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Administrative data

Description of key information

Three studies were available on the oral toxicity of TMAC. These studies resulted in the following LD50's:
TNO1978: LD50 = 47 mg/kg bw (conducted with 2% TMAC)
MB2007: LD50 = 55 mg/kg bw (conducted with 10% TMAC)
MB2010: LD50 = 171,9 mg/kg bw (conducted with 15% TMAC)
One dermal study is available (MB2007), which resulted in an LD50 of >200 and <500 mg/kg bw.

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:
weight of evidence
Study period:
1978
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study performed before test guidelines and GLP principles were in place. However missing information and shortcomings in description of the methods. No details on test substance (Lot/Batch number; purity).
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
GLP compliance:
no
Remarks:
Experiment was done before GLP principles were implemented.
Test type:
standard acute method
Limit test:
no
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: TNO in house breeding
- Age at study initiation: not described
- Weight at study initiation: males 197 - 352 g; female 105 - 200 g
- Fasting period before study: yes, overnight
- Housing: in groups of 5, in stainless steel cages
- Diet: ad libitum, stock diet
- Water: ad libitum, tap water
- Acclimation period: not necessary (in house breeding)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23-25C
- Humidity (%): not described
- Air changes (per hr): not described, "well-ventilated"
- Photoperiod (hrs dark / hrs light): not described

Route of administration:
oral: gavage
Vehicle:
water
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 2% v/v

MAXIMUM DOSE VOLUME APPLIED: 6.2 ml/kg bw
Doses:
single doses of 0.06, 0.072, 0.086, 0.104 and 0.124 ml/kg body weight (corresponds to 30, 36, 43, 52 and 62 mg TMAC /kg bw)
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: none performed
- Necropsy of survivors performed: yes
- Other examinations performed: no
Statistics:
The LD50 was calculated according to the method of Weil (Biometrics (1952) 249-263)
Sex:
male/female
Dose descriptor:
LD50
Effect level:
47 mg/kg bw
Based on:
other: TMAC
95% CL:
> 41 - < 50.5
Mortality:
Deaths occurred between 1 and 18 hours after dosing.
Clinical signs:
Within a few hours after treatment the rats showed sedation, clonic convulsions and dacryorrhoea. Coma was frequently observed. The survivors recovered gradually and looked quite healthy again at the end of the observation period.
Body weight:
Not recorded.
Gross pathology:
Macroscopic examination of the survivors at autopsy did not reveal any treatment-related gross alterations.

dose

mortality

Solution

ml/kg

Test substance

(50% aqueous sol.)

ml/kg

number

%

males

females

3.0

0.060

0/5

0/5

0

3.6

0.072

0/5

1/5

10

4.3

0.086

2/5

2/5

40

5.2

0.104

2/5

5/5

70

6.2

0.124

3/5

4/5

70

Interpretation of results:
highly toxic
Remarks:
Migrated information category 2 Criteria used for interpretation of results: EU
Conclusions:
In an oral toxicity study with rats in general according to OECD 401 (1987), the LD50 of a 50% aqueous solution of TMAC was found to be 0.094 ml/kg bw. This is equivalent to an LD50 of 47 mg/kg bw for pure TMAC. Therefore the substance is classified for oral toxicity in category 2 according to CLP Regulation (EC) 1272/2008.
Executive summary:

In an oral toxicity study with male and female rats in general according to OECD guideline 401 (1987), the rats were orally exposed to dilutions of a 50% aqueous solution of TMAC. Deaths occurred between 1 and 18 hours after dosing. Within a few hours after treatment the rats showed sedation, clonic convulsions and dacryorrhoea. Coma was frequently observed. The survivors recovered gradually and looked quite healthy again at the end of the observation period. The LD50 of the 50% aqueous solution of the test substance was found to be 0.094 ml/kg bw. This is equivalent to an LD50 of 47 mg/kg bw for pure TMAC. The substance is classified for oral toxicity in category 2 according to CLP Regulation (EC) 1272/2008.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LD50
Value:
47 mg/kg bw
Quality of whole database:
Three studies are available.
One study (TNO1978) was performed before test guidelines and GLP principles were in place. There is missing information and shortcomings in description of the methods: no details on test substance (Lot/Batch number; purity) were given (reliability 2).
Two reports from MB are available, conducted in 2007 and 2010, both studies have reliability 1 and were performed according to current OECD guidelines under GLP principles.

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:
2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted according to OECD 402 and GLP.
Qualifier:
according to
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Version / remarks:
dd February 24, 1987
Deviations:
yes
Remarks:
At 2 days during study, the temperature was not recorded continuously. Only 2 dose groups i.o. 3 as required. These deviations had no apparant effect on the study outcome.
GLP compliance:
yes
Test type:
standard acute method
Limit test:
no
Species:
rabbit
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Millbrook Breeding Labs, Amherst, MA, USA
- Age at study initiation: 11-13 weeks
- Weight at study initiation: 2.5-2.8 kg for males and 2.4-2.8 kg for females
- Fasting period before study: no
- Housing: individually, suspended wire cages
- Diet: fresh PMI Rabbit Chow (Diet # 5321), ad libitum
- Water: ad libitum
- Acclimation period: at least one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): "temperature controlled"
- Humidity (%): not described
- Air changes (per hr): not described
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 05/31/07 To: 07/04/07
Type of coverage:
semiocclusive
Vehicle:
water
Details on dermal exposure:
TEST SITE
- Area of exposure: dorsal area of the trunk
- % coverage: approximately 10% of the body surface
- Type of wrap if used: exposed area was covered with surgical gauze patch and torso was wrapped with plastic in a semi-occlusive manner.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes, with tap water/ distilled water
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount applied: 500/200 mg/kg
- For solids, paste formed: yes, the test article was moistened with 0.4 to 1.4 ml of distilled water to form a paste.
Duration of exposure:
24 hours
Doses:
200 or 500 mg/kg bw
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of weighing: pretest, weekly and at death
- Frequency of observations: twice daily for mortality
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs( 1,2, and 4 hours postdose and once daily for 14 days); iritation scoring: 24 hrs, 7 and 14 days post dose
Statistics:
An estimate of the LD50 was made based on the survival during the study.
Key result
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 200 - < 500 mg/kg bw
Based on:
test mat.
Mortality:
At 500 mg/kg bw, 6/10 animals died (4M + 2F). Deaths occurred within 22 hours post dose. All animals survived the 200 mg/kg bw dose.
Clinical signs:
Pre-death physical signs included lethargy and wetness of the nose/mouth area. Instances of wetness of the nose/mouth area, lethargy, few feces and diarrhea were noted in the survivors. Dermal effects were absent throughout the study at 500 mg/kg bw.
At 200 mg/kg, instances of diarrhea, few feces and soiling of the anogenital area were noted during the study. Dermal effects ranged from absent to very slight on day 1 and were absent on days 7 and 14 (only seen in 2/5 males, absent in females).
Body weight:
Body weight changes were normal.
Gross pathology:
Necropsy results of the animals that died after exposure revealed wetness of the nose/mouth area and abnormalities of the treated skin area, lungs, intestines, spleen, thymus and pancreas. Necropsy of the surviving animals revealed abnormalities of the thymus and kidneys among three of the animals; one survivor appeared normal at necropsy.
At 200 mg/kg, necropsy showed abnormalities of the kidneys in one animal. All other animals appeared normal.
Conclusions:
The dermal LD50 of the test compound was found to be >200 mg/kg but less than 500 mg/kg of body weight.
Executive summary:

An acute dermal toxicity test was performed according to current OECD guidelines and under GLP principles. Rabbits were exposed to 200 or 500 mg/kg bw. After exposure to the highest dose, 6/10 animals died. No mortality was seen after exposure to 200 mg/kg bw. Lethargy, instances of diarrhea, few feces and soiling of the anogenital area were noted during the study. Dermal effects ranged from absent to very slight on day 1 and were absent on days 7 and 14 (only seen in 2/5 males, absent in females). Changes in weight gain were absent throughout the study.

The dermal LD50 of the test compound was found to be >200 mg/kg but less than 500 mg/kg of body weight. Based on these data, the substance has to be classified for dermal toxicity in category 3 according to CLP Regulation (EC) 1272/2008.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
discriminating dose
Value:
200 mg/kg bw
Quality of whole database:
Study conducted according to OECD guideline and GLP principles.

Additional information

In an oral toxicity study (TNO1978), the rats were orally exposed to dilutions of a 50% aqueous solution of TMAC. Deaths occurred between 1 and 18 hours after dosing. Within a few hours after treatment the rats showed sedation, clonic convulsions and dacryorrhoea. Coma was frequently observed. The survivors recovered gradually and looked quite healthy again at the end of the observation period. The LD50 of the 50% aqueous solution of the test substance was found to be 0.094 ml/kg bw. This is equivalent to an LD50 of 47 mg/kg bw for pure TMAC.

A second oral toxicity study was following the up and down procedure, female rats were dosed with 17.5, 55 or 175 mg/kg bw. Predeath signs included convulsions, tremors, sagging eyelids, nose/mouth area wet, flaccid muscle tone, prostration, lethargy, spasms, ataxia and eyes closed. The deaths occurred within 24 hours of dosing. Two survivors appeared normal at necropsy, but necropsy of one surviving animal revealed abnormalities of the pancreas, kidneys and ovaries Based on these data, the LD50 of TMAC was found to be 55 mg/kg bw.

A third oral toxicity study was also conducted following the up and down procedure, 7 female rats were dosed at 300, 550 or 2000 mg/kg bw. Deaths occurred within 2 hours of dosing. Prior to death, abnormal physical signs included prostration and lethargy. Abnormal physical signs of few feces, chromorhinorrhea, lethargy and wetness of the anogenital area were noted in the survivors. Necropsy did not reveal any abnormalities in any of the rats. Based on these data, the LD50 of 15% aqueous TMAC was found to be 1146 mg/kg bw. This is equivalent to 171.9 mg/kg bw TMAC.

An acute dermal toxicity test was performed with rabbits that were exposed to 200 or 500 mg/kg bw. After exposure to the highest dose, 6/10 animals died. No mortality was seen after exposure to 200 mg/kg. Lethargy, instances of diarrhea, few feces and soiling of the anogenital area were noted during the study. Dermal effects ranged from absent to very slight on Day 1 and were absent on Days 7 and 14. Changes in weight gain were absent throughout the study.

The dermal LD50 of the substance was found to be >200 mg/kg but less than 500 mg/kg of body weight. .


Justification for selection of acute toxicity – oral endpoint
The three available studies were used in a weight of evidence approach to determine the LD50. From these studies, the worst case scenario resulted in an LD50 of 47 mg/kg bw.

Justification for selection of acute toxicity – dermal endpoint
One study available.

Justification for classification or non-classification

The oral LD50 of TMAC was found to be 47 mg/kg bw. The dermal LD50 of TMAC was found to be >200 mg/kg but less than 500 mg/kg of body weight.

Based on these results, the substance will be classified for oral toxicity in category 2 and in category 3 for acute dermal toxicity according to CLP Regulation (EC) 1272/2008.

Based on the severe clinical effects observed indicating an effect on the CNS, the substance is classified as STOT SE cat 1 according to CLP Regulation (EC) 1272/2008.