α,α,α-trifluoro-4-nitro-m-cresol

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

In a 3-generation study similar to OECD guideline 416 in rats (RED, 1999), no effect of the test substance on fertility was observed.

Link to relevant study records

Reference

Endpoint:

three-generation reproductive toxicity

Type of information:

experimental study

Adequacy of study:

other information

Study period:

1971 to 1973

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)

Version / remarks:

2001-01-22

GLP compliance:

not specified

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source of test material:
Samples of TFM used for this study carried the following label information:
1-21-5479 C31 51315/1
JFK AIRPORT ATTN AMERICAN HOECHST CORP SOMMERVILLE N. J. MR. KUFAHL CHEM. DEPT.
MADE IN WEST GERMANY

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Sprague-Dawley, Madison, Wisconsin, USA
- Females nulliparous and non-pregnant: yes
- Age at study initiation: (P0) ~3 - 4 weeks
- Housing: individually, in metal screen bottom cages, 7" x 7" x 9 3/4"
- Diet: ad libitum, Purina Laboratory Chow from specially capped clear glass jars that limit spillage and contamination of feed and provide visibility of amount and condition of feed.
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 ± 2
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: feed

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: The appropriate amount of TFM (85.6 %) was brought up to 1 % by weight of the diet with corn oil. The TFM and corn oil were thoroughly mixed, then totally admixed with the basal diet. The negative control diet consisted of the basal diet with a 1 % by weight addition of corn oil.

DIET PREPARATION
- Mixing appropriate amounts with: Purina Laboratory Chow (pellets)

VEHICLE
- Justification for use and choice of vehicle: In addition to facilitating good distribution of the test materials, the addition of the corn oil eliminated dusting, thus preventing personnel contamination and cross contamination of test animals from different diet groups.

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: one week
- Proof of pregnancy: vaginal plug referred to as day 1 of pregnancy.
- After seven days of unsuccessful pairing replacement of first male by another male with proven fertility.
- After successful mating each pregnant female was caged: Approximately five days prior to parturition, females were placed in plastic shoe box cages equipped with a stainless steel topf food jar, and water bottle. Bedding (AB-SORB-DRI) was changed three times weekly or more often if needed through weaning. After being placed in shoe boxes, females were allowed to deliver and care for their own young with a minimum of disturbance.

Duration of treatment / exposure:

After approximately 13 weeks on test diets, (18 weeks for the F0 generation), females were mated one to one with males from the same diet group.

Frequency of treatment:

continously

Details on study schedule:

The following description pertains to animals selected for reproduction studies from the F0, F1a, and F2b generations.
After approximately 13 weeks on test diets, (18 weeks for the Fo generation), females were mated one to one with males from the same diet group.
One week after weaning of the F2a or F3a litters, the parent generation was mated again in the described manner to produce a second litter.

Dose / conc.:

300 ppm

Remarks:

Group 8, conversion with generic animal data according to "Reproductively Active Chemicals" (factor for adult rats: 0.08)
300 ppm = 24 mg/kg bw/day

Dose / conc.:

1 250 ppm

Remarks:

Group 9, conversion with generic animal data according to "Reproductively Active Chemicals" (factor for adult rats: 0.08)
1250 ppm = 100 mg/kg bw/day

Dose / conc.:

5 000 ppm

Remarks:

Group 10, conversion with generic animal data according to "Reproductively Active Chemicals" (factor for adult rats: 0.08)
5000 ppm = 400 mg/kg bw/day

No. of animals per sex per dose:

40 (F0), 20 (F1, F2)

Control animals:

yes, concurrent vehicle

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes
- If yes, maximum of 40 pups/litter (20/sex/litter as nearly as possible); excess pups were killed and discarded.

PARAMETERS EXAMINED
The following parameters were examined in [F1 / F2 / F3] offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain

GROSS EXAMINATION OF DEAD PUPS:
Yes

Reproductive indices:

mating index, fertility index, gestation index

Offspring viability indices:

viabilty index, survival index, lactation index

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

In general, the data and calculated indexe appear normal for test and control groups. The fertility index, though normal, was slightly lower, for Group 9 (mid level TFM). Gestation index was excellent for all groups. Average numbers of pups born per litter were normal and no differences existed among the groups.

Key result

Dose descriptor:

NOAEL

Effect level:

400 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive performance

Key result

Critical effects observed:

no

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

A slightly lower fertility index (75 %) was seen in Group 9 (mid level TFM) when compared to the negative control group (90 %). Average numbers of pups born per litter were within normal limits. Viability index was good for all groups (89 - 96 %). Survival on day 4 is good for all groups and average pup weights were normal (8.6 g - 9.1 g). At day 21 (weaning), survival was good in all groups but average weaning weights were slightly smaller in Group 10 (45 g) when compared with weights in the negative control group, Group 7 (48 g).
Data from the second litter of the F1a generation (F2b litter) showed no changes in Fertility index and Mating index in the treament groups cmpared to the control group.
The number of newborn pups was not affected by the treatment.

Key result

Dose descriptor:

NOAEL

Effect level:

400 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

reproductive performance

Key result

Critical effects observed:

no

Clinical signs:

no effects observed

Mortality / viability:

mortality observed, non-treatment-related

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Group 10 (high level TFM) revealed reduced weaning weights in all litters (3 - 6 g) when compared to group 7 (negative control).

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Other effects:

not examined

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

not examined

A lower viability index was seen in Group 9 when compared to the other test and control groups. The primary cause for this lower viability index was that two litters accounted for a total of 21 dead pups, and not that all litters had a greater number of stillbirths. Survival, and lactation indexes were excellent for all groups. At 4 days average pup weights were normal, though smaller weights were seen in the high level TFM group (Group 10). At 21 days (weaning) depressed weights were seen in the high level TFM group (Group 10). Average weaning weight in Group 10 were 43 g and Group 12 46 g compared to 48 g - 49 g for other test and control groups. No other differences were seen among the groups regarding the reproduction data from F1a litters.

Key result

Dose descriptor:

NOAEL

Generation:

F1a

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Key result

Critical effects observed:

no

Clinical signs:

no effects observed

Mortality / viability:

mortality observed, non-treatment-related

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Group 10 (high level TFM) revealed reduced weaning weights in all litters (3 - 6 g) when compared to Group 7 (negative control).

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Ophthalmological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

no effects observed

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Other effects:

not examined

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

not examined

Viability was good for all groups (93 - 98 %). Only Group 9 showed day 4 pup weights below 10 g (9.1 g vs. 10.5 g in Group 7). At 21 days survival was good in all groups. Group 10 had average pup weights of 46 g and Group 8 had a weight of 48 g compared to 52 g seen in Group 7.

Key result

Dose descriptor:

NOAEL

Generation:

F2b

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Key result

Critical effects observed:

no

Key result

Reproductive effects observed:

no

Additionally, the effects on a third generation were observed:

F3a: First litter data for the F2b generation revealed generally normal values for most groups. Group 10 showed a slightly lower number of pregnancies, Fertility index - 74 %, when compared to Group 7 (94 %). Mating indexes are essentially equal for all groups. Smaller average numbers of pups were born in Groups 10 and 12 (10.5 and 9.7) when compared to Group 7 (12.0). Viability was good (89 - 97 %) for all groups. Survival was good for all groups at day 4. Average pup weights at day 4 were normal for all groups. Survival was good in all groups at weaning (day 21). Weaning weights were slightly smaller in Group 10 than Group 7 (45 g vs. 48 g).

F3b: Fertility indexes were down or unchanged in all groups when compared with indexes of F3a litters. Mating indexes were, in general, up for all groups. Though within a normal range, smaller average numbers of pups were born in Groups 10 compared with Group 7. Groups 10 averaged 10.9 pups per litter compared with 13.0 pups in Group 7. Survival was good in all groups through weaning. Pup weights at day 4 were normal and revealed no differences among the groups. At 21 days a smaller average pup weight was seen in Group 10 (47 g) when compared with Group 7 (52 g).

Summary:

Overall reproductive performance in rats was generally good for most groups in all five litters (representing 3 generations) examined. Though some slight variations from litter to litter were seen, all average data and reproductive indexes were essentially normal and no significant reproductive differences were observed between the low level TFM or mid level TFM groups and the negative control group. A slightly lower Fertility index was observed in one or two groups from various litters. General overall fertility showed no abnormal variations between control and test groups, however. Gestation indexes were good throughout the study; essentially all positive pregnancies resulted in live births. Viability (Viability index) and survival through weaning (Survival index, Lactation index) were good for all groups through 3 generations. The average numbers of pups born per litter were, in most cases, within the normal range for this laboratory of approximately 9 - 12. Approximately half of the individual litters born in any given reproduction showed reduced number of pups born when compared to a normal range. Group 10 (high level TFM) revealed slightly reduced average numbers of pups born in both F3 litters when compared to the negative control. Average pup weights at day 4 showed slight variations among the groups, but all average weights were normal and no trend exists through 3 generations. At 21 days, weaning weights were normal and no consistent differences existed between the negative control group and the low and mid TFM groups. Group 10 (high level TFM) revealed reduced weaning weights in all litters (3 - 6 g) when compared to Group 7 (negative control).

Conclusions:

In this 3-generation study similar to OECD guideline 416 in rats, no effect of the test substance on fertility was observed.

Executive summary:

In this study, the test substance was administered to 40 sex/dose (F0), or 20 sex/dose (F1, F2) Sprague-Dawley rats in diet at dose levels of 0, 300.0, 1250.0, and 5000.0 ppm (0, 24, 100, or 400 mg/kg bw/day). No changes in the reproductive indices of the treatment groups compared to the control group were observed in any generation. The only treatment-related effect observed was a reduction of weaning weights in the high dose group in the F1 and F2 generation.

Based on these observation, following NOAEL were determined:

P0: 5000 ppm (400 mg/kg bw/day) based on reproductive performance

P1:5000 ppm (400 mg/kg bw/day) based on reproductive performance

F1: 1250 ppm (100 mg/kg bw/day) based on body weight and weight gain

F2b:1250 ppm (100 mg/kg bw/day) based on body weight and weight gain

However, it can be assumed, that the observed weight difference between untreated control animals and treated animals (400 mg/kg bw/day) at weaning, is a transient effect. Comparing the weight gain of the femal P0, P1 and P2 animals of the corresponding treatment groups, no differences in bodyweight can be observed. Therefore, the observed weight difference at weanlings is not an adverse effect.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

400 mg/kg bw/day

Study duration:

chronic

Species:

rat

Quality of whole database:

Klimisch code 2

Additional information

In a 3-generation reproduction study similar to OECD guideline 416 (RED, 1999; WARF Institute, 1973), the test substance was administered to 40 sex/dose (F0), or 20 sex/dose (F1, F2) Sprague-Dawley rats in diet at dose levels of 0, 300.0, 1250.0, and 5000.0 ppm (0, 24.0, 100.0, or 400.0 mg/kg bw/day). No changes in the reproductive indices of the treatment groups compared to the control group were observed in any generation.

Based on these observation, following NOAEL were determined:

P0: 5000 ppm (400 mg/kg bw/day) based on reproductive performance

P1: 5000 ppm (400 mg/kg bw/day) based on reproductive performance

F1: 1250 ppm (100 mg/kg bw/day) based on body weight and weight gain

F2b: 1250 ppm (100 mg/kg bw/day) based on body weight and weight gain

However, it can be assumed, that the observed weight difference between untreated control animals and treated animals (400 mg/kg bw/day) at weaning, is a transient effect. Comparing the weight of the adult female P0, P1 and P2 animals of the corresponding treatment groups, no differences in bodyweight can be observed. Therefore, the observed weight difference at weaning is not an adverse effect.

Effects on developmental toxicity

Description of key information

In a developmental toxicity study similar to OECD guideline 414 (Hazleton Laboratories, 1983), the test substance showed no developmental toxicity.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1982-10-13 to 1983-03-07

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source of test material: Hoechst, Lamprecide FCL #1409, HRI No* 975297

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature, ambient conditions

Species:

rat

Strain:

Crj: CD(SD)

Remarks:

COBS

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Kingston, New York, USA facility of Charles River Breeding Laboratories, Wilmington, Massachusetts, USA
- Age at study initiation: 7 - 9 weeks
- Housing: stainless steel wire mesh cages (67 in²)
- Diet: ad libitum, Purina Certified Rodent Chow (#5002)
- Water: ad libitum, automatic watering system
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 50 ± 20
- Air changes (per hr): 10 - 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

VEHICLE
- Amount of vehicle: 5 mL/kg bw
- Lot/batch no.: 101F-0141, Sigma Chemical Company, St. Louis, Missouri, USA

Details on mating procedure:

- Impregnation procedure: cohoused
- M/F ratio per cage: 1/1
- Proof of pregnancy: vaginal plug and sperm in vaginal smear referred to as day 0 of pregnancy.

Duration of treatment / exposure:

Day 6 to day 15 of gestation

Frequency of treatment:

daily

Duration of test:

20 days

Dose / conc.:

25 other: mg/5 mL/kg bw

Dose / conc.:

125 other: mg/5 mL/kg bw

Dose / conc.:

250 other: mg/5 mL/kg bw

No. of animals per sex per dose:

25 ♀/per dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on the results of a range finding study.

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations were included.

BODY WEIGHT: Yes
- Time schedule for examinations: Day 0, 6, 9, 12, 15, 18, and 20

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: ovaries, uterus

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
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter

Statistics:

The litter or dam was considered the experimental unit for evaluation, although data on individual fetuses with abnormalities also were considered. Differences were considered significant at p < 0.05.
Dam body weight on Day 0 and the corrected and uncorrected change in weight between Days 0 and 20 were analyzed by analysis of variance, and, when significant, treatment means were compared with control means using Dunnett's multiple comparison test. Dam body weights on Days 6 and 20, gravid uterine weight, and corrected weight on Day 20 were analyzed by covariate analysis using Day 0 body weight as the covariate. Dunnett's test was performed on means adjusted for the covariate where covariate analyses indicated significant differences.
Number of corpora lutea; number of implants; implantation efficiency; number -and percent of live, resorbed, and dead fetuses; and sex ratio were analyzed using the Kruskal-Wallis test. Where significant differences were indicated, Dunn's test was performed. Mean fetus weight was analyzed by covariate analysis using the number of live fetuses as the covariate. Dunnett's test was performed on means adjusted for the covariate where covariate analysis indicated significant differences.
The number of litters with fetal gross, visceral, and skeletal abnormalities was analyzed by contingency table techniques (Chi²). Where overall significant treatment differences were indicated, treated groups were compared with the control group using the Chi² statistic for the appropriate 2x2 tables, correcting the significance levels for the number of comparisons being made.
The percent of litters with fetal gross, visceral, and skeletal abnormalities was analyzed using the Kruskal-Wallis test. Where significant differences were indicated, Dunn's test was performed.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Salivation following treatment (observed in all treatment groups). Reddish-brown vaginal discharge (associated with a placental sign) in one animal in the 25 mg/kg group. Flaccid body tone for one animal; pawing and rubbing of the cage bottom following treatment for one animal in the 125 mg/kg group. Yellow-stained muzzle and forepaws for two animals and pronation and lethargy following treatment for one animal in the 250 mg/kg group. In addition, one animal had a rough coat.

Mortality:

mortality observed, treatment-related

Description (incidence):

Two animals in the 250 mg/kg group died on Day 6 (the first day of treatment) and Day 12 of gestation, respectively.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

There were no statistically significant differences in mean body weights and weight changes between Days 0 and 20 of gestation

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Renal pelvic cavitation was noted in all groups, and indentations were observed in the cortex of the kidney for one animal each in the 25 mg/kg group and the 250 mg/kg group. In addition, one kidney in one animal was pitted, and a mottled kidney was reported for one animal in the 125 mg/kg group. Other necropsy observations included fused placentae for one animal and a darkened and slightly enlarged liver for one animal in the 125 mg/kg group.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

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:

no effects observed

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed

Changes in number of pregnant:

no effects observed

Key result

Dose descriptor:

NOAEL

Effect level:

125 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

mortality

Dose descriptor:

LOAEL

Effect level:

250 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

mortality

Key result

Abnormalities:

no effects observed

Fetal body weight changes:

no effects observed

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): no effects observed

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

no effects observed

External malformations:

no effects observed

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

Unossified hyoids, unossified sternebrae, rudimentary ribs, and anomalies of the centra were found in control and treated groups in a nontreatmeht related pattern.

Visceral malformations:

effects observed, non-treatment-related

Description (incidence and severity):

Unilateral renal pelvic cavitation (anomaly) was found in control and treated groups with the following incidence: one fetus from one litter in the control group; two fetuses from two litters each in the 25 mg/kg group and 125 mg/kg group; and five fetuses from four litters in the 250 mg/kg group. In addition, one fetus from one animal in the 250 mg/kg group had bilateral renal pelvic cavitation. Although these data are not statistically significant, they may indicate a fetotoxic response or be an expression of delayed development due to compound-related fetal stress. Dilated ureters (anomaly), associated with the renal pelvic cavitation, were noted in one fetus in the control group and two fetuses in the 250 mg/kg group. A dilated ureter not associated with renal pelvic cavitation was noted in one fetus from one animal in the 125 mg/kg group. Observations for the high-dose group only included one case each of a small (anomaly) and an absent testis (malformation).

Key result

Dose descriptor:

NOAEL

Effect level:

250 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

visceral malformations

Key result

Abnormalities:

no effects observed

Key result

Developmental effects observed:

no

Table 1: Maternal Toxicity	TMF mg/kg bw
	0	25	125	250
Dams on study	25	25	25	25
Dams examined on Day 20	25	25	25	23
Dams with implantations	24	25	23	23
Percent with implantations	96	100	92	100
Corpora lutea, Mean	15	15	16	16
S.D.	1.7	1.7	2.3	1-8
Implantations, Mean	14	13	14	14
S.D.	3.1	4.1	3.3	4.1
Implantation efficiency, Mean	93.3	86.2	86.3	89.8
S.D.	18.21	25.54	19.69	23.54
Litters with live fetuses	24	25	23	23
Total live fetuses	332	317	297	299
Live fetuses,Mean	14	13	13	13
S.D.	3.1	3.9	3.4	4.7
Percent live fetuses, Mean	100.0	100.0	100.0	100.0
S.D.	0.00	0.00	0.00	0.00
Fetal weight (g), Mean	3.5	3.6	3.5	3.5
S.D.	0.18	0.29	0.26	0.22
Sex ratio [(M/M+F) X 100], Mean	51.9	54.7	48.7	46.7
S.D.	16.35	15.06	lb.86	18.88
Litters with resorbed fetuses	9	12	11	11
Total resorbed fetuses	14	17	16	26
Resorbed fetuses, Mean	1	1	1	1
S.D.	0.9	0.9	0.9	2.5
Percent resorbed fetuses, Mean	3.8	4.7	5.5	8.6
S.D.	5.80	5.93	7.09	16.73

 

Table 2: Fetal abnormalities	TMF mg/kg bw
	0	25	125	250
Soft tissue:
Renal pelvic cavitation	1 (1)	2 (2)	2 (2)	6 (5)
Dilated ureters	1 (1)	1 (1)	0	2 (2)
Small testis	0	0	0	1 (1)
Absent testis	0	0		1 (1)
Skeletal
Malformed scapulae	1 (1)	0	0	0
Malformed/bent forelimbs	1 (1)	0	0	0
Bent ribs	1 (1)	0	0	0

Number in brackets represent the number of litters affected

Conclusions:

In this developmental toxicity study similar to OECD guideline 414 (Hazleton Laboratories, 1983), the test substance showed no developmental toxicity.

Executive summary:

In a developmental toxicity study similar to OECD guideline 414 (Hazleton Laboratories, 1983), pregnant COBS® CD® (SD) Br rats (25/group) received the test substance by oral gavage at doses of 0 (corn oil vehicle), 25, 125, or 250 mg/kg bw/day on gestation days (GD) 6 - 15, inclusive. It was not specified whether doses were adjusted for percent active ingredient. On GD 20, all dams were sacrificed and all fetuses were examined for external malformations/variations. Approximately one-half of each litter was placed in Bouin’s fixative for subsequent visceral examination and the remainder stained for skeletal examination. All animals in the control, low-, and mid-dose groups survived until scheduled sacrifice. Two high-dose dams died during the treatment interval, one on GD 6 and the other on GD 12 and the study author stated that the deaths were treatment related. The only other clinical sign of toxicity was salivation which was observed in 0/25, 0/25, 2/25, and 22/25 (p < 0.01) animals in the 0, 25, 125, and 250 mg/kg bw/day groups, respectively. There were no significant differences in maternal body weights between the treated and control groups at any time during gestation. Food consumption was not measured. Therefore, the maternal toxicity LOAEL is 250 mg/kg bw/day based on mortality. The corresponding maternal toxicity NOAEL was 125 mg/kg bw/day. No treatment-related effects were observed for gravid uterine weights, number of fetuses/litter, pre- and postimplantation loss, numbers of corpora lutea/dam, number of implantations/dam, resorptions/dam, fetal body weights, or fetal sex ratios. No statistically significant differences in the incidence rates of any external, visceral, or skeletal malformations/variations were observed in the treated litters as compared to the controls.

Therefore, no treatment related teratogenic effects were abserved. The NOAEL for developmental toxicity is 250 mg/kg/day.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

250 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Klimisch code 2

Additional information

In a developmental toxicity study similar to OECD guideline 414 (Hazleton Laboratories, 1983), pregnant COBS® CD® (SD) Br rats (25/group) received the test substance by oral gavage at doses of 0 (corn oil vehicle), 25, 125, or 250 mg/kg bw/day on gestation days (GD) 6 - 15, inclusive. It was not specified whether doses were adjusted for percent active ingredient. On GD 20, all dams were sacrificed and all fetuses were examined for external malformations/variations. Approximately one-half of each litter was placed in Bouin’s fixative for subsequent visceral examination and the remainder stained for skeletal examination. All animals in the control, low-, and mid-dose groups survived until scheduled sacrifice. Two high-dose dams died during the treatment interval, one on GD 6 and the other on GD 12 and the study author stated that the deaths were treatment related. The only other clinical sign of toxicity was salivation which was observed in 0/25, 0/25, 2/25, and 22/25 (p < 0.01) animals in the 0, 25, 125, and 250 mg/kg bw/day groups, respectively. There were no significant differences in maternal body weights between the treated and control groups at any time during gestation. Food consumption was not measured. Therefore, the maternal toxicity LOAEL is 250 mg/kg bw/day based on mortality. The corresponding maternal toxicity NOAEL was 125 mg/kg bw/day. No treatment-related effects were observed for gravid uterine weights, number of fetuses/litter, pre- and postimplantation loss, numbers of corpora lutea/dam, number of implantations/dam, resorptions/dam, fetal body weights, or fetal sex ratios. No statistically significant differences in the incidence rates of any external, visceral, or skeletal malformations/variations were observed in the treated litters as compared to the controls.

Therefore, no treatment related teratogenic effects were observed. The NOAEL for developmental toxicity is 250 mg/kg/day.

Justification for classification or non-classification

The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008.

A NOAEL of 400 mg/kg bw/day (highest dose) was determined in rats for parental fertility and a NOAEL of 250 mg/kg bw/day (highest dose) was determined in rats for teratogenicity. As a result the test substance is considered not to be classified for toxicity for reproduction under Regulation (EC) No 1272/2008, as amended for the tenth time in Regulation (EC) No 2017/776.