[No public or meaningful name is available]

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

No adverse reproductive toxicity effects

Link to relevant study records

Reference

Endpoint:

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

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: guideline study with modifications, under GLP

Justification for type of information:

An analogue approach is used for the hazard assessment of several human health endpoints. The hypothesis for the analogue approach is that data can be read-across from data-rich substances, namely acetyl tributyl citrate (ATBC, CAS 77-90-7), acetyl triethyl citrate (CAS 77-89-4) and triethyl citrate (TEC, CAS 77-93-0) to acetyl trihexyl citrate (ATHC, CAS 24817-92-3). The analogue approach is based on common breakdown products via physical and biological processes, and similar functional groups, according to Annex XI, Section 1.5, of Regulation EC No. 1907/2006. Read-across to ATHC is indicated in order to avoid unnecessary in vivo testing according to Article 25 of Regulation EC No. 1907/2006.
The analogue approach to evaluating the safety of triethyl citrate is adopted here, reflecting the approach used by various expert panels and authoritative bodies in their safety assessment of TEC, included JECFA, EFSA, U.S. FDA, EPA and CIR. The use of analogues for hazard evaluation is justified (Scenarios 1 and 2 of the RAAF, 2015) because the substances have common breakdown products via physical and biological processes, which reflects the similar functional groups in their chemical structure. The proposed analogues have similar functional groups, including: a citric acid (tricarboxylic acid) backbone, three short-chain alkyl esters, and an acetyl group (except for TEC). Other than the acetyl group, there are no other functional groups which may introduce additional toxicities. The substances display similar classification based on similar toxicities.
The target substance is expected to have essentially the same effect in the toxicity test/endpoint as does the source substance. Dose descriptors obtained for derivation of a DNEL are adequate and appropriate, and do not underestimate the hazards of the registered substance.
This information is adequate to fulfill the data requirements of Annex IX, to be the basis for classification and labelling decisions, and for risk assessment.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: OECD 408 with in utero phase

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

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

Species:

rat

Strain:

Wistar

Sex:

male/female

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

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:

25

Control animals:

yes, plain diet

Positive control:

no

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

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: 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.

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.

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

Key result

Critical effects observed:

no

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

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.

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

Key result

Critical effects observed:

no

Key result

Reproductive effects observed:

no

Conclusions:

A dietary toxicity study was undertaken to the analogue ATBC 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 and target substance 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.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

adequate

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

No teratogenic effects

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: guideline study under GLP

Justification for type of information:

An analogue approach is used for the hazard assessment of several human health endpoints. The hypothesis for the analogue approach is that data can be read-across from data-rich substances, namely acetyl tributyl citrate (ATBC, CAS 77-90-7), acetyl triethyl citrate (CAS 77-89-4) and triethyl citrate (TEC, CAS 77-93-0) to acetyl trihexyl citrate (ATHC, CAS 24817-92-3). The analogue approach is based on common breakdown products via physical and biological processes, and similar functional groups, according to Annex XI, Section 1.5, of Regulation EC No. 1907/2006. Read-across to ATHC is indicated in order to avoid unnecessary in vivo testing according to Article 25 of Regulation EC No. 1907/2006.
The analogue approach to evaluating the safety of triethyl citrate is adopted here, reflecting the approach used by various expert panels and authoritative bodies in their safety assessment of TEC, included JECFA, EFSA, U.S. FDA, EPA and CIR. The use of analogues for hazard evaluation is justified (Scenarios 1 and 2 of the RAAF, 2015) because the substances have common breakdown products via physical and biological processes, which reflects the similar functional groups in their chemical structure. The proposed analogues have similar functional groups, including: a citric acid (tricarboxylic acid) backbone, three short-chain alkyl esters, and an acetyl group (except for TEC). Other than the acetyl group, there are no other functional groups which may introduce additional toxicities. The substances display similar classification based on similar toxicities.
The target substance is expected to have essentially the same effect in the toxicity test/endpoint as does the source substance. Dose descriptors obtained for derivation of a DNEL are adequate and appropriate, and do not underestimate the hazards of the registered substance.
This information is adequate to fulfill the data requirements of Annex IX, to be the basis for classification and labelling decisions, and for risk assessment.

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD 408 modified

Qualifier:

equivalent or similar to guideline

Guideline:

other: US EPA OPPTS 870.3100 modified

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

no analysis of uterine contents GD 20

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD 433 EOGRTS

Version / remarks:

without extentions

Principles of method if other than guideline:

Four week repeated dose exposure to adult rats prior to mating, with gravid females exposed during gestation and weaning (6 weeks).

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

Wistar Han rats

Route of administration:

oral: feed

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytical verification occurred; doses were not lower than target doses.

Details on mating procedure:

Males and females cohabitated and mated (1 week).

Duration of treatment / exposure:

P males and females were treated for four weeks prior to mating until scheduled sacrifice. They cohabitated and mated (1 week). After mating, males were sacrificed and toxicity was assessed . Females (P) were placed in separate cages and allowed to deliver, nurse and wean offspring, and then sacrificed. The F1 offspring were placed on test diets for 13 weeks. after which aa recovery groups was test material free for 4 weeks.

Frequency of treatment:

daily in feed

Duration of test:

24 weeks (EOG) plus 4 weeks recovery

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:

25

Control animals:

yes, plain diet

Details on study design:

At the completion of the in utero phase, F1 rats that had been exposed to test material from 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.

Maternal examinations:

Parental animals were evaluated for reproductive endpoints (mating performance, fertility, gestation length and parturition, litter size, numbers of implantations, survival and growth), and F1 animals were evaluated for sexual maturation (balano-preputial separation, vaginal opening, anogenital distance, retained areolae in males, sperm assessments), estrous cyclicity, physical appearance, ophthalmologic effects, neurobehavioral effects, growth, food consumption, survival, hematology, blood chemistry, urinalysis, peroxisome proliferation, organ weights, gross pathology and histopathology. A full range of tissues were retained for theP 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 P males and females, as well as tissues found to be abnormal at necropsy.

Ovaries and uterine content:

Animals allowed to deliver litters naturally.

Fetal examinations:

F1 animals were evaluated for sexual maturation (balano-preputial separation, vaginal opening, anogenital distance, retained areolae in males, sperm assessments), estrous cyclicity, physical appearance, ophthalmologic effects, neurobehavioral effects, growth, food consumption, survival, hematology, blood chemistry, urinalysis, peroxisome proliferation, organ weights, gross pathology and histopathology. A full range of tissues were retained for the Pyes males and females and reproductive organ tissues were retained for F1 males and females.

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.

Historical control data:

yes

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Yellow staining of the perigenital and perianal areas of high dose females

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

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry 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

Gross pathological findings:

no effects observed

Neuropathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Details on results:

Maternal toxic effects:no effects. 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.

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

Changes in number of pregnant:

no effects observed

Other effects:

no effects observed

Description (incidence and severity):

Oestrous cycles, mating performance and fertility were unaffected by four weeks of exposure to tet material at dietary concentrations targeted to generate an intake of 1000 mg/kg/day.

Details on maternal toxic effects:

Maternal toxic effects:no effects. 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.

Details on maternal toxic effects:
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.

After 13 weeks of treatment, high bodyweight-relative liver weights were recorded for males and females that received 1000 mg/kg/day. This resolved on completion of the Recovery period.

Anogenital distance in both sexes and retention of areolar regions in male offspring were unaffected
by treatment.

There were no macroscopic findings at necropsy of the F0 adults or surplus F1 offspring that were
attributable to treatment.

Key result

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: no effects

Key result

Abnormalities:

no effects observed

Fetal body weight changes:

not examined

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:

not examined

Visceral malformations:

not examined

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
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. There were no findings at necropsy of surplus offspring that were considered to be treatment-related.

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: no effects

Key result

Abnormalities:

no effects observed

Key result

Developmental effects observed:

no

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 and the target substance 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.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

adequate

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Mode of Action Analysis / Human Relevance Framework

Not applicable

Justification for classification or non-classification

In a well-designed study (EOGRTS format) to investigate repeated dose toxicity as well as reproductive toxicity, ATBC was given in the feed to Wistar rats and toxicity assessed. There were no adverse reproductive or developmental effects and the NOAEL was 1000 mg/kg bw/d. These data are applicable to the target substance and are adequate for risk assessment and classification and labelling.