[No public or meaningful name is available]

Toxicity to reproduction

Administrative data

Endpoint:

extended one-generation reproductive toxicity - basic test design (Cohorts 1A, and 1B without extension)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: guideline study with modifications, under GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: OECD 408 with in utero phase

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Test guideline 3

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 443 (Extended One-Generation Reproductive Toxicity Study)

Principles of method if other than guideline:

13 week repeated dose study using animals which were exposed in utero

GLP compliance:

yes

Limit test:

no

Justification for study design:

Extension of cohort 1 not necessary. Cohorts 2 and 3 not necessary as these are outside the scope of the requirements.

Test material

Test material information

Constituent 1

Reference substance name:

Tributyl O-acetylcitrate

EC Number:

201-067-0

EC Name:

Tributyl O-acetylcitrate

Cas Number:

77-90-7

Molecular formula:

C20H34O8

IUPAC Name:

tributyl 2-acetoxypropane-1,2,3-tricarboxylate

Test material form:

liquid

Remarks:

clear, oily

Details on test material:

Acetyltributyl citrate, batch # 0000016315, Expiry date: January 2002

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Administration / exposure

Route of administration:

oral: feed

Vehicle:

other: feed

Details on exposure:

F0 males and females were treated for four weeks prior to mating until scheduled sacrifice. The F1 male and female offspring were exposed in utero and from birth until the start of the 13-week study. The F1 offspring selected for the 13-week study were then provided the respective treated diets for 13-weeks.

Details on mating procedure:

Males and females cohabited for 1 week

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

P generation females were exposed to the diet during mating, gestation, littering and weaning. FI animals continued on the diet for 13 weeks.

Frequency of treatment:

daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

300 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

25

Control animals:

yes, plain diet

Positive control:

no

Examinations

Parental animals: Observations and examinations:

Parental animals were evaluated for reproductive endpoints (mating performance, fertility, gestation length and parturition, litter size, numbers of implantations, survival and growth).. A full range of tissues were retained for the F0 males and females and reproductive organ tissues were retained for F1 males and females. Microscopic examinations were performed on a standard set of tissues for F0 males and females, as well as tissues found to be abnormal at necropsy.

Oestrous cyclicity (parental animals):

yes

Sperm parameters (parental animals):

yes

Litter observations:

yes

Postmortem examinations (parental animals):

yes

Postmortem examinations (offspring):

yes

Statistics:

For organ weights and body weight changes, homogeneity of variance was tested using Bartlett’s test followed by Behrens-fisher test or Dunnett’s test as appropriate. Macroscopic pathology and histopathology data were assessed using Fisher’s Exact test. Estrus cycles were analyzed using the Cochran-Armitage trend test. Other statistical tests used as appropriate were: Williams’ test for a dose-related response; Student’s t-test; Shirley’s non-parametric test for a dose-related response; Steel’s test; and Wilcoxon rank sum test. Significance level was p<0.05.

Reproductive indices:

yes, in intact females carrying to term

Offspring viability indices:

yes

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

no effects observed

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:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

Description (incidence and severity):

There were no significant intergroup differences in the bodyweights of animals at the start of the 13 week toxicity study, and each toxicity and recovery phase group was composed of unrelated male and female siblings.

Details on results (P0)

Bodyweight and bodyweight gain, food consumption and the efficiency of food conversion of the P generation animals before pairing and of females during gestation and lactation were unaffected. Food consumption tended to be slightly lower than predicted, resulting in achieved chemical intakes
being 87-89% of target for males and 93-96% of target for females.

There was no effect of treatment upon the F1 generation before they were assigned to the Toxicity phase of this study at approximately four
weeks of age. The general condition of parental animals was unaffected by treatment. There were no macroscopic findings at necropsy of the P adults or surplus F1 offspring that were
attributable to treatment.Estrous cycles, mating performance, fertility, gestation length and parturition, were all unaffected by treatment. Litter size, survival and growth were similar in all groups and within expected historical control ranges. Although numbers of implantations and litter size at 1000 mg/kg/day were marginally lower than concurrent control group levels, they were within the laboratory’s historical control ranges. Anogenital distance and sexual maturation in both sexes and retention of areolae in male offspring were unaffected by treatment. There were no adverse effects on sperm motility, counts or morphology.

Effect levels (P0)

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:

other: NOAELs as published in the study report were reevaluated by US. EPA to be as described above.

Remarks on result:

not determinable due to absence of adverse toxic effects

Target system / organ toxicity (P0)

Key result

Critical effects observed:

no

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

Description (incidence and severity):

There were no significant intergroup differences in the bodyweights of animals at the start of the 13 week toxicity study

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:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings:

no effects observed

Details on results (F1)

There were no significant intergroup differences in the bodyweights of animals at the start of the 13 week toxicity study. There were no findings at necropsy of surplus F1 offspring that were considered to be treatment-related. At the completion of the in utero phase, rats that had been exposed to ATBC from before conception, through gestation and continuously from the time of birth, were selected (20 unrelated males and 20 unrelated females per dose group for the main study; and 10 unrelated males and 10 unrelated females for the control and high dose recovery groups) and transferred to the 13-week study.

Effect levels (F1)

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no effects

Target system / organ toxicity (F1)

Key result

Critical effects observed:

no

Overall reproductive toxicity

Key result

Reproductive effects observed:

no

Applicant's summary and conclusion

Conclusions:

A dietary toxicity study of ATBC was undertaken in weanling F1-generation Han Wistar male and female rats which had been exposed to the test material during gestation and weaning. The parental generation of these rats (P) had been exposed to this substance for 4 weeks prior to mating and 1 week during cohabitation. Doses were 100, 300 and 1000 mg/kg bw/d. There were no adverse effects observed in reproductive indices or in gross and histopathology in the P generation. There were no significant effects on sperm development or oestrus cycles. There were no adverse effects observed in gestation length, parturition, litter size, survival or growth of offspring. Necropsies of surplus offspring showed no adverse effects. The NOAEL for reproduction and for developmental toxicity was 1000 mg/kg bw/d. Data can be read-across between the structural analogues based on common breakdown products. This is adequate to fulfill the information requirements, to be the basis for classification and labelling decisions, and for risk assessment.