Triisononyl benzene-1,2,4-tricarboxylate

Endpoint summary

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Effects on fertility

Description of key information

The NOEL (No Observed Effect Level) for general systemic toxicity, fertility and reproduction parameters was 1000 mg/kg bw/day for males and females.

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2018-06-28 to 2018-09-08

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Version / remarks:

Adopted 2016-07-29

Deviations:

no

GLP compliance:

yes

Limit test:

no

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source: Production lot
- Lot/batch No.of test material: TM870
- Expiration date of the lot/batch: n/a

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Ambient conditions

Species:

rat

Strain:

Sprague-Dawley

Details on species / strain selection:

The rat was selected as the most appropriate species being that preferred by the test guidelines.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Germany, Sulzfeld, Germany
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: (P): 11 - 12 weeks
- Weight at study initiation: (P) Males: 375 - 428 g; Females: 251 - 302 g
- Fasting period before study: No
- Housing: Pre-mating: up to 5 of one sex/cage. Mating: 1 male/1 female/cage. Post-mating: males group caged; females individually caged
- Diet: commercially available rodent diet (Mucedola 4RF21) ad libitum
- Water: Municipal supply tap water ad libitum
- Acclimation period: 4 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24
- Humidity (%): 40 - 70
- Air changes (per hr): 15 - 20
- Photoperiod (hrs dark / hrs light): 12/12
IN-LIFE DATES: From: 2018-06-28 To: 2018-09-08

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

- PREPARATION OF DOSING SOLUTIONS:
The test item was formulated in the vehicle at concentrations of 25 mg/mL, 75 mg/mL and 250 mg/mL.

VEHICLE
- Justification for use and choice of vehicle: The substance is not soluble in water therefore corn oil was used for preparing formulations appropriate for oral administration.
- Concentration in vehicle: 25, 75 and 250 mg/mL
- Amount of vehicle: 4 mL/kg bw

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: up to 14 days
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as Day 0 of pregnancy
- After successful mating each pregnant female was caged how?: individually
- Any deviations from standard protocol: no

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytical control of formulations for concentration and homogeneity was performed twice during the study period.
Samples were taken from different places from each concentration for analysis of concentration and homogeneity. Similar sampling was undertaken from the vehicle control.
Measured concentrations were within the test facility acceptance criteria of 85 - 115% with CV < 10%.

Duration of treatment / exposure:

Males: 2 weeks prior to mating, during pairing, and continuing for a minimum of 28 days (29 days total)
Females: 2 weeks prior to mating, during pairing, continuing through gestation and parturition to 13 days post-partum (43 - 65 days total)

Frequency of treatment:

Once daily

Dose / conc.:

0 mg/kg bw/day (nominal)

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 males / 10 females

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Doses were selected with the aim of inducing toxic effects but no mortality or suffering at the highest dose and a NOAEL at the lowest dose.
- Rationale for animal assignment: random
- Fasting period before blood sampling for clinical biochemistry: n/a

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least daily
- Cage side observations included: mortality and clinical signs.

BODY WEIGHT: Yes
- Time schedule for examinations: Males - weekly. Females - weekly then on gestation Days 0, 7, 14 and 20, Days 1, 4, 7 and 13 post-partum

FOOD CONSUMPTION INTAKE:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Time schedule: weekly intervals

Oestrous cyclicity (parental animals):

Oestrus cyclicity was monitored by vaginal smears in:
- all stock females for at least 2 weeks before allocation in order to exclude females with irregular cycle.
- females allocated to study starting from Day 1 of dosing up to a positive identification of copulation.
- vaginal smears were also be taken from all study females on termination.

Sperm parameters (parental animals):

Parameters examined in male parental generations: testis weight, epididymis weight

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes
- If yes, maximum of 4 pups/sex/litter; excess pups were killed and discarded.

PARAMETERS EXAMINED
The following parameters were examined in offspring: number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities, anogenital distance (AGD), pup weight on the day of AGD, presence of nipples/areolae in male pups.

GROSS EXAMINATION OF DEAD PUPS: yes
- for external and internal abnormalities to establish, where possible, cause of death

ASSESSMENT OF DEVELOPMENTAL NEUROTOXICITY: no

ASSESSMENT OF DEVELOPMENTAL IMMUNOTOXICITY: no

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals after at least 28 days treatment
- Maternal animals: All surviving animals on Day 14 post-partum

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.

HISTOPATHOLOGY / ORGAN WEIGHTS
- Organ weights: Adrenal glands, Epididymides, Kidneys, Liver, Ovaries, Prostate gland, Seminal vesicles, Spleen, Testes, Thymus, Thyroid, Uterus.
- Tissues fixed and preserved: Abnormalities, Adrenal glands, Brain (cerebrum, cerebellum, medulla/pons), Clitoral gland, Epididymides, Kidneys, Liver, Mammary area (males and females), Ovaries, Oviducts, Parathyroid glands, Pituitary gland, Prostate gland, Sciatic nerve, Seminal vesicles, Spleen, Testes, Thymus (where present), Thyroid gland, Uterus – cervix, Vagina.

HISTOPATHOLOGY: Yes
Full histopathology was performed on the preserved organs or tissues of the animals of the control (Group 1) and high dose (Group 4) groups killed on termination of treatment. After dehydration and embedding in paraffin wax, sections were cut at 5 micrometre thickness and stained with haematoxylin and eosin.

Postmortem examinations (offspring):

SACRIFICE
- The offspring were sacrificed at 14 days of age.
- These animals were subjected to postmortem examinations (macroscopic and/or microscopic examination) as follows: external examination and sex confirmation by inspection of the gonads

Statistics:

For continuous variables such as body weight, food consumption, hormone determination and organ weight the significance of the differences amongst group means was assessed by Dunnett’s test or a modified t test, depending on the homogeneity of data.
Statistical analysis of histopathological findings was carried out by means of the non-parametric Kolmogorov-Smirnov test if n was more than 5.
The non-parametric Kruskal-Wallis analysis of variance was used for other parameters. Intergroup differences between the control and treated groups was assessed by the non-parametric version of the Williams test.

Reproductive indices:

Copulation Index: No. of pairs with successful copulation/no. of pairs mated X 100
Fertility Index: No of pregnant females/no. of pairs with successful copulation X 100
Pre-coital interval: No. of nights paired prior to detection of mating
Pre-implantation loss: No. of corpora lutea – no. implantation sites/no. of corpora lutea X 100
Pre-natal loss: No. of visible implantation sites – Live litter size/no. of implantation sites X 100

Offspring viability indices:

Post-natal loss: Live litter size at birth – live litter size at Day 4/live litter size at birth X 100

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Males: Body weight gain showed a statistically significant reduction on a single occasion (Day 8 of the pre-mating period) in males dosed at 1000mg/kg bw/day.
Females: Loss of body weight observed in females dosed at 300 and 1000 mg/kg bw/day on Day 8 of the pre-mating period. Reduced body weight noted in females treated at 300 and 1000 mg/kg bw/day on Day 8 of the pre-mating period. A slight but statistically significant dose-related reduction in body weight was noted starting from gestation Day 7 Day 4 post-partum. Recovery from these reductions gradually occurred. These were attributed to the earlier pre-mating weight loss.
The occasional nature of the body weight and body weight gain reductions in both males and females, and considering the slight impact on the group mean value, these changes were not considered to be adverse.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

No effects on food consumption were observed in males and females during the pre-mating period.
Statistically significant dose-related reductions in food consumption were observed in treated females, mainly on Days 7 and 14 post-coitum. These decreases, consistent with the observed reduced body weight gains, gradually recovered and they therefore were not considered to be adverse.

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

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

No treatment-related changes were noted. Those sporadic lesions that were observed were considered to be an expression of spontaneous/or incidental pathology, seen in this species and age or animal.

Spermatogenic cycle: Seminiferous tubules were evaluated with respect to their stage in the spermatogenic cycle and to the integrity of the various cell types within the different stages. Regular layering in the germinal epithelium was noted.

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Description (incidence and severity):

Thyroid hormone analysis: Individual males from all treatment groups showed an increase of thyroid stimulating hormone. Since no related changes of triiodothyronine and/or thyroxine were recorded, the above finding was considered to be incidental

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

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: Lack of significant treatment related 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

Anogenital distance (AGD):

no effects observed

Nipple retention in male pups:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No significant differences were observed in the weight of thyroid of treated pups, when compared to controls.

Gross pathological findings:

no effects observed

Other effects:

no effects observed

Description (incidence and severity):

Thyroid hormone analysis: Pups – Day 14 post- partum - One male and one female pup of parental animals treated at 1000 mg/kg bw/day showed high triiodothyronine values. Due to the minimal incidence and the absence of changes of the other examined hormones, this finding was considered to be incidental.

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

not examined

No treatment-related nor significant differences in total litter size, live litter size, mean pup loss (percentage), mean pup weights (percentage) and sex ratio of pups were observed among the treated and the control dams at birth and on Days 1, 4 and 13 post partum.

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: Lack of significant treatment related effects

Key result

Critical effects observed:

no

Key result

Reproductive effects observed:

no

Conclusions:

The NOEL (No Observed Effect Level) for general systemic toxicity, fertility and reproduction parameters was 1000 mg/kg bw/day for males and females.

Executive summary:

The toxic effects of triisononyl benzene-1,2,4-tricarboxylate, as well as any effects item on male and female reproductive performance, such as gonadal function, mating behaviour, conception, parturition and early lactation of the offspring have been investigated in Sprague Dawley rats after repeated oral exposure. Doses of 0, 100, 300 and 1000 mg/kg bw/day were administered and males were treated for 14 days prior to pairing, during pairing with females and for a total of 29 days. Females were treated for 14 days prior to pairing, during pairing and throughout the gestation and lactation periods until Day 13 post partum, for a total of 43 to 65 days.

Only minimal transitory treatment-related effects on body weight gain and food consumption were observed in males dose at 1000 mg/kg bw/day and in the treated females. These signs were not considered to be adverse, considering their low magnitude, occasional

nature and reversibility at the end of the mating (for males) and post partum periods (for females). No effects on male and female reproductive performance, such as gonadal function, mating behaviour, conception, parturition and early lactation of the offspring

were noted at any of the dose levels investigated.

The NOEL (No Observed Effect Level) for general systemic toxicity, fertility and reproduction parameters was therefore considered to be 1000 mg/kg bw/day for males and females.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

Experimental data are available from a reproductive toxicity screening study in the rat on the registered substance which investigated potential effects on male and female reproductive performance, such as gonadal function, mating behaviour, conception, parturition and early lactation of the offspring.

The NOEL (No Observed Effect Level) for general systemic toxicity, fertility and reproduction parameters was 1000 mg/kg bw/day for males and females.

Effects on developmental toxicity

Description of key information

NOEL maternal toxicity: 1130 mg/kg bw/day

NOEL pre-natal developmental toxicity: 1130 mg/kg bw/day

NOEL post-natal evaluation of offspring: 538 mg/kg bw/day; LOAEL: 1130 mg/kg bw/day (slight increase in retained areolar region in males treated at 1050 mg/kg/day post-natal Day 13, no longer present postnatal day 18 and slightly higher increase in displaced testes compared to controls although the observed incidence was within the range of historical control data).

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

HYPOTHESIS FOR THE ANALOGUE APPROACH
The source and target substances are both trimellitate esters differing only in the length of the side chains by a single carbon (C8 vs. C9). The common structure does not include any functional group of concern with regard to a specific mechanism of toxicity and, as a result, they are regarded as sharing a common mechanism of (lack of) action.

ANALOGUE APPROACH JUSTIFICATION
The source substance is tri(2-ethylhexyl)trimellitate (TOTM), a trimellitate ester with branched sidechains of C8 length, and the target substance is triisononyl trimellitate (TINTM), a trimellitate ester with branched sidechains of C9 length. Given the commonality of structure between the source and target substances and the lack of structural alerts within the two, it is reasonable that the experimental data available on the source substance, tri(2-ethylhexyl)trimellitate (TOTM), a trimellitate ester with branched sidechains of C8 length is indicative of the properties of triisononyl trimellitate (TINTM), a trimellitate ester with branched sidechains of C9 length.

Reason / purpose for cross-reference:

read-across source

Dose descriptor:

NOAEL

Effect level:

1 130 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: overall effects

Abnormalities:

no effects observed

Dose descriptor:

NOAEL

Effect level:

1 130 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Lack of significant effects on foetuses

Remarks on result:

other: Pre-natal developmental toxicity

Dose descriptor:

NOEL

Effect level:

538 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Retained areolar region PND 13, no longer present PND 18

Remarks on result:

other: Post-natal developmental toxicity

Dose descriptor:

LOAEL

Effect level:

1 130 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Retained areolar region PND 13, no longer present PND 18

Remarks on result:

other: Post-natal developmental toxicity

Abnormalities:

no effects observed

Developmental effects observed:

no

Lowest effective dose / conc.:

1 130 mg/kg bw/day (nominal)

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 130 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

Experimental data are available on a structurally similar trimellitate, tri(2 -ethylhexyl)trimellitate (TOTM), which differs from the registered substance only in the length of the ester side chaines (branched C8 vs. branched C9).

This developmental toxicity study in the rat, extended to permit an assessment of post-natal development, found no treatment-related effects indicative of maternal toxicity. No effects on offspring body weights or litter viability were observed. No developmental (teratogenic) effects were observed and there were no effects upon sexual maturation or development of the reproductive tract in male or female offspring that were attributed to treatment.

NOEL maternal toxicity: 1050 mg/kg/day (1130 mg/kg/day accounting for differences in molecular weight)

NOEL pre-natal developmental toxicity: 1050 mg/kg/day (1130 mg/kg/day accounting for differences in molecular weight)

NOEL post-natal evaluation of offspring: 500 mg/kg/day; LOAEL: 1050 mg/kg/day (slight increase in retained areolar region in males treated at 1050 mg/kg/day post-natal Day 13, no longer present postnatal day 18 and slightly higher increase in displaced testes compared to controls although the observed incidence was within the range of historical control data). (538 mg/kg/day and 1130 mg/kg/day, respectively, accounting for differences in molecular weight)

Justification for classification or non-classification

According to EU Directive 67/548/EEC and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008, classification and labelling is not indicated for reproductive toxicity as adverse effects on sexual function and fertility in adult males and females or evidence of developmental toxicity in offspring have not been observed.