Registration Dossier

Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
12 December 2017 - 12 February 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: OECD 422 Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test
Deviations:
no
GLP compliance:
yes (incl. certificate)
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Specific details on test material used for the study:
Identification: Sodium 2,4,5-trichlorobenzenesulphonate
CAS number: 53423-65-7
Acronym: STB-FR
Molecular formula: C6H2Cl3O3S.Na
Molecular weight: 283.494
Appearance: White powder
pH: 6.9 (5% aqueous slurry)
Batch: 1708-02
Purity/Composition: >99%
Stable under storage conditions until: 31 December 2018 (expiry date)

Test animals

Species:
rat
Strain:
Wistar
Details on test animals and environmental conditions:
The Wistar Han rat was chosen as the animal model for this study as it is an accepted rodent species for toxicity testing by regulatory agencies. The test laboratory has general and reproduction/developmental historical data in this species from the same strain and source. This animal model has been proven to be susceptible to the effects of reproductive toxicants.

Administration / exposure

Route of administration:
oral: gavage
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Frequecy: Once during week 1 of dosing
Dose Groups Tested: Concentration: All Groups; Homogeneity: Groups 2 and 4
Method: LC-DAD (Method Validated by Analytical Biochemical Laboratory B.V. (ABL)
Stability of Test Substance in Vehicle: Verified to be stable during method development
Details on mating procedure:
After 14 days of treatment, animals were cohabitated on a 1:1 basis within the same treatment group, avoiding sibling mating. Detection of mating was confirmed by evidence of sperm in the vaginal lavage or by the appearance of an intravaginal copulatory plug. This day was designated Day 0 post-coitum. Once mating had occurred, the males and females were separated. A maximum of 14 days was allowed for mating, after which females who have not shown evidence of mating were separated from their males.
Duration of treatment / exposure:
Males: 29 days up to and including the day before scheduled necropsy. This included a minimum of 14 days prior to mating and during the mating period.
Females that failed to deliver: 41-51 days
Females that delivered: 50 - 62 days; i.e. 14 days prior to mating (with the objective to cover at least two complete estrous cycles), the variable time to conception, the duration of pregnancy and at least 13 days after delivery, up to and including the day before scheduled necropsy.
Frequency of treatment:
Once daily, 7 days per week.
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day (nominal)
Remarks:
Vehicle only
Dose / conc.:
100 mg/kg bw/day (nominal)
Dose / conc.:
300 mg/kg bw/day (nominal)
Dose / conc.:
1 000 mg/kg bw/day (nominal)
No. of animals per sex per dose:
10
Control animals:
yes, concurrent vehicle

Examinations

Maternal examinations:
Mortality/ moribundity: Twice daily, in the morning and at the end of the working day
Clinical signs: Once daily, beginning during the first administration of the test item and lasting throughout the dosing periods up to the day prior to necropsy
Functional observations (for 5 selected animals/sex/group; hearing, pupillary reflex, static righting reflex, strength, locomotor activity): Males: week 4 of treatment; Females: during last week of lactation (PND 6 - 13).
Body weight: Weekly
Food consumption: Days 0, 4, 7, 11, 14, 17, and 20 post-coitum and during lactation on post natal day (PND) 1, 4, 7, and 13
Estrous cycle determination: All femails daily begining 13 days prior to treatment, the first 14 days of treatment, and during mating until evidence of copulation was observed.
Clinical pathology (for 5 selected animals/sex/group): Blood was collected once on the day of scheduled necropsy and included typical hematology and clinical chemistry parameters.
Ovaries and uterine content:
Ovaries: weight as well as macroscopic and mictroscopic abnormalities
Uterine content: Number of implantation sites.
Fetal examinations:
Early postnatal pup development consisting of mortality, clinical signs, body weight, anogenital distance, areola/nipple retention, T4 thyroid hormone levels and macroscopic examination.
Indices:
Gestation, viability and lactation indices, duration of gestation, parturition, sex ratio, maternal care

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
no effects observed
Mortality:
mortality observed, non-treatment-related
Description (incidence):
Female no. 52 (100 mg/kg) died at blood sampling before necropsy on Lactation Day 14. There were no test item-related macroscopic or microscopic findings in the organs examined for this animal. This accidental death was attributed to the blood sampling procedure, and as such not considered to be related to treatment with the test item.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Slight, non-adverse, changes in body weight were noted for males and females at 1000 mg/kg.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
Slight, non-adverse, changes in food intake were noted for males and females at 1000 mg/kg.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
no effects observed
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
- Higher alanine aminotransferase activity (ALAT) in males at 300 and 1000 mg/kg (1.5x higher than control values; means outside historical control range).
- Higher aspartate aminotransferase activity (ASAT) in males at 300 and 1000 mg/kg (1.3x and 1.5x higher than control values, respectively; means within historical control range).
- Higher urea in males and females at 1000 mg/kg (2.0x and 1.2x of control, respectively; mean outside historical control range).
- Higher creatinine in males at 1000 mg/kg (1.7x higher than control; mean outside historical control range).
- Lower potassium in males at 1000 mg/kg (0.9x of control; mean outside historical control range).
- Lower mean total bilirubin in females at 1000 mg/kg (0.8x of control; mean within historical control range).
- Higher cholesterol in females at 1000 mg/kg (1.3x of control; mean within historical control range).
- Lower serum levels of T4 in F0 males at 1000 mg/kg. Levels were 0.5x lower than control values. For three males at 1000 mg/kg (nos. 31, 33 and 36), the T4 value was below the detection limit of 1.00 ug/dL.
Urinalysis findings:
not examined
Behaviour (functional findings):
no effects observed
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
There was an apparent test item-related decrease in thymus weight in males at 100, 300 and 1000 mg/kg and in females at 300 and 1000 mg/kg, but this was only significant in males treated at 1000 mg/kg/day (absolute). In addition, there was a test item-related increase in kidney weight in males treated at 1000 mg/kg/day (absolute and relative to body weight).
Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
Test item-related macroscopic findings were present in males treated at 1000 mg/kg/day in the kidneys as pale discolouration in 5/10 rats and in the thymus as reduced in size in 1/10 rat.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
effects observed, treatment-related
Description (incidence and severity):
Test item-related microscopic findings after treatment with STB-FR were noted in the urinary bladder, kidneys, thymus and stomach of both males and females. Urothelial hypertrophy of the urinary bladder was present in males at 300 and 1000 mg/kg (up to moderate degree) and in females at 1000 mg/kg (up to slight degree). An increased incidence and/or severity of tubular basophilia in the kidneys was present in males at 1000 mg/kg (up to moderate degree) and in females at 300 and 1000 mg/kg (up to slight degree). Renal casts were present at increased incidence and severity in males at 1000 mg/kg (up to slight degree). Renal tubular dilation was present at increased incidence and severity in males and females at 1000 mg/kg (up to marked and slight degree, respectively). For males, tubular dilation correlated with the macroscopic pale discolouration and with the increase in kidneys weight. Lymphoid depletion in the thymus was present at minimal degree in females at 300 and 1000 mg/kg and in males at 1000 mg/kg. For males, this correlated with the macroscopic reduction in size and with the decrease in thymus weight. Squamous cell hyperplasia of the limiting ridge of the stomach was present at minimal degree in males and females at 1000 mg/kg.
Other effects:
no effects observed

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:
effects observed, non-treatment-related
Description (incidence and severity):
One pup each at 100, 300 and 1000 mg/kg (from dam nos. 55, 66 and 75, respectively) were found dead at first litter check. No toxicological relevance was attributed to these dead pups since the mortality incidence did not show a dose-related trend and remained within the range considered normal for pups of this age
Changes in pregnancy duration:
no effects observed
Changes in number of pregnant:
no effects observed
Other effects:
no effects observed

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
maternal abnormalities
number of abortions
pre and post implantation loss
total litter losses by resorption
effects on pregnancy duration
early or late resorptions
dead fetuses
changes in pregnancy duration
changes in number of pregnant
necropsy findings

Results (fetuses)

Fetal body weight changes:
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
Changes in postnatal survival:
no effects observed
External malformations:
no effects observed
Skeletal malformations:
no effects observed
Visceral malformations:
not examined
Other effects:
no effects observed
Details on embryotoxic / teratogenic effects:
No embryotoxic / teratogenic effects were observed in this screening study.

Effect levels (fetuses)

Key result
Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
reduction in number of live offspring
changes in sex ratio
fetal/pup body weight changes
changes in litter size and weights
changes in postnatal survival
external malformations
skeletal malformations

Overall developmental toxicity

Key result
Developmental effects observed:
no

Applicant's summary and conclusion

Conclusions:
A NOAEL of >= 1000 mg/kg was established based on the absence of any adverse developmental effects at the highest dose tested. Given these results, the substance does not meet the GHS criteria for classification under the criteria for developmental toxicity.
Executive summary:

In this GLP Combined 28-Day Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test, conducted in accordance with OECD guideline 422 with male and female Wister (Han) rats by oral gavage at doses of 0 (vehicle only), 100, 300, and 1000 mg/kg-bw/day, a NOAEL of 1000 mg/kg-bw/day was established for developmental toxicity based on the absence of any adverse developmental effects at the highest dose tested. Given these results, the substance does not meet the GHS criteria for classification under the criteria for developmental toxicity.