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Administrative data

Description of key information

Acute oral toxicity: LD50 (rat, male) = 660 mg a.i/kg bw (similar to EU method B.5)
Acute inhalation toxicity: no relevant route of exposure
Acute dermal toxicity: LD50 (rat) > 2000 mg a.i./kg bw (OECD guideline 402 + extrapolation from acute oral toxicity study/ toxicokinetic data)

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:
1984-08-17 to 1984-11-23
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions
Qualifier:
equivalent or similar to guideline
Guideline:
EU Method B.1 (Acute Toxicity (Oral))
Deviations:
no
GLP compliance:
no
Remarks:
At the time of the study conduct, GLP was not compulsory. However, the study was conducted in accordance with the principles of GLP.
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: Charles River, Germany
- Age at study initiation: 4–7 weeks
- Weight at study initiation: Males: 110–150 g, Females: 100–140 g
- Fasting period before study: yes, overnight
- Housing: individually
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: 7 d

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-23
- Humidity (%): 40-70
- Air changes (per hr): >10
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:
oral: gavage
Vehicle:
other: dest. water
Details on oral exposure:
VEHICLE
- Concentration in vehicle:
Group 1: 500.0 mg/mL
Group 2: 195.3 mg/mL
Group 3: 312.5 mg/mL
Group 4: 800.0 mg/mL
- Amount of vehicle (if gavage): 10 mL/kg
Doses:
Group 1: 5000 mg/kg bw
Group 2: 1953 mg/kg bw
Group 3: 3125 mg/kg bw
Group 4: 8000 mg/kg bw
(as "product by process", 20%)
No. of animals per sex per dose:
Sighting study: 4 animals per group (2 females and 2 males)
Main study: 10 animals per group (5 females and 5 males)
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Clinical signs: Observations were made within 15 and 30 minutes, 1, 2 and 4 hours after dosing and subsequently in surviving animals at least once daily throughout an observation period of 14 days.
Body weights: The body weight of each animal was recorded on the day before treatment, on the day of treatment and again seven and fourteen days after treatment.
- Necropsy of survivors performed: yes
Statistics:
Calculation of LD50 for male and female rats based on probit method of Finney (1984).
Sex:
male
Dose descriptor:
LD50
Effect level:
660 mg/kg bw
Based on:
act. ingr.
Sex:
female
Dose descriptor:
LD50
Effect level:
863.6 mg/kg bw
Based on:
act. ingr.
Sex:
male/female
Dose descriptor:
LD50
Effect level:
756.6 mg/kg bw
Based on:
act. ingr.
Sex:
male
Dose descriptor:
LD50
Effect level:
3 300 mg/kg bw
Based on:
test mat.
Sex:
female
Dose descriptor:
LD50
Effect level:
4 318 mg/kg bw
Based on:
test mat.
Sex:
male/female
Dose descriptor:
LD50
Effect level:
3 783 mg/kg bw
Based on:
test mat.
Mortality:
Mortalities occurred between two hours after dosing and day 6. There were deaths among rats dosed at 3125 mg/kg bw and at all higher dose levels. All rats receiving 8000 mg/kg bw test item died.
Clinical signs:
On the day of treatment piloerection were observed in all of the 10 test animals of all dose groups. Animals of the middle dosed groups showed increased signs of hunched posture (9/10 animals of dose level 3125 mg/kg bw; 4/10 animals of dose level 5000 mg/kg bw) and lethargy (8/10 animals of dose level 3125 mg/kg bw; 4/10 animals of dose level 5000 mg/kg bw). Changes in breathing frequency were observed in a few animals (1 to 4) of all dosed groups. All surviving animals of the middle dosed groups appeared normal on day eight after treatment.
Body weight:
All surviving rats showed bodyweight gain at the end of the observation period.
Gross pathology:
All animals of the lowest dose group showed no remarkable necropsy findings.
In the higher dosed groups the following findings were noted: congestion in liver and spleen (6 animals of dose group 8000 mg/kg bw, 3 animals of dose group 5000 mg/kg bw, and 1 animals of dose group 3125 mg/kg bw), intensive reddening of the mucosal surface of the stomach (7 animals of dose group 8000 mg/kg bw, 3 animals of dose group 5000 mg/kg bw, and 2 animals of dose group 3125 mg/kg bw), autolysis (6 animals of dose group 8000 mg/kg bw, 3 animals of dose group 5000 mg/kg bw, and 4 animals of dose group 3125 mg/kg bw). High graded hyperaemia and partially with yellow liquid filled gastrointestinal tract were noted in 2 animals of each dose level group. Overloading of stomach was observed in the dose level group 5000 mg/kg bw (1/10 animals) and in the dose level group 8000 mg/kg bw (5/10 animals).

Table A6.1.1-1:Acute toxicity in rats.

Group

Dose [mg/kg bw]*

Number of dead/ number of investigated

Time of death

Observations

Males

Females

Total

1

5000

3/5

3/5

6/10

Day 1–5

Piloerection, hunched posture, lethargy, eye lids half-closed, eye lids nearly closed, eye lids closed, heavy breathing, loamy coloured anal and genital tract, salivation, aggression

2

1953

0/5

0/5

0/10

Piloerection, hunched posture, lethargy, eye lids half-closed, increased breathing, emaciation

3

3125

4/5

1/5

5/10

Day 2–6

Hunched posture, lethargy, piloerection, eye lids half-closed, eye lids nearly closed, eye lids closed, increased breathing, heavy breathing, lacrimation, brown coloured anal and genital tract

4

8000

5/5

5/5

10/10

Day 1–3

Piloerection, lethargy, hunched posture, prone position, eye lids closed, eye lids half-closed, increased breathing

LD50 value [mg/kg bw]

 

3300

4318

3783

 

 

*) based on test substance as manufactured (20% aqueous solution)

Interpretation of results:
other: Category 4
Remarks:
Criteria used for interpretation of results: other: CLP, EU GHS (Regulation (EC) No 1272/2008)
Conclusions:
The oral LD50 (rat, male) of DOPA-Glycinate was determined to be 660 mg a.i/kg bw.
Executive summary:

The acute oral toxicity of DOPA-Glycinate (20% aqueous solution) was tested in Sprague Dawley rats. 4 Groups of 10 animals, 5 male and 5 female rats, received single oral doses of 1953, 3125, 5000 or 8000 mg/kg bw of the test item by gavage. Animals were then observed for 14 days. Although not a guideline study, the method used was consistent to method B.1 (92/69/EEC) in all important aspects.

Death was noted between two hours after dosing and day 6. There were deaths among rats dosed with 3125 mg/kg bw and at all higher dose levels. All rats receiving 8000 mg/kg bw died. On the day of treatment piloerection were observed in all of the 10 test animals of all dose groups. Further frequently occurred symptoms were hunched posture and lethargy in animals of the middle dosed groups. All surviving animals of the middle dosed groups (3125 and 5000 mg/kg bw) appeared normally on day eight after treatment.

The LD50 in terms of test material (20% aqueous solution) was calculated at 3300 mg/kg bw for males, 4318 mg/kg bw for females and 3783 mg/kg bw for combined sexes.

These values correspond to 660 mg a.i./kg bw for males, 863.6 mg a.i./kg bw for females and 756.6 mg a.i./kg bw for combined sexes.

According to the criteria laid down in Regulation (EC) No 1272/2008, DOPA-Glycinate is classified for Acute toxicity, Category 4.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed
Dose descriptor:
LD50
Value:
660 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 000 mg/kg bw

Additional information

Acute oral Toxicity

The acute oral toxicity of DOPA-Glycinate (20% aqueous solution) was tested in Sprague Dawley rats. 4 Groups of 10 animals, 5 male and 5 female rats, received single oral doses of 1953, 3125, 5000 or 8000 mg/kg bw of the test item by gavage. Animals were then observed for 14 days. Although not a guideline study, the method used was consistent to method B.1 (92/69/EEC) in all important aspects. Death was noted between two hours after dosing and day 6. There were deaths among rats dosed with 3125 mg/kg bw and at all higher dose levels. All rats receiving 8000 mg/kg bw died. On the day of treatment piloerection were observed in all of the 10 test animals of all dose groups. Further frequently occurred symptoms were hunched posture and lethargy in animals of the middle dosed groups. All surviving animals of the middle dosed groups (3125 and 5000 mg/kg bw) appeared normally on day eight after treatment.

The LD50 in terms of test material (20% aqueous solution) was calculated at 3300 mg/kg bw for males, 4318 mg/kg bw for females and 3783 mg/kg bw for combined sexes.

These values correspond to 660 mg a.i./kg bw for males, 863.6 mg a.i./kg bw for females and 756.6 mg a.i./kg bw for combined sexes.

This is supported by the following data:

The acute oral toxicity of DOPA-Glycinate (99.4% a.i.) was tested in female Wistar rats according to EC method B.1 tris (1996) and OECD guideline 423 (2001). Two groups of 3 female rats received 300 mg/kg bw of test substance by gavage. After exposure the animals were observed for clinical signs, mortality, body weight and gross pathology for 14 days.

One female was found dead on day 1, 27 hours after dosing, showing sluggishness, encrusted nose, piloerection and a soiled fur prior to its death. No other mortality was observed during the study.

Clinical signs generally observed after dosing consisted of sluggishness, vocalization, encrustated nose and piloerection.

Over the 14 day study period the surviving animals gained weight, apart from a light reduction in body weight on day 3. The one animal found dead showed body weight loss.

Examination at necropsy of the animals did not reveal distinct treatment-related gross alterations.

Since 5 out of 6 animals survived the 300 mg/kg bw application of the test substance, the LD50 is estimated to be between 300 and 2000 mg/kg bw. A 2000 mg/kg bw dose level was not examined because of the corrosivity of the test material.

 

Acute inhalation toxicity

The active substance is a 20% aqueous solution of the active matter (“product by process”), from which the active ingredient is not volatile (vapour pressure < 1.9 × 10–4 Pa). The active substance is neither a powder nor is it to be included in powdery preparations. Furthermore, the substance is not intended to be applied in a manner leading to generation of aerosols, particles or droplets in the inhalable size range (MMAD < 50 µm). Therefore, the generation of data on the inhalation toxicity is not considered to be required.

Acute dermal toxicity

The acute dermal toxicity of DOPA-Glycinate (20% aqueous solution) was tested in Sprague-Dawley rats according to OECD guideline 402 (1987). A dose of 2000 mg/kg bw test item was applied once by the cutaneous route. No deviations from the methods prescribed by the guideline were reported.

Administration of the test material caused no mortality among the test animals. Therefore, the LD50 was established above the limit dose of 2000 mg/kg bw in terms of test item as manufactured, corresponding to 400 mg a.i./kg bw.

Although the substance has only been tested at 400 mg a.i./kg bw, the consideration of all available data on acute dermal toxicity, acute oral toxicity, toxicokinetics and dermal penetration leads to the conclusion, that the dermal LD50 will be > 2000 mg a.i./kg bw and thus no classification for acute dermal toxicity will be required.

For classification and labelling purposes, the dermal LD50 has been extrapolated from the oral LD50 based on experimental toxikokinetic data for both routes of exposure.

The oral LD50 was determined to be 660 mg/a.i./kg bw.

In an ADME study in rat according to OECD Guideline 417, the oral absorption of DOPA-Glycinate was determined to be 34%.

The Guidance on Information requirements and Chemical Safety Assessment, R.7c (Nov. 2012) states: “In practice, an adjustment in oral toxicity factor (to account for absorbed dose in the dermal exposure pathway) is recommended when the following conditions are met: (1) the toxicity value derived from the critical study is based on an administered dose (e.g., delivery in diet or by gavage) in its study design; (2) a scientifically defensible database demonstrates that the GI absorption of the chemical in question, from a medium (e.g., water, feed) similar to the one employed in the critical study, is significantly less than 100% (e.g., <50%). A cut-off of 50% GI absorption is recommended to reflect the intrinsic variability in the analysis of absorption studies. Thus, this cut-off level obviates the need to make comparatively small adjustments in the toxicity value that would otherwise impart on the process a level of accuracy that is not supported by the scientific literature.”

Thus, 50% oral absorption should be assumed.

The dermal absorption was investigated in an in vitro study with human skin according to OECD Guideline 428. The systemically available dose was determined to be 0.6±0.6% of the applied substance in accordance with the definition given in the Guidance on Information requirements and chemical safety assessment, R.7c.

Based on these data, the dermal LD50 of DOPA-Glycinate can be assumed to be >2000 mg a.i./kg bw.

There are no data gaps in acute toxicity. Even though there is no information on acute toxicity in humans, there is no reason to believe that the results obtained in experimental animals would not be relevant for human health.


Justification for selection of acute toxicity – oral endpoint
comparable to EC guideline study

Justification for selection of acute toxicity – inhalation endpoint
Inhalation is no relevant route of exposure.

Justification for selection of acute toxicity – dermal endpoint
OECD guideline study; however no higher dose levels have been tested (2000 mg test material/kg bw ), corresponding to 400 mg a.i./kg bw

Justification for classification or non-classification

According to the criteria laid down in Regulation (EC) No 1272/2008, DOPA-Glycinate is classified with Hazard Category 4 for acute oral toxicity (H302: harmful if swallowed). No classification for acute dermal toxicity is required.

According to the requirements specified by Directive 67/548/EC, DOPA-Glycinate requires classification for acute oral toxicity (R22:Harmful if swallowed).