2-nitro-4-(trifluoromethyl)benzonitrile

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

28 Feb - 27 Jun 2019

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Version / remarks:

adopted 25 Jun 2018

Deviations:

yes

Remarks:

- no ED-relevant endpoints examined

GLP compliance:

yes

Remarks:

The test complied with the Principles of Good Laboratory Practices (GLP) of the Certification and Accreditation Administration of the People’s Republic of China (2013 revised edition).

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-nitro-4-(trifluoromethyl)benzonitrile

EC Number:

212-298-1

EC Name:

2-nitro-4-(trifluoromethyl)benzonitrile

Cas Number:

778-94-9

Molecular formula:

C8H3F3N2O2

IUPAC Name:

2-nitro-4-(trifluoromethyl)benzonitrile

Test animals

Species:

rat

Strain:

Sprague-Dawley

Remarks:

SPF grade

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Liaoning Changsheng Biotechnology Co., Ltd., Liaoning, China
- Age at study initiation: 12 weeks
- Weight at study initiation: range (males/females) 288.35 - 292.97 at Day 0
- Fasting period before study: no
- Housing: Animals were housed in pairs during acclimatization period, and at a ratio 2 : 1 (female : male) during the overnight mating period. After impregnation, the animals were caged individually in rat breeding boxes (L 46.0 cm x W 31.5 cm x H 20.0 cm). Animal litter was corn cob litter (Liaoning Changsheng Biotechnology Co., Ltd., Liaoning, China). The litter was replaced at least once weekly.
- Diet: SPF rat/mouse breeding feed (Liaoning Changsheng Biotechnology Co., Ltd., Liaoning, China); ad libitum
- Water: grade-one reverse osmosis water (Liaoning Qianyi Testing and Evaluation Technology Development Co., Ltd., Liaoning, China); ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.00 - 24.90 during acclimatization; 20.61 - 25.80 during test period
- Humidity (%): 41.80 - 67.80 during acclimatization; 40.00 - 70.00 during test period
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Test solution preparation volume was determined based on the animal’s most recent body weight, and theoretical sample weight was calculated based on the designed dose. For each, the test sample was weighed, corn oil was added, mixed evenly to the mark (mixed with a homogeniser for 1 - 2 minutes, magnetically stirred for at least five minutes). All preparations were freshly prepared each time on the day of test chemical administration. Test chemical administration volume was 4 mL/kg.

VEHICLE
- Justification for use and choice of vehicle: Compared to water, the test sample can suspend better in oil.
- Concentration in vehicle: not reported
- Amount of vehicle: not reported
- Lot/batch no.: FN2018/12/19 and FN2019/01/25

Analytical verification of doses or concentrations:

no

Details on mating procedure:

- Impregnation procedure: cohoused
- M / F ratio per cage: 1 / 2
- Length of cohabitation: overnight
- Further matings after two unsuccessful attempts: yes (When there were no findings of impregnated rats, the above-described method of co-caging and mating continued, until the number of pregnant animals required for the test was reached.)
- Proof of pregnancy: vaginal plug or sperm in vaginal smear referred to as day 0 of pregnancy

Duration of treatment / exposure:

Day 5 - 19 after animal impregnation

Frequency of treatment:

daily, 7 days/week

Duration of test:

until Day 20 of pregnancy

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

15 mg/kg bw/day

Doses / concentrations 2

Dose / conc.:

60 mg/kg bw/day

Doses / concentrations 3

Dose / conc.:

240 mg/kg bw/day

No. of animals per sex per dose:

20

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on the results of a pre-test with concentrations 50, 100, 200, 300, 500, 700 and 1000 mg/kg bw/day, administered via oral gavage for 14 days
- Fasting period before blood sampling for (rat) dam thyroid hormones: not performed
- Time of day for (rat) dam blood sampling: not performed

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS / DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily
Cage side observations included changes in fur, eyes, mucous membranes, respiratory system, circulatory system, nervous system, as well as behavioural changes.

BODY WEIGHT: Yes
- Time schedule for examinations: weighed on days 0, 3, 5, 8, 11, 14, 17, and 20 of pregnancy

FOOD CONSUMPTION Yes
- Measured days 0 - 3, 3 - 5, 5 - 8, 8 - 11, 11 - 14, 14 - 17, and 17 - 20 of pregnancy
- Food consumption for each animal determined on days 0 - 3, 3 - 5, 5 - 8, 8 - 11, 11 - 14, 14 - 17, and 17 - 20 of pregnancy and mean diet consumption for the respective time intervals calculated as g food/test group
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No

WATER CONSUMPTION: No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- Organs examined: uterus and placenta

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Other: number of live foetuses, number of dead foetuses, number of resorped foetuses

Blood sampling:

Not performed

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: Yes: half per litter (visceral examinations) or all per litter (external examinations)
- Anogenital distance of all live rodent pups: no

Statistics:

SPSS 24.0 was used for statistical analysis of data.
Statistical analysis of mean body weight, weight gain, mean food intake, weight of uterus and foetuses, number of corpora lutea, number of implantations, weight of placenta, body length of foetal rat, tail length of foetal rat, and body weight of foetal rat were performed. First, the one-sample Kolmogorov-Smirnov test method was used to perform the normal distribution test on the data, then Levene’s test method was used to perform the homogeneity of variance test on the data. If there were findings of significant difference (P ≤ 0.05) for any statistical result from the one-sample Kolmogorov-Smirnov test and Levene’s test, then the independent sample Kruskal-Wallis test was performed. If there were findings that the results of the independent sample Kruskal-Wallis test were significantly differenent (P ≤ 0.05), then further pairwise comparison was performed. If there were no findings that the results of the independent sample Kruskal-Wallis test were significantly different (P > 0.05), then calculations ceased. If, in the statistical results of the one-sample Kolmogorov-Smirnov test and Levene’s test, there were no findings of significant difference (P > 0.05), then single-factor analysis of variance (ANOVA) was used. If the statistical results of single-factor analysis of variance (ANOVA) showed significant difference (P ≤ 0.05), the Dunnett test was used to perform testing on the control group and all dose groups. If the statistical results of the single-factor analysis of variance (ANOVA) showed no significant difference (P > 0.05), then calculations ceased. For dead foetus incidence rate, resorbed foetus incidence rate, male and female gender ratio, foetal rat appearance, visceral malformation incidence rate, and skeletal malformation incidence rate, the chi-square test was used to carry out statistical analysis.

Indices:

not performed

Historical control data:

not provided

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

After exposure to the test sample, four animals in the high dose group exhibited spontaneous declines in movement, and compared to the vehicle control group, there was a statistical significance (P ≤ 0.05); there were no anomalous symptoms in the low and medium dose groups. For details, see table 1.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

In the test period, body weight in all dose groups was compared to the vehicle control group, and there was no statistical significance (P > 0.05). In the high dose group, on days 5 - 8, weight gain was lower than in the vehicle control group, and it was statistically significant (P ≤ 0.001).

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

In the medium dose group, mean animal food intake quantity on days 8 - 11 was lower than in the vehicle control group, and it was statistically significant (P ≤ 0.05). However, there was no dose-response relationship and, in consideration of changes in body weight and weight gain, it can be concluded that these changes were not toxicologically significant. For details, see table 2.

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Endocrine findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

Weight of uterus and placenta were not affected compared to the vehicle control group.

Gross pathological findings:

not examined

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Maternal developmental toxicity

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Total litter losses by resorption:

no effects observed

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Changes in pregnancy duration:

not examined

Changes in number of pregnant:

no effects observed

Effect levels (maternal animals)

1

Key result

Dose descriptor:

NOAEL

Remarks:

maternal general toxicity

Effect level:

60 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: No effects observed at this dose level.

2

Key result

Dose descriptor:

LOAEL

Remarks:

maternal general toxicity

Effect level:

240 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

behaviour (functional findings)

body weight and weight gain

3

Key result

Dose descriptor:

NOAEL

Remarks:

maternal developmental toxicity

Effect level:

240 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: No effects observed up to the highest dose tested.

Maternal abnormalities

Key result

Abnormalities:

no effects observed

Results (fetuses)

Fetal body weight changes:

effects observed, treatment-related

Description (incidence and severity):

Body weight in foetal rats in the low and medium dose groups was compared to the vehicle control group and there was no statistical significance (P > 0.05). Foetal rat body weight in the high dose group was lower than in the vehicle control group, and there was statistical significance (P ≤ 0.001). For details, see table 3.

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

not specified

Anogenital distance of all rodent fetuses:

not examined

Changes in postnatal survival:

not examined

External malformations:

no effects observed

Skeletal malformations:

effects observed, treatment-related

Description (incidence and severity):

There were findings of one foetal rat with rib 14 accessory rib in the vehicle control group, five foetal rats in the low dose group, three foetal rats in the medium dose group, and 12 foetal rats in the high dose group. Incidence rates for rib 14 accessory rib in foetal rats in the low and medium dose groups were compared to the vehicle control group and they were not statistically significant (P > 0.05). The incidence rate for rib 14 accessory rib in the high dose group was higher than the vehicle control group and it was statistically significant (P ≤ 0.01). For details, see table 5.
There were findings of one foetal rat with 3rd sternebrae dumbbell-shaped ossification in the vehicle control group, five foetal rats in the low dose group, five foetal rats in the medium dose group, and 15 foetal rats in the high dose group. Incidence rates for 3rd sternebrae dumbbell-shaped ossification in the high dose group were higher than in the vehicle control group, and they were statistically significant (P ≤ 0.001). For details, see table 6.
There were findings of 22 foetal rats with 4th sternebrae dumbbell-shaped ossification in the vehicle control group, 43 foetal rats in the low dose group, 37 foetal rats in the medium dose group, and 69 foetal rats in the high dose group. Incidence rates for 4th sternebrae dumbbell-shaped ossification in foetal rats in the low and high dose groups compared to the vehicle control group were statistically significant (P ≤ 0.01, P ≤ 0.001). The medium dose group compared to the vehicle control group was not statistically significant (P > 0.05). For details, see table 7.
There were findings of zero foetal rats with 6th sternebrae deficiency in the vehicle control group, one foetal rat in the low dose group, one foetal rat in the medium dose group, and eight foetal rats in the high dose group. Incidence rates for 6th sternebrae deficiency in foetal rats in the high dose group were higher than in the vehicle control group and they were statistically significant (P ≤ 0.01). For details, see table 8.
There were findings of 26 foetal rats with 6th sternebrae incomplete ossification in the vehicle control group, 38 foetal rats in the low dose group, 42 foetal rats in the medium dose group, and 40 foetal rats in the high dose group. Incidence rates for 6th sternebrae incomplete ossification in foetal rats in all dose groups compared to the vehicle control group were statistically significant (P > 0.05). For details, see table 9.

In summary, foetal rat skeletons in the low dose group were compared to the vehicle control group and there was a statistically significant abnormal symptom, namely 4th sternebrae dumbbell-shaped ossification (P ≤ 0.01). Foetal rat skeletons in the medium dose group were compared to the vehicle control group and there were no statistically significant abnormal symptoms. Foetal rat skeletons in the high dose group were compared to the vehicle control group and there were statistically significant abnormal symptoms, namely 14th accessory rib (P ≤ 0.01), 3rd sternebrae dumbbell-shaped ossification (P ≤ 0.001), 4th sternebrae dumbbell-shaped ossification (P ≤ 0.001), and 6th sternebrae deficiency (P ≤ 0.01).
Of these, 4th sternebrae dumbbell-shaped ossification did not present a dose-response relationship in all dose groups, and no other skeletal abnormalities were exhibited in the low dose group, thus it did not possess toxicological significance. Based on the above results, the high dose had an impact on foetal rat skeletal development and increased the probability of skeletal abnormalities.

Visceral malformations:

effects observed, treatment-related

Description (incidence and severity):

There were findings of hydronephrosis in 17 foetal rats in the vehicle control group, 20 foetal rats in the low dose group, 24 foetal rats in the medium dose group, and 44 foetal rats in the high dose group. Incidence rates for hydronephrosis in foetal rats in the high dose group were higher than in the vehicle control group and there was statistical significance (P ≤ 0.001). For details, see table 4.

Other effects:

effects observed, treatment-related

Description (incidence and severity):

BODY LENGTH:
Foetal rat body length in the low dose group was compared to the vehicle control group and the difference was not statistically significant (P > 0.05). Foetal rat body length in the medium dose group was compared to the vehicle control group and it was statistically significant (P ≤ 0.001). Foetal rat body length in the high dose group was lower than in the vehicle control group, and it was statistically significant (P ≤ 0.001). As body length effects did not present a dose-response relationship and, in consideration of the fact that foetal rat body weight in the medium dose group did not present statistical significance, it was concluded that the effects observed in the medium-dose group were not toxicologically significant. For details, see table 3.

TAIL LENGTH:
Tail length in the low and medium dose groups was compared to the vehicle control group and there was no statistical significance (P > 0.05); foetal rat tail length in the high dose group was lower than in the vehicle control group, and there was statistical significance (P ≤ 0.001). For details, see table 3.

Effect levels (fetuses)

1

Key result

Dose descriptor:

NOAEL

Remarks:

developmental toxicity

Effect level:

60 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No effects observed at this dose level.

2

Key result

Dose descriptor:

LOAEL

Remarks:

developmental toxicity

Effect level:

240 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

visceral malformations

Fetal abnormalities

1

Key result

Abnormalities:

effects observed, treatment-related

Localisation:

external: tail

Description (incidence and severity):

Total tail length in the high dose group was statistically singnificantly lower than in the vehicle control group. In addition, foetal rat body length and foetel body weight in the high dose group were statistical singnificantly lower than in the vehicle control group.

2

Key result

Abnormalities:

effects observed, treatment-related

Localisation:

visceral/soft tissue: urinary

Description (incidence and severity):

Incidence rates for hydronephrosis in foetal rats in the high dose group were higher than in the vehicle control group and there was statistical significance (P ≤ 0.001).

3

Key result

Abnormalities:

effects observed, treatment-related

Localisation:

skeletal: rib

Description (incidence and severity):

The incidence rate for rib 14 accessory rib in the high dose group was higher than the vehicle control group and it was statistically significant (P ≤ 0.01).

4

Key result

Abnormalities:

effects observed, treatment-related

Localisation:

skeletal: sternum

Description (incidence and severity):

There were findings of one foetal rat with 3rd sternebrae dumbbell-shaped ossification in the vehicle control group, five foetal rats in the low dose group, five foetal rats in the medium dose group, and 15 foetal rats in the high dose group. Incidence rates for 3rd sternebrae dumbbell-shaped ossification in the high dose group were higher than in the vehicle control group, and they were statistically significant (P ≤ 0.001).
Statistically abnormal symptoms in the foetal rat skeleton of the high dose group were: 14th accessory rib (P ≤ 0.01), 3rd sternebrae dumbbell-shaped ossification (P ≤ 0.001), and 6th sternebrae deficiency (P ≤ 0.01).
There were findings of zero foetal rats with 6th sternebrae deficiency in the vehicle control group, one foetal rat in the low dose group, one foetal rat in the medium dose group, and eight foetal rats in the high dose group. Incidence rates for 6th sternebrae deficiency in foetal rats in the high dose group were higher than in the vehicle control group and they were statistically significant (P ≤ 0.01).
There were findings of 26 foetal rats with 6th sternebrae incomplete ossification in the vehicle control group, 38 foetal rats in the low dose group, 42 foetal rats in the medium dose group, and 40 foetal rats in the high dose group. Incidence rates for 6th sternebrae incomplete ossification in foetal rats in all dose groups compared to the vehicle control group were statistically significant (P > 0.05).

Overall developmental toxicity

Key result

Developmental effects observed:

yes

Lowest effective dose / conc.:

240 mg/kg bw/day

Treatment related:

yes

Relation to maternal toxicity:

developmental effects occurring together with maternal toxicity effects, but not as a secondary non-specific consequence of maternal toxicity effects

Dose response relationship:

yes

Relevant for humans:

presumably yes

Any other information on results incl. tables

Table 1: Maternal effects - Clinical Signs

Observation	Vehicle control group	Dose groups
	0 mg/kg	15 mg/kg	60 mg/kg	240 mg/kg
Appearance, fur	0/20	0/20	0/20	0/20
Posture	0/20	0/20	0/20	0/20
Urine, faeces	0/20	0/20	0/20	0/20
Noise reflex	0/20	0/20	0/20	0/20
Reaction sensitivity	0/20	0/20	0/20	0/20
Eyes, nose, mouth	0/20	0/20	0/20	0/20
Skin	0/20	0/20	0/20	0/20
Chest and abdomen	0/20	0/20	0/20	0/20
Lower abdominal area	0/20	0/20	0/20	0/20
Muscle tension	0/20	0/20	0/20	0/20
Respiration	0/20	0/20	0/20	0/20
Movement	0/20	0/20	0/20	4*/20
Neurology	0/20	0/20	0/20	0/20
Head	0/20	0/20	0/20	0/20

Notes: Movement abnormality was spontaneous reduction in movement; compared to the vehicle control group: *P ≤ 0.05.

 

Table 2: Maternal effects - Body weight gain changes

Date	Vehicle control group	Dose group
	0 mg/kg	15 mg/kg	60 mg/kg	240 mg/kg
d0-d3	16.50 ± 8.88	19.20 ± 6.53	20.59 ± 9.14	15.65 ± 8.96
d3-d5	10.43 ± 7.46	10.57 ± 7.36	8.83 ± 6.51	10.93 ± 5.65
d5-d8	14.54 ± 8.88	8.48 ± 5.86	11.43 ± 27.89	-4.82 ± 12.63***
d8-d11	11.84 ± 12.45	16.47 ± 5.24	11.71 ± 23.90	20.20 ± 9.66
d11-d14	15.80 ± 12.27	21.14 ± 12.28	17.84 ± 18.14	16.21 ± 7.20
d14-d17	33.57 ± 6.19	41.38 ± 9.70	35.64 ± 10.45	29.42 ± 8.56
d17-d20	54.71 ± 9.81	50.05 ± 13.27	50.28 ± 7.62	48.13 ± 7.70

Compared to the vehicle control group: ***P ≤ 0.001; unit: g

 

 

Table 3: Foetal effects - Body length, tail length and body weight

Group	Dose (mg/kg)	Mean body length (cm)	Mean tail length (cm)	Mean body weight (g)
Vehicle control group	0	3.841 ± 0.142	1.395 ± 0.055	4.005 ± 0.368
Low dose group	15	3.840 ± 0.138	1.406 ± 0.053	4.093 ± 0.358
Medium dose group	60	3.786 ± 0.148***	1.396 ± 0.064	3.957 ± 0.370
High dose group	240	3.742 ± 0.164***	1.371 ± 0.058***	3.768 ± 0.459***

Compared to the vehicle control group: ***P ≤ 0.001

 

 

Table 4: Foetal effects - Visceral examination (Hydronephrosis)

Group	Dose (mg/kg)	Incidence number (n)	Number of foetal rats examined (n)	Incidence rate (%)
Vehicle control group	0	17	137	12.41%
Low dose group	15	20	150	13.33%
Medium dose group	60	24	148	16.22%
High dose group	240	44***	144	29.17%

Compared to the vehicle control group: ***P ≤ 0.001

 

 

Table 5: Foetal effects - Skeletal examination (Rib 14 Accessory Rib)

Group	Dose (mg/kg)	Incidence number (n)	Number of foetal rats examined (n)	Incidence rate (%)
Vehicle control group	0	1	129	0.78%
Low dose group	15	5	139	3.60%
Medium dose group	60	3	142	2.11%
High dose group	240	12**	136	8.82%

Compared to the vehicle control group: **P ≤ 0.01.

 

Table 6: Foetal effects - Skeletal examination (3^rd Sternebrae Dumbbell-Shaped Ossification)

Group	Dose (mg/kg)	Incidence number (n)	Number of foetal rats examined (n)	Incidence rate (%)
Vehicle control group	0	1	129	1.55%
Low dose group	15	5	139	3.60%
Medium dose group	60	5	142	3.52%
High dose group	240	15***	136	11.03%

Compared to the vehicle control group: ***P ≤ 0.001

 

 

Table 7: Foetal effects - Skeletal examination (4^th Sternebrae Dumbbell-Shaped Ossification)

Group	Dose (mg/kg)	Incidence number (n)	Number of foetal rats examined (n)	Incidence rate (%)
Vehicle control group	0	22	129	16.28%
Low dose group	15	43**	139	30.94%
Medium dose group	60	37	142	26.06%
High dose group	240	69***	136	50.74%

Compared to the vehicle control group: **P ≤ 0.01; ***P ≤ 0.001

 

 

Table 8: Foetal effects - Skeletal examination (6^th Sternebrae Deficiency)

Group	Dose (mg/kg)	Incidence number (n)	Number of foetal rats examined (n)	Incidence rate (%)
Vehicle control group	0	0	129	0.00%
Low dose group	15	1	139	0.72%
Medium dose group	60	1	142	0.70%
High dose group	240	8**	136	5.88%

Compared to the vehicle control group: **P ≤ 0.01

 

Table 9: Foetal effects - Skeletal examination (6^th Sternebrae Incomplete Ossification)

Group	Dose (mg/kg)	Incidence number (n)	Number of foetal rats examined (n)	Incidence rate (%)
Vehicle control group	0	26	129	20.16%
Low dose group	15	38	139	27.34%
Medium dose group	60	42	142	29.58%
High dose group	240	40	136	29.41%

 

 

 

 

Applicant's summary and conclusion

Conclusions:

Under the conditions of this test, based on the described effects, the minimum effects dose (LOAEL) of 2-nitro-4-(trifluoromethyl)benzonitrile in the prenatal developmental toxicity test in rats for foetal development was 240 mg/kg bw/day, and the maximum no effects dose (NOAEL) was 60 mg/kg bw/day. For maternal toxicity, the NOAEL for general toxicity was 60 mg/kg bw/day and the respective LOAEL was at 240 mg/kg bw day. As no maternal developmental toxicity was observed at any of the doses tested, the NOAEL for maternal developmental toxicity was 240 mg/kg bw/day.
Based on the findings of hydronephrosis in the offspring, a classification of Repr. 2 is warranted.