Pyrazole

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Effects on developmental toxicity

Description of key information

Rat Developmental Gavage: Not a unique developmental toxin (NOAEL maternal toxicity = 1 mg/kg/day; NOAEL fetotoxicity = 5 mg/kg/day; NOAEL teratogenicity = 15 mg/kg/day). Reliability = 2

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Acceptable, well documented publication/ study report which meets basic scientific principles.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Pregnant female rats were exposed to the test substance on gestation days 6-15 to examine the maternal and developmental toxicity potential of the substance.

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Remarks:

Crl:CD®BR

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Inc., Portage, Michigan
- Weight at study initiation: mean of 225-278 g
- Fasting period before study: not reported
- Housing: Until pairing, all animals were individually housed in clean, wire-mesh cages suspended above cage-board. The animals were paired for mating in the home cage of the male. Following positive identification of mating, the females were returned to an individual suspended wire-mesh cage; nesting material was not required as the females were sacrificed prior to expected parturition
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: minimum of 10 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3°C
- Humidity (%): 40+-66%
- Air changes (per hr): approximately 10-15
- Photoperiod (hrs dark / hrs light): 12 hrs dark/ 12 hrs light

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:A sufficient amount of test material was weighed for all groups, transferred to a mortar and ground into a fine powder. The appropriate amount of the ground material was weighed for each group. The vehicle was added to the test material in small increments and ground with a pestle until a slurry was obtained. The mixture was transferred to a graduated cylinder via a series of vehicle rinses. A sufficient amount of vehicle was added to attain a volume of 200 mL. The cylinder was inverted several times to ensure adequate mixing and the contents were transferred to a labelled storage container. The cylinder was rinsed with an additional 60 mL of vehicle which was then added to the storage container. The solutions were visually inspected for homogeneity prior to dispensing on the first day of test material administration. Solutions for aldose groups were prepared once and were stored refrigerated. The solutions were stirred each day prior to dispensing and during the dosing procedures.

Analytical verification of doses or concentrations:

no

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1:1
- Length of cohabitation: until mating occurred
- Proof of pregnancy: copulatory plug in the vagina or the presence of sperm in a vaginal smear

Duration of treatment / exposure:

gestation days 6-15

Frequency of treatment:

daily

Duration of test:

20 days

Dose / conc.:

1 mg/kg bw/day

Dose / conc.:

5 mg/kg bw/day

Dose / conc.:

10 mg/kg bw/day

Dose / conc.:

15 mg/kg bw/day

Dose / conc.:

20 mg/kg bw/day

No. of animals per sex per dose:

8

Control animals:

yes

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Twice daily
- Cage side observations checked: moribundity and mortality

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Days 0 through 20 of gestion (prior to dosing during the treatment period). In addition, animals were observed for signs of toxicity approximately 1 hour following dosing

BODY WEIGHT: Yes
- Time schedule for examinations: Individually on gestation days 0, 6, 9, 12, 16, 18, and 20. A group mean body weight was calculated. Mean body weight changes were calculated for each corresponding interval and also for days 6-16 and 0-20.

FOOD CONSUMPTION: No

WATER CONSUMPTION: No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- Organs examined: Liver, kidneys, spleen, and thyroid were excised, trimmed and weighed

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: Uteri with no macroscopic evidence of nidation were excised, opened and subsequently placed in 10% ammonium sulfide solution for detection of early implanation loss.

Fetal examinations:

- External examinations: Yes: [all per litter]
- Soft tissue examinations: No
- Skeletal examinations: No
- Head examinations: No

Statistics:

All analyse were conducted using two-tailed tests for a minimum significance level of 5% comparing each treated group to the control group. The numbers of early and late resorptions, dead foetuses and post implantation losses were compared by the Mann-Whitney U-test. The numbers of litters with malformations and variations were compared by Fisher’s Exact test. Mean numbers of corpora lutea, total implantations, viable foetuses, mean foetal and maternal body weights at each interval, maternal body weight gain and organ weights were analysed by a one-way analysis of variance and Dunnett’s test. The foetal sex ratios were compared by the Chi Square test with Yates correction factor.

Clinical signs:

no effects observed

Description (incidence and severity):

Occasional decreased defecation and/or urination was observed at 15 and 20 mg/kg. No other adverse clinical signs were observed. Hair loss occurred in all doses including controls.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Mean body weight was decreased at ≥15 mg/kg on gestation days 9, 12, 16, 18, and 20. The decreases were statistically significant only on days 12, 16, and 18 at 20 mg/kg. Body weights at 1, 5, and 10 mg/kg were comparable to control.

An adverse effect on body weight gain appeared dose-related at dose of ≥5 mg/kg, primarily during the first 3 days of dosing. A statistically significant mean body weight loss was observed at 20 mg/kg during gestation days 6-9 and 9-12. Mean body weight gain remained inhibited in this group on gestation days 12-16 resulting in a statistically significant mean body weight loss on days 6-16 (treatment period). Similar body weight effects were observed in animals given 15 mg/kg. Statistically significant mean body weight loss was observed on gestation day 6-9, and gains remained slightly reduced on days 9-12 and 12-16 resulting in a statistically significant mean body weight loss on days 6-16 (treatment period). At both 15 and 20 mg/kg body weight gain was statistically increased on days 16-18, and was comparable to control on days 18-20. Slight, non-statistically significant body weight loss was observed at 5 and 10 mg/kg on gestation day 6-9, but mean body weight gains were comparable to control for the remainder of gestation. A slight decrease in mean body weight gain was observed for the days 6-16 (treatment period) at 10 mg/kg. No effects were observed at 1 mg/kg.

Food consumption and compound intake (if feeding study):

not examined

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

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

A non-statistically significant increase in mean thyroid weight (26% compared to control) was observed at 20 mg/kg.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

One animal at 1 mg/kg had a pitted kidney and one animal had white precipitate in kidney, ureter, and bladder. Dilated renal pelvis was observed in one animal at 1 mg/kg and one animal at 10 mg/kg. Evidence of intubation trauma was observed as red fluid and gelatinous red material in the thoracic cavity in one animal at 1 mg/kg.

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:

effects observed, treatment-related

Description (incidence and severity):

A slight, non-statistically significant, increase in postimplantation loss was observed at 20 mg/kg.

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 specified

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

Dose descriptor:

NOAEL

Effect level:

1 mg/kg bw/day

Basis for effect level:

body weight and weight gain

Fetal body weight changes:

effects observed, treatment-related

Description (incidence and severity):

A statistically significant decrease in foetal body weight was observed at ≥10 mg/kg.

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

External malformations:

effects observed, treatment-related

Description (incidence and severity):

Cleft palate was observed in 6 foetus from 2 litters at 20 mg/kg.

Skeletal malformations:

not examined

Visceral malformations:

not examined

Dose descriptor:

NOAEL

Effect level:

5 mg/kg bw/day

Basis for effect level:

other: Fetotoxicity: decrease in mean fetal weight at ≥10 mg/kg

Dose descriptor:

NOAEL

Effect level:

15 mg/kg bw/day

Basis for effect level:

other: teratogenicity: increased incidence of cleft palate at 20 mg/kg

Abnormalities:

effects observed, treatment-related

Localisation:

other: cleft palate at 20 mg/kg

Developmental effects observed:

yes

Lowest effective dose / conc.:

10 mg/kg bw/day

Treatment related:

yes

Relation to maternal toxicity:

developmental effects as a secondary non-specific consequence of maternal toxicity effects

Conclusions:

NOAEL for developmental toxicity is 5 mg/kg bw/day. NOAEL for maternal toxicity was 1 mg/kg bw/day. There were no indications for developmental toxicity in doses below maternal toxic doses.

Executive summary:

The ability of the test substance to cause maternal and developmental toxicity was evaluated. The test substance, suspended in corn oil, was administered to pregnant rats via gavage once daily on gestation days 6-15 at doses of 0, 1, 5, 10, 15, or 20 mg/kg. Throughout gestation the rats were observed for appearance and behaviour, and body weight were recorded. All animals were sacrificed on gestation day 20. The uteri and ovaries were examined and the number of foetuses, early and late resorptions, total implantations, and corpora lutea were recorded. The thyroid, kidneys, spleen, and liver of the females were weighed. Foetuses were weighed, sexed, and examined for external malformations or variations.

No mortality was observed. Maternal toxicity was observed at ≥5 mg/kg/day, expressed as a dose-related decrease in mean body weight gain. Developmental toxicity was observed at ≥10 mg/kg/day, expressed as a dose-related reduction in mean foetal body weight and the incidence of cleft palate in 6 foetuses at 20 mg/kg. The NOAELs are 1 mg/kg/day for maternal toxicity and 5 mg/kg/day for developmental toxicity.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

15 mg/kg bw/day

Study duration:

subacute

Species:

rat

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

The ability of the test substance to cause maternal and developmental toxicity was evaluated. The test substance, suspended in corn oil, was administered to pregnant rats via gavage once daily on gestation days 6-15 at doses of 0, 1, 5, 10, 15, or 20 mg/kg. Throughout gestation the rats were observed for appearance and behaviour, and body weight were recorded. All animals were sacrificed on gestation day 20. The uteri and ovaries were examined and the number of foetuses, early and late resorptions, total implantations, and corpora lutea were recorded. The thyroid, kidneys, spleen, and liver of the females were weighed. Foetuses were weighed, sexed, and examined for external malformations or variations. No mortality was observed. Maternal toxicity was observed at ≥5 mg/kg/day, expressed as a dose-related decrease in mean body weight gain. Developmental toxicity was observed at ≥10 mg/kg/day, expressed as a dose-related reduction in mean foetal body weight and the incidence of cleft palate in 6 foetuses at 20 mg/kg. The NOAELs are 1 mg/kg/day for maternal toxicity and 5 mg/kg/day for developmental toxicity.

Justification for classification or non-classification

Based on the available data, there is no indication that the test substances produced developmental toxicity at doses below those that caused maternal toxicity. Therefore, the test substance is not classified for developmental toxicity according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.