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Administrative data

Description of key information

- study conducted according to OECD guideline 423, acute toxic class method, 6 female Wistar rats were exposed to a single dose of 2000 mg/kg bw Tetrahydrofolic acid in two steps and observed for 14 days, LD50 cut-off = 5000 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:
key study
Study period:
2017-12-18 to 2018-03-22
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Version / remarks:
adopted 17 December, 2001
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)
Version / remarks:
30 May, 2008
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.1100 (Acute Oral Toxicity)
Version / remarks:
December 2002
Deviations:
no
GLP compliance:
yes (incl. certificate)
Test type:
acute toxic class method
Limit test:
yes
Species:
rat
Strain:
Wistar
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 8-9 weeks
- Weight at study initiation: Step 1: animals no. 1-3: 148 – 164 g; Step 2: animals no. 4-6: 153 – 166 g
- Fasting period before study: Prior to the administration food was withheld from the test animals for 16 to 19 hours (access to water was permitted).
- Housing: The animals were kept in groups in IVC cages, type III H, polysulphone cages on Altromin saw fibre bedding
- Diet (e.g. ad libitum): Ad libitum, Altromin 1324 maintenance diet for rats and mice
- Water (e.g. ad libitum): Ad libitum, tap water, sulphur acidified to a pH value of approximately 2.8 (drinking water, municipal residue control, microbiological controls at regular intervals)
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 55 ± 10
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:
oral: gavage
Vehicle:
water
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 200 mg/mL
- Amount of vehicle (if gavage): 10 mL


MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg


CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: It is the principle of the acute toxic class method that, based on a stepwise procedure with the use of a minimum number of animals per step, sufficient information is obtained on the acute toxicity of the test item to enable its classification. The item is tested using a stepwise procedure with up to four fixed doses. Absence or presence of compound-related mortality of the animals dosed at one step will determine the next step
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
3 per step
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: All animals were examined for clinical signs several times on the day of dosing and once daily until the end of the observation period. Their body weights were recorded on day 1 (prior to the administration) and on days 8 and 15. All animals were necropsied and examined macroscopically.
- Other examinations performed: clinical signs, body weight
Key result
Sex:
female
Dose descriptor:
LD50 cut-off
Effect level:
5 000 mg/kg bw
Based on:
test mat.
Key result
Sex:
female
Dose descriptor:
LD50
Remarks:
experimental
Effect level:
> 2 000
Based on:
test mat.
Remarks on result:
not determinable due to absence of adverse toxic effects
Mortality:
no mortality occurred
Clinical signs:
The most relevant clinical findings in the animals treated with the test item at a dose of 2000 mg/kg bw were reduced spontaneous activity, piloerection, hunched posture and half eyelid-closure. All symptoms recovered within up to 2 days post-dose.
Body weight:
Throughout the 14-day observation period, the weight gain of the animals was within the normal range of variation for this strain.
Gross pathology:
At necropsy, no treatment-related macroscopic findings were observed in any animal of any step.

Table 1: Clinical signs - Individual data (Step 1)

Step

Animal No. / Sex

Starting Dose (mg/kg bw)

Timepoint

Observations

1

1 / Female

2000

0 – 30 min

nsf

30 – 60 min

Slightly reduced spontaneous activity, slight piloerection, half eyelid-closure

60 – 240 min

Slightly reduced spontaneous activity, slight piloerection, hunched posture

240 min - d 2

Slightly reduced spontaneous activity, slight piloerection

d 2 – d 15

nsf

0 – 30 min

nsf

2 / Female

30 – 60 min

Slightly reduced spontaneous activity, slight piloerection, half eyelid-closure

60 – 240 min

Slightly reduced spontaneous activity, slight piloerection, hunched posture

240 min - d 2

Slightly reduced spontaneous activity, slight piloerection

d 2 – d 15

nsf

0 – 30 min

nsf

3 / Female

30 – 60 min

Slightly reduced spontaneous activity, moderate piloerection, half eyelid-closure

60 – 120 min

Slightly reduced spontaneous activity, hunched posture, moderate piloerection, half eyelid-closure

120 – 240 min

Slightly reduced spontaneous activity, hunched posture, slight piloerection

240 min – d 2

Slightly reduced spontaneous activity, slight piloerection

d 2 – d 15

nsf

Table 2: Clinical signs - Individual data (Step 2)

Step

Animal No. / Sex

Starting Dose (mg/kg bw)

Timepoint

Observations

2

4 / Female

2000

0 – 60 min

nsf

60 – 180 min

Slightly reduced spontaneous activity, hunched posture, slight piloerection

180 - 240 min

Slight piloerection, hunched posture

240 min - d 2

Slightly reduced spontaneous activity, hunched posture, slight piloerection

d 2 – d 15

nsf

5 / Female

0 – 60 min

nsf

60 – 180 min

Slightly reduced spontaneous activity, hunched posture, slight piloerection

180 – 240 min

Hunched posture, slight piloerection

240 min - d 2

Slightly reduced spontaneous activity, hunched posture, slight piloerection

d 2 – d 15

nsf

6 / Female

0 – 60 min

nsf

60 – 180 min

Slightly reduced spontaneous activity, hunched posture, slight piloerection

180 – 240 min

Hunched posture, slight piloerection

240 min - d 2

Slightly reduced spontaneous activity, hunched posture, slight piloerection

d 2 – d 15

nsf

Interpretation of results:
GHS criteria not met
Conclusions:
Under the conditions of the present study, a single oral application of the test item Tetrahydrofolic acid (THFA) to rats at a dose of 2000 mg/kg body weight was associated with signs of toxicity but no mortality.
The median lethal dose of Tetrahydrofolic acid (THFA) after a single oral administration to female rats, observed over a period of 14 days is:
LD50 cut-off (rat): 5000 mg/ kg bw
Thus, the substance does not need to be classified according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System for Calssification and Labelling of Chemicals (GHS).
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
discriminating dose
Value:
2 000 mg/kg bw
Quality of whole database:
The study was conducted according to OECD guidelines and GLP, thus, the study is of high quality.

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Under the conditions of the present study, a single oral application of the test item Tetrahydrofolic acid (THFA) to rats at a dose of 2000 mg/kg body weight was associated with signs of toxicity but no mortality. The most relevant clinical findings in the animals treated with the test item at a dose of 2000 mg/kg bw were reduced spontaneous activity, piloerection, hunched posture and half eyelid-closure. All symptoms recovered within up to 2 days post-dose.

The median lethal dose of Tetrahydrofolic acid (THFA) after a single oral administration to female rats, observed over a period of 14 days is:

LD50 cut-off (rat): 5000 mg/ kg bw

Justification for classification or non-classification

Based on the available data the substance does not need to be classified according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System for Calssification and Labelling of Chemicals (GHS).