400: 2/2; 1 male; 1 female

Clinical signs:

other: After treatment animals were atonic, staggering and mostly vomitting. Animals had mydriasis, showed no pupil reaction to light and had a reduced corneal sensibility. The animals were amblyopic or suffered from blindness. These chacteristics could be obse

Gross pathology:

Hepatotoxicity:
One day after treatment damage of the liver was observed with a disturbed excretion of bromosulphthaleine. Also the activity of serume glutamate-pyruvate-transaminase was disturbed. High bilirubin levels in urin and icterus were observed. Damage of liver functions seemed to be reversible, but occured beginning with 10 mg/kg bw.
Kidney:
High urea levels were observed in blood, accompanied with high protein, leukocytes, erythrocytes levels in urine. Additionally kidney epithelial cells and granulated cylinders were verified in urine. These characteristics also occured from the dose level 10 mg/kg bw.

Other findings:

Ophthamologigal reevaluation revealed strong mydriasis with no or weak reactivity toward light pulses. Blindeness was diagnosed by unsecure motion of the animals. Animals partly exhibited a spastic constriction of arteries (diameter decreased to approx. half) 43 and 22 days following application of the test substance.

Table 1: Body weights of cats (at study initiation and determination), Met-Hb levels (in %), Heinz bodies (% erythrocytes) and mortalities (day after application).

Dose (mg/kg)	Bodyweight (kg)	Bodyweight (kg)	Methaemoglobine (%)	Dead after days	Killed after day	Heinz bodies (%)	characteristic intoxication
	study init.	end det.
10	3.3	3.2	-	-	-	15	-
	2.7	2.6	-	-	-	8	-
	2.8	2.6	-	-	-	9	-
25	2.5	2.5	-	-	29	28	mydriasis up to blindness, nephrosis
	2.3	2.0	-	-	31	30	mydriasis up to blindness, mild liver and kidney damage
	2.6	2.2	-	6		24	mydriasis up to blindness, mild ikterus
50	2.6	2.4	-	-	54	47	mydriasis up to blindness, mild hepatitis and nephrosis
	2.2	2.0	9	-	54	41	mydriasis up to blindness, hepatitis
	2.2	2.1	11	-	43	76	mydriasis up to blindness
100	2.5	2.2	-	-	-	-	mydriasis up to blindness, ikterus
	3.3	3.1	12	5		14 -73	mydriasis up to blindness, ikterus, liver and kidney damage
	2.3	2.2	-	4		-	mydriasis up to blindness (?), ikterus, mild kidney damage
	2.5	2.3	-	2		-	mydriasis up to blindness, kidney damage
	3.9	3.9	13	2		27 -67	mydriasis up to blindness, mild ikterus, mild liver and kidney damage
	3.6	3.0	11	-	71	26 -45	mydriasis up to blindness, nephrosis
	3.1	2.3	-	-	71	10 -94	mydriasis up to blindness, nephritis and nephrosis
	3.3	2.9	-	-	98	35 -46	mydriasis up to blindness, nephritis
	2.5	2.3	17	2		35 -46	mydriasis up to blindness, kidney damage
	2.9	2.7	-	1		-	mydriasis up to blindness, mild ikterus,
	2.6	2.4	11	3		18 -41	mydriasis up to blindness, mild ikterus, liver and kidney damage
200	2.9	2.6	-	1		-	mydriasis up to blindness, ikterus, kidney damage
	1.7	1.6	15	3		71	mydriasis up to blindness, severe ikterus, liver and kidney damage
	2.9	2.4	-	2		-	mydriasis up to blindness, mild ikterus, kidney damage
	3.6	3.1	-	-	-	12 -83	mydriasis up to blindness
	2.8	2.8	-	1		-	mydriasis,
	3.3	3.0	-	2		-	mydriasis up to blindness,
	2.8	2.6	-	4		-	mydriasis up to blindness, ikterus, liver/kidney damage
400	3.5	3.2	-	2		-	mydriasis,
	2.7	2.7	-	3		6 -24	mydriasis, ikterus, liver/kidney damage

Interpretation of results:

Category 3 based on GHS criteria

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

Body weight was determined only before the start of the study

Principles of method if other than guideline:

BASF-TEST: Young adult laboratory rats were purchased from breeder. Several groups of 5 rats per sex and dose were treated simultaneously by gavage with preparations of the test substance in a suitable vehicle. The concentrations of these preparations were used to achieve comparable volumes per kg body weight. Group-wise documentation of clinical signs was performed over the 14 day study period. Body weight was determined before the start of the study only, as it was needed for determination of dose.

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Purity: >= 99%

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: SPF-breed: Wiga, Sulzfeld, Germany
- Weight at study initiation: male 195 g/ female 170 g
- Diet: Altromin-R, Lage, Germany, ad libitum
- Water: ad libitum

Route of administration:

oral: gavage

Vehicle:

CMC (carboxymethyl cellulose)

Details on oral exposure:

4% suspension (W/V) in 0.5% carboxymethyl cellulose

Doses:

250, 400, 500, 640 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Mortality: after 1, 24, and 48 hours and after 7 and 14 days.
- Duration of observation period following administration: 14 days
- Necropsy of survivors performed: yes

Statistics:

Determination of LD50 according to Litchfield and Wilcoxon

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

444 mg/kg bw

95% CL:

398 - 495

Mortality:

No mortalities were observed at 250 mg/kg bw.
At 400 mg/kg bw mortalities were observed 48 h after application.
At the 500 - 640 mg/kg bw mortalities were observed within the first 24 h (see table 1).

Clinical signs:

other: 400 - 640 mg/kg bw: - apathy - ataxia - abdominal position - dyspnea - after 5-7 days disappearance of clinical signs 250 mg/kg bw: - slight apathy, at day 2 no findings

Gross pathology:

Animals which died:
- acute, obstructive hyperaemia, acute dilation of the heart, slight oedema of the lungs, hydrothorax and bloody ulceration of the stomach

Sacrificed rats at 400-500 mg/kg bw.:
-pinhead-sized, grey, and in part, aggregating bodies in the liver, and splenomegaly.

Sacrificed rats at 250 mg/kg bw.:
- no pathological effects

Table 1: Mortality of animals after treatment

	250 mg/kg bw		400 mg/kg bw		500 mg/kg bw		640 mg/kg bw
	male	female	male	female	male	female	male	female
1 h	0/5	0/5	0/5	0/5	0/5	0/5	0/5	0/5
1 d	0/5	0/5	0/5	0/5	1/5	3/5	5/5	5/5
2 d	0/5	0/5	0/5	1/5	2/5	5/5	5/5	5/5
7 d	0/5	0/5	0/5	2/5	3/5	5/5	5/5	5/5
14 d	0/5	0/5	0/5	2/5	3/5	5/5	5/5	5/5

Interpretation of results:

Category 4 based on GHS criteria

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Principles of method if other than guideline:

Male and female Sprague-Dawley rats were exposed to a dust/aerosol of 0.46 mg/L phenylbase for 6 h. Animals were observed for 7 or 14 days for mortality, clinical signs and body weight.

GLP compliance:

no

Test type:

standard acute method

Limit test:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Purity: 98 %

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Weight: male 235 g (195-275 g); female 175 g (157-200 g)
Diet: Altromin-R (Altrogge), tab water ad libitum.
Housing: 2/3 animals per cage.

Route of administration:

inhalation: dust

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

Substance was pulverised and 5% talcum was added. Substance was nebulized by an equipment according to Wright (1950). Exposition of rats was performed according to Kimmerle (1963). Air stream 1000 L per hour.
Gravimetric determination of test substance concentration in exposure atmosphere: sampling using membrane filters (0.3 µm pore diameter), determination of particle size distribution using a cascade impactor (Modell CS-6, Scientific Advances).

Analytical verification of test atmosphere concentrations:

yes

Remarks:

gravimetrically

Duration of exposure:

6 h

Concentrations:

0.46 mg/L

No. of animals per sex per dose:

10

Control animals:

yes

Details on study design:

Observations:
Body weight: twice a week
Clinical symptoms: daily
Mortality: daily
Clinical chemistry: total protein, total lipid, bilirubin, GOT (glutamate-oxalacetate-transaminase), GPT (glutamate-pyruvate-transaminase), AP (alkaline phosphatase), plasma-cholinesterase
Heamatology and urinalysis.

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 0.46 mg/L air

Exp. duration:

6 h

Mortality:

No mortality occurred.

Clinical signs:

other: Animals were in a good physical state.

Body weight:

No influence of exposure on body weight was observed.

Gross pathology:

no data,

Other findings:

Total lipid, bilirubin, GOT and AP levels were increased. Total protein and plasma-cholinesterase leves were decreased. Additionally an increase of segmented leukocytes was observed. Effects were observed 24-48h following application of the test substance in both sexes and were reversible within the 7-14 day observation period.

Result of test atmosphere analysis:
82% of particles were determined to be <8 µm therefore respirable

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

Noakes, D.N. and Sanderson, D.M.: A Method for Determining the Dermal Toxicity of Pesticides. Brit. J. Industr. Med. 26,59 (1969).

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Purity: >98 %

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: SPF-breed, Wiga, Sulzfeld, Germany
- Weight at study initiation: 155 g
- Diet: Altromin-R, Lage, Germany, ad libitum
- Water: ad libitum

Type of coverage:

semiocclusive

Vehicle:

other: water or DMSO

Details on dermal exposure:

TEST SITE
shaved skin of back- and side flank, under semiocclusive cover, permeable to air.
- Area of exposure: 50 cm²

REMOVAL OF TEST SUBSTANCE
- Washing: no data

TEST MATERIAL
- Concentration: 50%

Duration of exposure:

24 h

Doses:

Aqueous solution: 1000 mg/kg and 2500 mg/kg bw
DMSO solution: 500, 1000, 1250, 2000, 2500 mg/kg bw

No. of animals per sex per dose:

10

Control animals:

not specified

Details on study design:

- Duration of observation period following administration: 14 days
- Necropsy of survivors performed: yes

Statistics:

Litchfield and Wilcoxon

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

2 080 mg/kg bw

95% CL:

ca. 1 631 - ca. 2 652

Remarks on result:

other: 50% DMSO solution

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 500 mg/kg bw

Remarks on result:

other: 50% aqueous solution, no mortalities

Mortality:

50% DMSO solution: at 1000 mg/kg bw and higher, animals started to die during the first week (see table 1).
50% aqueous solution: no mortalities

Clinical signs:

other: 50% DMSO solution: Animals at all doses displayed marked apathy, hyperchromodacryorrhea, and intensely stained yellow urine. At the dose levels of 500-2000 mg/kg bw, poisoning symptoms were no longer observed 6-9 days after the beginning of the test. A

Gross pathology:

50% DMSO solution: animals which died, and some of those sacrificed after 14 days, exhibited a bright, clay-coloured to yellowish colour change of the liver parenchyma. In the case of the 2500 mg/kg bw dose group, some of the 10 animals which died displayed an extreme, general jaundice, and some displayed a slimy to bloody enteritis, as well as bleeding stomach ulcers.
50% aqueous solution: no effects

Table 1: Mortalities after application of 50% MDA in DMSO

	500 mg/kg bw		1000 mg/kg bw		1250 mg/kg bw		2000 mg/kg bw		2500 mg/kg bw
	male	female	male	female	male	female	male	female	male	female
1 h	0/10	0/10	0/10	0/10	0/10	0/10	0/10	0/10	0/10	0/10
1 d	0/10	0/10	0/10	0/10	0/10	0/10	0/10	0/10	0/10	0/10
2 d	0/10	0/10	0/10	0/10	0/10	0/10	0/10	0/10	0/10	0/10
7 d	0/10	0/10	0/10	5/10	0/10	0/10	2/10	9/10	3/10	7/10
14 d	0/10	0/10	0/10	5/10	0/10	0/10	2/10	9/10	3/10	7/10

Interpretation of results:

GHS criteria not met

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 080 mg/kg bw

Additional information

Acute oral exposure:

The key study describing the oral toxicity of pure MDA in rats, resulted in a LD50 of 444 mg/kg bw (BASF, 1975). At a starting dose of 250 mg/kg bw, no mortalities or pathological effects have been observed. In a supporting study in rats similar LD50 values were determined, reaching from 350 to 480 mg/kg bw (Bayer AG, 1974). Damage to the liver and kidneys has been reported to be the most prominent toxic effect in rats.

 

Orally administered MDA has shown to induce severe changes in the liver of male Sprague-Dawley rats with a threshold of toxicity between 25 and 75 mg/kg. MDA caused changes in markers for liver injury, including serum ALT, bile flow, serum bilirubin concentration, GGT activity, and liver weight. Liver sections of 100 mg/kg bw animals exhibited multifocal lesions consisting of hepatocellular necrosis with hemorrhage and moderate infiltration in neutrophils (Bailie et al., 1993).

 

Cats and dogs are more sensitive to MDA exposure. After treatment with 100 mg/kg bw 7/11 cats and 3/3 dogs died. MDA induced ophthalmologic damage and damage of the liver and kidney beginning with 10 mg/kg bw in cats and 50 mg/kg bw in dogs (lowest doses tested). Mortality in both species occurred due to organs disorder (BASF, 1961). Methemoglobin (MetHb) levels were moderately elevated in cats (up to 17% with a dose of 100 mg/kg bw). Regarding the ability of MetHb-formation the cat was identified as the species most similar to human. Therefore a slight ability for MetHb in humans has to be expected, but no classification regarding effects on the hematopoetic system is indicated. Retinal damage was reported in surviving cats.

Supplementary information is available from the following studies:

BASF (1965): LD50 in male/female rats = 547 mg/kg (K2)

BASF (1958): LD50 in rats = 900 mg/kg, sex unspecified; LD50 in mice = 100 mg/kg, sex unspecified (K2)

Dow (1954): LD100 in rats = 252 mg/kg, sex unspecified, but only 2 animals per dose level. LD0 = 126 mg/kg (K4)

Schmidt et al. (1974): LD50 in rats = 355 mg/kg in males, 475 mg/kg in females (K4); LD50 in rabbits = 620 mg/kg, sex unspecified; LD50 guinea pig = 260 mg/kg; mouse = 745 mg/kg, sex unspecified

Pludro et al. (1969): LD50 in rats = 830 mg/kg, sex unspecified (K4)

Schmidt et al. (1981): No LD50 determined, assessment of liver toxicity after oral administration in rats. (K4)

Disregarded oral toxicity studies:

BASF 1958: Acute oral toxicity assessed in rats and mice, but a vehicle with known acute oral toxicity was used. Thus, the study is considered unreliable.

 

Acute dermal exposure:

Acute mortality on the dermal route of exposure was highly dependent on the solute of the tests substance (DMSO or water) and the sex of the animal. In the key study MDA was applied as a 50% aqueous solution as well as a 50% DMSO solution (BASF, 1976). While application of 2500 mg/kg bw MDA as a 50% aqueous solution caused no mortalities, 1000 mg/kg bw MDA as a 50% solution in DMSO killed 5 out of 10 female rats within 7 days. Male rats were not affected by treatment with 1000 mg/kg bw MDA in DMSO. A dose as high as 2000 mg/kg needed to be applied in order to kill male animals. Mortality increased dose dependently, resulting in an acute dermal LD50 value of 2080 mg/kg bw, with females being more susceptive than males. Apathy, hyperchromodacryorrhea, and jaundice as clinical signs of systemic toxicity have been observed in all treatment groups.

In another acute dermal toxicity, MDA was similarly applied as 3 - 4 mL aqueous or DMSO formulation. No mortalities were observed applying aqueous solutions of MDA (LD50 >1000 mg/kg, highest concentration tested) in both sexes, and in males treated with MDA in DMSO. Female rats were more sensitive to MDA in DMSO solution resulting in a LD50 of 750-1500 mg/kg (Bayer AG, 1976).

A study by BASF (1961) was disregarded because the test system was not in line with any estalblished guidelines and was thus not suitable to make a classification decision (skin was submerged in test substance for varying durations).

 

Acute inhalation exposure:

After exposure of rats for 6 h with 0.46 mg/L MDA no mortality occurred and animals were in good condition (BASF, 1977). The same experimental design was used for an inhalation study in cats and also no mortalities occurred during a 6 h exposure with 0.1 mg/L MDA. However, one animal showed salivation and 2 animals vomited during exposure. All animals in this study showed yellowish sclera and conjunctiva which was reversible after 14 days in 5/6 animals (BASF, 1977). In all tests gravimetrical determination of the particle size distribution was performed, showing that most of the dust particles were within the respirable fraction.

Supporting data was generated in a non-guideline study by Ciba-Geigy (1976), in which Tif RAIf (SPF) rats were exposed to MDA dust at the highest technically achievable concentration of 0.837 ± 0.191 mg/L for four hours. No mortality was observed. Clinical signs including exophthalmos, tremors, curved body position and ruffled fur were observed; however, the animals recovered within 2 days.

Two studies (BASF, 1954, and Dow, 1971) were disregarded due to substantial methodological deficiencies (no analysis of exposure atmospere, unsuitable test system).

 

 

Human exposure:

Acute intoxication of humans with MDA is reported after oral, dermal and inhalation exposure, leading to jaundice. In addition to acute hepatic illness, in some cases myocardial effects and persistent retinal damage were reported.

  

Conclusions

The available animal data would trigger classifications as toxic after acute oral exposure (cat. 3) and harmful in contact with skin (cat. 4) according to Regulation 1272/2008 (CLP).

It must be noted, however, that considerable dermal toxicity was only observed in presence of a solvent which can act as a carrier (DMSO).

Based on the animal data available for acute inhalation toxicity no classification is warranted, since no severe signs of toxicity or mortality were reported.

Due to severe liver toxicity of the substance at low dose levels (between 25 - 75 mg/kg), the test substance should be classified as a specific target toxicant cat 1 (STOT SE cat 1) based on CLP standards.

Taking into account that rodents may not represent the adequate model organism to predict acute toxicity of this substance to humans, human observations after several cases of acute poisoning at the workplace, and of consumers in 1965 (“Epping Jaundice”) need to be considered for classification. Since the substance is readily absorbed through the skin and the mucosa of the respiratory tract, classification as H370 (STOT SE cat 1, causes damage to the liver on all routes of exposure) was agreed on the CMR Working Group Meeting, 7.-9. October 1998.

Justification for classification or non-classification

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. Regarding acute oral toxicity, cats and dogs are more sensitive than rats with an LD50 between 50 -100 mg/kg. Considerable dermal toxicity was observed only if the solvent DMSO was used, which acts as a carrier. Therefore, no classification for acute dermal toxicity is proposed. Although the cut-off limits for acute inhalative toxicity according to regulation 1272/2008/EC were not exceeded, the highest technically feasible concentrations did not cause mortalities. No classification for acute inhalative toxicity is proposed. For all exposure pathways irreversible liver and retina effects were observed.

In summary, the substance needs to be classified and labelled for acute toxicity as acute tox 3 (H301, toxic if swallowed) and as STOT SE cat 1 (H370, causes damage to the liver on all routes of exposure) under Regulation (EC) No 1272/2008, as amended for the tenth time in Regulation (EU) No 2017/776.