Registration Dossier

Diss Factsheets

Administrative data

Key value for chemical safety assessment

Effects on fertility

Description of key information

Screening for reproductive / developmental toxicity (OECD 422, read across from structural analogue TDP) - no signs of reproduction/developmental toxicity at doses up to 1000 mg/kg bw/day.

Link to relevant study records
Reference
Endpoint:
screening for reproductive / developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose for cross-reference:
reference to same study
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Deviations:
yes
Remarks:
See Principles of Method
Principles of method if other than guideline:
The study exceeded the OECD 422 guideline design by extending dosing of F0 females through Day 21 of lactation (total of 8-9 weeks). The original study design included evaluation of 28 day exposure in females (to correlate with 28 day exposure in males), male and female recovery groups, and extended post weaning evaluation (70 days) in F1 offspring. The final study report contains all sections required by the OECD 422 guideline (1996), including data collected on the FO parental animals and on the Fl offspring to their weaning on pnd 21 (an extension beyond the specified termination on pnd 4 in the OECD 422 [1996] testing guideline). The data collected on the 28-day females, the recovery males and females, and on the F1 offspring animals after weaning were collected as initially specified in the protocol but were not included in the study report. The data not reported (and wet tissues, blocks and slides not processed or examined) were retained in the study records and archived with the study upon the submission of the final report.
GLP compliance:
yes
Limit test:
yes
Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS - Source: Charles River Breeding Laboratories, Raleigh, NC - Age at study initiation: 10 weeks - Housing: The animals were individually housed upon arrival, during the acclimation period, and upon the initiation of the treatment period in solid-bottom polycarbonate cages with stainless-steel wire lids (Laboratory Products, Rochelle Park, NJ) with Sani-Chip® cage litter (P.J. Murphy Forest Products Corp., Montville, NJ). Study animals were housed 2 per cage (1 male: 1 female from the same dose group) during the mating period. Females were caged individually once they were successfully mated (or at the end of the mating period) and throughout gestation. Females were housed with their litters throughout the lactation period. Randomly selected Fl weanlings (10/sex/group), males, and females were singly housed during the postweaning exposure period. - Diet (e.g. ad libitum): Pelleted Purina Certified Rodent Diet® (No. 5002, PMI Feeds, Inc., St. Louis, MO was available ad libitum. - Water (e.g. ad libitum): Tap water (source: City of Durham, Department of Water Resources, Durham, NC) was available ad libitum in plastic water bottles with butyl rubber stoppers and stainless-steel sipper tubes. - Acclimation period: 1 week ENVIRONMENTAL CONDITIONS - Temperature (°C): 71.1 to 76.2°F - Humidity (%): 37.2% to 69.6%. - Photoperiod (hrs dark / hrs light): 12-hour light cycle per day
Route of administration:
oral: gavage
Vehicle:
corn oil
Details on exposure:
Male and female CD (Sprague-Dawley(SD)) F0 rats were administered TDP orally by gavage at 0, 50, 250 and 1000 mg/kg/day at a dose volume of 5 ml/kg/day in Mazola® corn oil, 10 animals/sex/dose, for 2 weeks of prebreed exposure (males and females), 2 weeks of mating (males and females) and 3 weeks of gestation and lactation each (F0 females).
Details on mating procedure:
After the 2-week prebreed exposure period, animals were randomly mated within treatment groups for a 2-week mating period to produce the F1 generation, with continuing exposure.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Homogeneity and stability studies were run on TDP in corn oil at concentrations of 10, 50, and 200 mg/mL (TDP in corn oil). The 50 and 200 mg/mL concentrations were prepared weekly as they were found to be stable. The 10 mg/mL concentration was prepared daily due to stability concerns. Dosage formulations analyzed during the study were found to be 90.8-110% of nominal concentrations.
Duration of treatment / exposure:
F0 males - 28 daysF0 females - 8-9 weeks (14 days prebreed, mating, gestation, lactation through pnd 21)
Frequency of treatment:
Once per day
Details on study schedule:
- Age at mating of the mated animals in the study: 12 weeks
Remarks:
Doses / Concentrations:0, 50, 250 and 1000 mg/kg/dayBasis:actual ingested
No. of animals per sex per dose:
10
Control animals:
yes, concurrent vehicle
Positive control:
No
Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes - Time schedule: at least once daily for F0 males and females until necropsy. DETAILED CLINICAL OBSERVATIONS: Yes - Time schedule: baseline during quarantine and then weekly BODY WEIGHT: Yes - Time schedule for examinations: Males - on study Day 0, then weekly and at necropsy; Females - on study Days 0, 7, and 14 (prebreed), and on Gesation Days 0, 7, 14, and 20, and on Lactation Days 0, 4, 7, 14 and 21. FOOD CONSUMPTION: Yes, at the same intervals as body weight. HAEMATOLOGY: Yes - Time schedule for collection of blood: Males - Day 28; Females - Day 13 - Animals fasted: Yes - How many animals: 5 per sex per group CLINICAL CHEMISTRY: Yes (males only) - Time schedule for collection of blood: Day 28 - Animals fasted: Yes - How many animals: 5 males per group URINALYSIS: Yes (males only) - Time schedule for collection of urine: Day 28 - Metabolism cages used for collection of urine: Yes NEUROBEHAVIOURAL EXAMINATION: Yes - Time schedule for examinations: FOB conducted prior to dosing and then weekly unti necropsy. Motor activity, auditory startle response and grip strength conducted at study termination (Day 28 for males; Week 8-9 for females) - Dose groups that were examined: All groups
Oestrous cyclicity (parental animals):
No
Sperm parameters (parental animals):
No
Litter observations:
All Fl pups were individually counted, sexed, weighed, and examined grossly at birth. Anogenital distance was measured and body weights recorded for all live F1 pups in all litters. F1 litters were culled on pnd 4 to yield as nearly as possible 5 males and 5 females per litter. The culled F1 pups were weighed, euthanized, and necropsied with complete external and visceral examinations. Any Fl pup that appeared moribund or that died during lactation was necropsied, when possible, to investigate the cause of death and to identify any internal visceral developmental malformations.
Postmortem examinations (parental animals):
GROSS PATHOLOGY: Yes, on all animals HISTOPATHOLOGY: Yes, on 5 control and 5 high dose males and females
Postmortem examinations (offspring):
Fl weanlings not selected for further study (data not reported) were subjected to a complete gross necropsy (external and visceral) examination, with gross lesions retained in 10% neutral buffered formalin.
Statistics:
The unit of comparison was the male, female, pregnant female, or the litter, as appropriate. Treatment groups were compared to the concurrent control group using either parametric ANOVA under the standard assumptions or robust regression method, which do not assume homogeneity of variance or normality. The homogeneity of variance assumption was examined via Levene's Test. If (p<0.05), robust regression methods were used to test all treatment effects, which use variance estimators that make no assumptions regarding homogeneity of variance or normality of the data. If Levene's Test did not reject the hypothesis of homogeneous variances, standard ANOVA techniques were applied for comparing the treatment groups. The GLM procedure in SAS® Release 8 was used to evaluate the overall effect of treatment and, when a significant treatment effect was present, to compare each exposed group to the control via Dunnett's Test. A one-tailed test (i.e., Dunnett's Test) was used for all pairwise comparisons to the vehicle control group, except that a two-tailed test was used for parental and pup body weight and organ weight parameters, feed consumption, percent males per litter, and anogenital distance. Student's t-test was used for analysis ofbody weight and organ weights from the recovery males and females and the 28-day females. All indices were analyzed by Chi-Square Test for Independence. When Chi-Square revealed significant (p<0.05) differences among groups, then a Fisher's Exact Probability Test, with adjustments for multiple comparisons, w':!s used for pairwise comparisons between each treatment group value and the control group value. Acquisition of developmental landmarks as well as anogenital distance, was also analyzed by Analysis of Covariance. For correlated data SUDAAN® software (RTI, 2001) was used for analysis of overall significance and pairwise comparisons to the control group values.
Reproductive indices:
FO mating, fertility, gestational, and pregnancy indices. The precoital interval and gestational length.Number of total implantation sites per litter and number of total and live pups per litter at birth.Percent postimplantation loss per litter
Offspring viability indices:
Live birth and stillbirth indices.Sex ratio per litter.Survival indices were calculated on pnd 0, 4, 7, and 14 and at weaning.
Clinical signs:
no effects observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Reproductive performance:
no effects observed
TDP, administered by gavage once daily at 0, 50, 250, 1000 mg/kg/day to parental FO CD® (SD) rats, 10/sex/group, through prebreed, mating, gestation, and lactation, resulted in essentially no treatment- or dose-related adult FO parental toxicity at any dose at any time.
Key result
Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No effects
Remarks on result:
not determinable due to absence of adverse toxic effects
Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Description (incidence and severity):
increases in epididymal weights were not considered adverse
Gross pathological findings:
no effects observed
There was no evidence of Fl offspring toxicity either at birth or during lactation. There were no effects on survival indices, litter size, sex ratio/litter, or pup deaths across any groups. Body weights of pups per litter (all pups or separately by sex) were equivalent across all groups for all time points, except for significant increases in female and all pup (but not male pup) body weights/litter at 50 mg/kg/day on pnd 0, most likely due to the slightly reduced live litter size (13.1) at this dose relative to the control live litter size (15.8). There were no effects on anogenital distance for either sex at birth. There were also no effects on absolute or relative organ weights in Fl males except for significant increases in absolute and relative (to body and brain weights) paired epididymal weights at 1000 mg/kg/day and epididymal weights (absolute and relative to brain but not body weights) at 250 mg/kg/day. There were no changes in any absolute or relative organ weights in Fl females. There were no treatment- or dose-related gross findings at necropsy of the Fl male or female pups on pnd 21.
Key result
Dose descriptor:
NOAEL
Generation:
F1
Effect level:
>= 1 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No effects
Remarks on result:
not determinable due to absence of adverse toxic effects
Reproductive effects observed:
not specified
Conclusions:
TDP administered by gavage once daily at 0, 50, 250 and 1000 mg/kg/day to parental F0 CD (SD) rats, 10/sex/group through prebreed, mating, gestation and F1 lactation resulted in essentially no treatment or dose related adult F0 parental toxicity at any dose at any time. Reproductive toxicity was not present in F0 males or females. There was also no F1offspring toxicity observed postnatally through the weanling necropsy. Therefore, the F0 male and female systemic no observable adverse effect level (NOAEL) was at or above 1000mg/kg/day for males and females. The NOAELs for F0 reproductive toxicity were observed at or above 1000 mg/kg/day for males and females. The NOAELs for F1 offspring toxicity during lactation were also at or above 1000 mg/kg/day for males and females. (Author)
Executive summary:

In a Guideline (modified OECD 422) GLP study with extended treatment to Day 21 of lactation, TDP administered by gavage once daily at 0, 50, 250, 1000 mg/kg/day to parental FO CD® (SD) rats, 10/sex/group, through prebreed, mating, gestation, and Fl lactation, resulted in essentially no treatment- or dose-related adult FO parental toxicity at any dose at any time. Reproductive toxicity was not present in FO males or females. There was also no Fl offspring toxicity observed postnatally through the weanling necropsy. Therefore, the FO male (28 days) and female (8 -9 weeks) systemic no observable adverse effect levell (NOAEL) was at or above 1000 mg/kg/day. The NOAELs for FO reproductive toxicity were at or above 1000 mg/kg/day for males and females. The NOAELs for Fl offspring toxicity during lactation were also at or above 1000 mg/kg/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
Quality of whole database:
The available data are reliable and suitable to address REACH requirements.
Additional information

Use of data on a closely related analogue, triisodecyl phosphite (TDP), has been selected to represent the fertility effects of TiTDP. Based on similar toxicity on other mammalian endpoints it appears appropriate to use TDP repeat-dose toxicity data to read-across to TiTDP. In addition, the OECD- accepted category approach for the C10 and C13 isoalkyl alcohols, hydrolysis products of TDP and TiTDP, respectively, further supports this read-across approach. See justification document in Section 13.  

 

In a Guideline (modified OECD 422) GLP study with extended treatment to Day 21 of lactation, TDP administered by gavage once daily at 0, 50, 250 and 1000 mg/kg/day to parental F0 CD (SD) rats, 10/sex/group through prebreed, mating, gestation and lactation resulted in essentially no treatment- or dose-related adult F0 parental toxicity at any dose at any time. Reproductive toxicity was not present in F0 males and females. There was also no F1 offspring toxicity observed postnatally through the weanling necropsy. Therefore, the F0 male and female systemic no observable adverse effect level (NOAEL) was at or above 1000 mg/kg/day. The NOAELs for F0 reproductive toxicity during lactation were also at or above 1000 mg/kg/day for males and females.

.

The following information is taken into account for any hazard / risk assessment:

No effects on fertility up to the top dose of 1000 mg/kg.


Short description of key information:
The fertility effects of TiTDP via the oral route has been read-across from the closely related analogue TDP and based on the following study: TDP showed no signs of reproduction/developmental toxicity in an enhanced OECD 422 reproduction/developmental screening toxicity test at doses up to 1000 mg/kg bw/day.

Justification for selection of Effect on fertility via oral route:
The effects on fertility of TiTDP via the oral route has been read-across from a study conducted with the closely related analogue TDP. The study was conducted according to OECD Guideline 422 and to GLP and is adequately reported. Justification for read across to TDP is provided in Section 13.

Effects on developmental toxicity

Description of key information

Prenatal developmental toxicity (OECD 414 limit dose) - no adverse maternal or fetal effects were observed at the limit dose of 1000 mg/kg/day (2021).


Prenatal developmental toxicity (OECD 414) - no adverse maternal or fetal effects were observed at the highest dose tested, 375 mg/kg bw/day (2018).

Link to relevant study records
Reference
Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2021
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Version / remarks:
June 25, 2018
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Limit test:
yes
Specific details on test material used for the study:
NAME OF TEST MATERIAL (as stated in the study report): Trisisotridecylphosphite

SOURCE OF TEST MATERIAL
- Source of test material: Valtris Specialty Chemicals Ltd.
- Batch No. W057094
- Expiration date of the lot/batch: March 15, 2022
- Purity: 98%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature in original container.
- Stability under test conditions: The stability of the test item in dose formulations was determined using a validated analytical method. The test item was found stable up to 24 hours under use conditions (i.e., room temperature). Dose formulations were prepared every day and used within 4 hours of preparation.
Species:
rat
Strain:
Wistar
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Jai Research Foundation Animal Breeding Facility.
- Age at study initiation: At the initiation of the acclimatisation female rats were 11-13 weeks old.
- Weight at study initiation: 199.4 – 232.8 g at beginning of acclimatisation.
- Housing: female rats were housed individually, except during the mating period.
- Diet (e.g. ad libitum): standard rodent pellet diet (Certified Teklad Global 14% Protein Rodent Diet, Batch No 2014SC-090920MA,, procured from Envigo Laboratories, Inc., USA), ad libitum
- Water (e.g. ad libitum): filtered drinking water (filtered through Reverse Osmosis water filtration system) in polypropylene bottles, ad libitum.
- Acclimation period: 6 days prior to mating

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 - 24
- Humidity (%): 65 - 68
- Air changes (per hr): 16
- Photoperiod (hrs dark / hrs light): 12 hours fluorescent light and 12 hours darkness, light hours were approximately 06.00 - 18.00 hours.

IN-LIFE DATES: Acclimatisation start March 05, 2021; Experiment Completion June 23, 2021.
Route of administration:
oral: gavage
Vehicle:
corn oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: Dose formulations were prepared every day prior to the dosing and were used within 4 hours of preparation. Dose formulations were thoroughly mixed using a magnetic stirrer.

VEHICLE
- Justification for use and choice of vehicle (if other than water): solubility

DOSE VOLUME: 4 mL/kg b.w.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
The test item concentration and homogeneity of test item in samples of the control and dose formulations were analysed once prior to initiation of treatment and once during the treatment period. The samples were analysed at JRF using validated analytical method (JRF Study N° 228-2-13-18511).

Two sets of samples (4 samples per set) were collected by sampling three aliquots (upper, middle and lower layers) from each concentration except control (only one aliquot). One set of samples was used for analyses and the other set of samples was stored at refrigerated. On each occasion, the mean concentration was determined and compared with the nominal value and the coefficient of variation calculated. The acceptance criteria was ±15% deviation from nominal value and %CV <10.
Details on mating procedure:
After the acclimatisation period, each female rat was cohabitated with an untreated male rat (1:1) until the requisite numbers of mated female rats (25/group) were obtained. Detection of mating was confirmed by evidence of a copulatory plug in the vagina or by sperm positive vaginal smear. After confirmation of mating, each the female rats were returned to an individual cage, assigned to a group and that day was designated as the day 0 of gestation (GD 0).
Duration of treatment / exposure:
Days 5 - 19 of gestation
Frequency of treatment:
Once daily
Duration of test:
Day 20 of gestation
Dose / conc.:
0 mg/kg bw/day
Dose / conc.:
1 000 mg/kg bw/day
No. of animals per sex per dose:
25 mated females per group
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: The limit dose was chosen based on a testing requirement from ECHA following submission of a multi dose level OECD 414 guideline GLP study (JRF, 2018), which reported a NOAEL at the highest level tested (375 mg/kg/day).
Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily, for mortality and morbidity

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: During the study period, visible clinical signs, such as changes in the skin, fur, eye, mucous membranes, as well as the behavioural pattern of the mated female rats, were recorded twice daily.

BODY WEIGHT: Yes
- Time schedule: on gestation days 0, 3, 5, 8, 11, 14, 17, and 20.

FOOD CONSUMPTION: Yes
- Time schedule: for the periods 0–3, 3–5, 5–8, 8–11, 11–14, 14–17, 17–20, and 5-20 days of gestation.

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- All female rats were weighed, euthanised by carbon dioxide asphyxiation, dissected and examined macroscopically.

ORGAN WEIGHTS AND HISTOPATHOLOGY: Yes
- At the time of terminal sacrifice, the weight of the liver, kidney, brain, and thyroid gland was taken
after collection from all female rat and preserved in 10% neutral buffered formalin for histopathology.
Organ weights relative to terminal body weight and brain weight were calculated. Detailed histological examination of liver, kidney, and thyroid gland was performed in high and control dose groups. Brain was collected and preserved but histopathology was not performed.
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Number of live fetuses: Yes
- Number of dead fetuses: Yes

Non-gravid uteri were further examined by immersing in 5% ammonium sulphide solution for confirming the non-pregnant status.
Blood sampling:
At the time of terminal sacrifice on GD 20, blood (approximately 3 mL) was collected from all-female
rats under anaesthesia (isoflurane) by orbital plexus puncture.

Serum thyroid hormones (T4, TSH, and T3) were analysed from all female rats at the terminal sacrifice.

Serum samples were also analysed for UDP Glucuronosyltransferase (UDPG) and clinical chemistry
parameters (alanine aminotransferase, aspartate aminotransferase, creatinine, total protein, albumin,
and urea) of liver and kidney.
Fetal examinations:
- External examinations: Yes: [all per litter]
- Soft tissue examinations: Yes: [approximately half per litter]
- Skeletal examinations: Yes: [remaining half per litter]
- Head examinations: Yes: [approximately half per litter]
- Fetus sex (based on anogenital distance): Yes [all per litter]
- Fetuses body weight: Yes [all male fetuses per litter, all female fetuses per litter]
Statistics:
TYPE OF DATA:
Parametric: Body weight, body weight change, food consumption, corrected body weight,
absolute and relative uterine weight, organ weight, organ weight ratio, male sex ratio,
pre-and postnatal loss (%), live foetus (%), and resorption (%), ano-genital distance
Non-parametric: Mortality rate, pregnancy rate, foetal observation, litter size, number of corpora lutea, number of implants, number of a live foetus, number of pre-and postnatal losses,
number of resorptions

SIGNIFICANCE LEVEL:
Parametric: 5% and 1% level between control and treated group
Non-parametric: 5% level between control and treated group
Indices:
Pre-implantation loss (%)
Post-implantation loss (%)
Live fetuses (%)
Dead fetuses (%)
Male Sex ratio
Resorptions (%)
Historical control data:
No
Clinical signs:
no effects observed
Description (incidence and severity):
No clinical signs of toxicity were observed during the experimental period in any dose group.
Mortality:
no mortality observed
Description (incidence):
No mortality or morbidity was observed in any dose group.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
The mean body weight and Day 20 corrected body weight of the pregnant female rats were comparable between the control and the test item treated group.


Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
The mean food consumption of the pregnant female rats was comparable between the control, and the test item treated group.
Food efficiency:
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
Statistically, a significant increase in the serum ALT level was observed in the 1000 mg/kg b. wt./day
dose group. This alteration is considered an effect of the test item treatment but non-adverse in
nature in the absence of histopathological alterations in the liver.

Statistically, a significant increase in the serum UDP Glucuronosyltransferase (UDPG) level was
observed in the 1000 mg/kg b. wt./day dose group. This alteration reveals enzyme induction activity
of the test item and considered as an effect of the test item treatment but non-adverse in nature in the
absence of the histopathological alteration in the liver.
Endocrine findings:
effects observed, non-treatment-related
Description (incidence and severity):
Serum TSH and T4 levels were comparable with that of the control group.

Statistically, a significant decrease in serum T3 level was observed in pregnant female rats belonging
to 1000 mg/kg b. wt./day dose group. This finding could be related to the induction of UDP
Glucuronosyltransferase (UDPG) seen in the liver, and associated increased clearance of the thyroid
hormones. In the absence of corresponding changes in TSH, and in the absence of histopathological alterations in thyroid, this finding is considered to be non-adverse.
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):
The mean absolute and relative uterine weight of the pregnant female rats were comparable between the control and the test item treated group.

Statistically, a significant increase in the absolute (around 13% increase vs control) and relative
liver weights (vs terminal body weight and brain weight) were noted in the 1000 mg/kg b. wt./day
dose group. Similarly, statistically, a significant increase in the absolute (around 15% increase vs
control) and relative (vs brain weight) thyroid gland weights were observed in the 1000 mg/kg b. wt./day dose group. These effects were considered to be related to treatment but were considered nonadverse in nature in the absence of the treatment-related histopathological alterations in these organs.
Gross pathological findings:
no effects observed
Description (incidence and severity):
External and internal (gross) examination of the terminally sacrificed female rats did not reveal any lesion of pathological significance.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
effects observed, non-treatment-related
Description (incidence and severity):
Histological examination of liver, kidney, and thyroid gland did not reveal any treatment-related lesion
in rats of the control as well as the high dose group. The lesions observed, ectopic thymus and kidney pelvis dilation, were considered to be congenital/spontaneous as the lesions were present in both the treated and control group rats.
Other effects:
no effects observed
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
Details on maternal toxic effects:
The mean numbers of corpora lutea, implantation sites, live foetuses, dead foetuses, resorptions (early, late, and total), pre-implantation loss, and post-implantation loss, the mean percent of live foetuses, dead foetuses, pre-implantation loss, post-implantation loss, and total resorptions were comparable between the control, and test item treated group.
Dose descriptor:
NOEL
Remarks:
Maternal Developmental Toxicity
Effect level:
>= 1 000 mg/kg bw/day
Based on:
test mat.
Remarks on result:
other: No treatment related effect observed at the limit dose of 1000 mg/kg/day.
Dose descriptor:
NOAEL
Remarks:
Maternal Systemic Toxicity
Effect level:
>= 1 000 mg/kg bw/day
Based on:
test mat.
Remarks on result:
other: No adverse effects were observed at the limit dose of 1000 mg/kg/day.
Abnormalities:
no effects observed
Description (incidence and severity):
No adverse effects were observed at the limit dose of 1000 mg/kg/day.
Fetal body weight changes:
no effects observed
Description (incidence and severity):
The mean body weight of male, female and total fetuses (male + female) was comparable between the control and the test item treated groups.
Reduction in number of live offspring:
no effects observed
Description (incidence and severity):
The mean number of corpora lutea, implantation sites, live foetuses, dead foetuses, resorptions (early, late, and total), pre-implantation loss, and post-implantation loss, as well as the mean percent of live foetuses, dead foetuses, pre-implantation loss, post-implantation loss, and total resorptions were comparable between the control, and test item treated group.
Changes in sex ratio:
no effects observed
Description (incidence and severity):
The male sex ratio was comparable between the control and the test item treated group.
Changes in litter size and weights:
no effects observed
Description (incidence and severity):
The mean count of male, female and total foetuses (male + female) was comparable between the
control group, and the test item treated group.
Anogenital distance of all rodent fetuses:
no effects observed
Description (incidence and severity):
The mean anogenital distance of male and female foetuses was comparable
between the control and the test item treated group.
Changes in postnatal survival:
not examined
External malformations:
no effects observed
Description (incidence and severity):
No treatment-related external anomalies were observed.
Skeletal malformations:
no effects observed
Description (incidence and severity):
No treatment-related increases in the incidence of skeletal malformations were observed. Findings were similar in the treated and control group, and at incidences within the range of historical control data.
Visceral malformations:
no effects observed
Description (incidence and severity):
No treatment-related visceral anomalies were observed. Spontaneous findings in the treated and control group were within the historical control data range.

No treatment-related anomalies were observed in the head razor sections.
Other effects:
no effects observed
Details on embryotoxic / teratogenic effects:
No effects were observed in this study.
Dose descriptor:
NOEL
Effect level:
>= 1 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Remarks on result:
other: No effects were observed at the limit dose of 1000 mg/kg/day.
Abnormalities:
no effects observed
Description (incidence and severity):
No effects were observed at the limit dose of 1000 mg/kg/day.
Developmental effects observed:
no

The following tabluar results and Appendices are provided in two separate attachments:


Table 2: Pregnancy Data Summary


Table 3: Clinical Observations Summary (Maternal)


Table 4: Body Weight Summary (Maternal)


Table 5: Body Weight Gain Summary (Maternal)


Table 6: Food Consumption Summary


Table 7: Prenatal Data Summary


Table 8: Foetal Data Summary


Table 9: Foetal Gross External Observation Summary


Table 10: Foetal Visceral Observations Summary


Table 11: Foetal Head Razor Section Observation Summary


Table 12: Foetal Skeletal Observation Summary


Appendix 11: Pathology Report


Appendix 12: Thyroid Hormone Analysis Report (TSH)


Appendix 13: Thyroid Hormone Analysis Report (T3 and T4)


Appendix 14: UDPG Analysis Report

Conclusions:
In this OECD 414 guideline GLP limit study of trisisotridecyl phosphite, no adverse maternal systemic effects were observed at the limit dose of 1000 mg/kg bw/day, and no treatment-related effects were observed on maternal reproduction or fetal development. Therefore, the NOAEL for maternal systemic toxicity is considered to be 1000 mg/kg bw/day. This dose in considered to be a NOEL for maternal and fetal developmental toxicity.
Executive summary:

An enhanced OECD 414 guideline GLP limit study was conducted on tris isotridecyl phosphite. Groups of 25 female Wistar rats were treated by oral gavage on gestation days (GD) 5 to 19, by at  dose levels of 0 (corn oil vehicle), or 1000 mg/kg b. wt./day. Rats were observed twice daily for mortality and clinical signs. Maternal body weights and food consumption were recorded throughout the gestation period.


All rats were sacrificed on GD 20 and assessed for gross pathological changes. The uteri were excised, weighed, and examined for the numbers of implantation sites, early and late resorptions, and numbers of live and dead foetuses. The ovaries were excised, and the number of corpora lutea counted. The foetuses were identified for sex, weighed, and examined for external findings. The anogenital distance was measured for all foetuses. At the time of terminal sacrifice, the weight of the thyroid gland, liver, kidney, and brain was recorded from all-female rats and preserved for histopathology. Detailed histological examination of the liver, kidney, and thyroid gland was performed in control and high dose group female rats. Serum thyroid hormones T3 (liothyronine), T4 (levothyroxine), and TSH (thyroid-stimulating hormone) were analysed from all pregnant female rats during the terminal sacrifice. UDP Glucuronosyltransferase (UDPG) and clinical chemistry parameters (alanine aminotransferase, aspartate aminotransferase, creatinine, total protein, albumin, and urea) of liver and kidney were also analysed from all pregnant female rats.  The maternal liver evaluations were included to aid interpretation of thyroid findings. Following appropriate fixation, foetuses were examined for visceral abnormalities, including razor sectioning of the head and skeletal abnormalities.


No treatment-related effects were seen on maternal reproduction parameters, or on fetal development.


Treatment-related effects were limited to liver and thyroid findings in maternal animals.  Nonadverse effects seen in the 1000 mg/kg b. wt./day dose group animals included:


- Statistically significant increase in the serum ALT level vs controls.


- Statistically significant increase in the serum UDP Glucuronosyltransferase (UDPG) vs controls. This finding indicates enzyme induction activity in the liver and and has been  associated with increased clearance of the thyroid hormones.


 - Statistically significant decrease in serum T3 level vs controls. This finding could be related to the induction of UDP Glucuronosyltransferase (UDPG) seen in the liver.

- Statistically significant increase in the absolute and relative liver and thyroid weights vs controls.


Because no treatment-related histopathological alterations were seen in the liver or thyroid, these findings were considered to be non-adverse in nature.





Based on these results, the NOAEL for maternal systemic toxicity is considered to be 1000 mg/kg bw/day. This dose in considered to be a NOEL for maternal reproduction and fetal developmental toxicity.




Effect on developmental toxicity: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
The available data are reliable and suitable to address REACH requirements.
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

In two OECD 414 guideline GLP studies of TiTDP, no maternal or fetal effects were observed at the highest doses tested, 375 mg/kg bw/day in a 2018 study and the limit dose of 1000 mg/kg/day in a follow-up 2021 study.  Furthermore, The developmental toxicity of TiTDP via the oral route has been read-across from the closely related analogue TDP (see discussion under fertility). Based on the available data, TiTDP is not considered to be a developmental toxicant.


The following information is taken into account for any hazard / risk assessment:


No adverse maternal or fetal effects were seen in two prenatal developmental toxicity studies (OECD 414) of TiTDP at the highest doses tested, 375 mg/kg bw/day in a 2018 study, and the limit dose of 1000 mg/kg/day in a follow-up 2021 study.


 


No effects were seen in a reproductive/development screening toxicity study (OECD 422) with the top dose of 1000 mg/kg (read across from TDP). Justification for read across to TDP is provided in Section 13.



Justification for selection of Effect on developmental toxicity: via oral route:
Based on the availble data, including no effects seen in two prenatal developmental toxicity studies, TiTDP is not considered to be a developmental toxicant.

Justification for classification or non-classification

The available data concerning reproduction and developmental toxicity of TiTDP are reliable and suitable for classification purposes under Regulation 1272/2008.


No adverse maternal or fetal effects were seen in two prenatal developmental toxicity studies (OECD 414) of TiTDP at the highest dose tested, 375 mg/kg bw/day in a 2018 study, and the limit dose of 1000 mg/kg/day in a follow-up 2021 study.  All mutagenicity studies of TiTDP are likewise negative.


In addition, the reproductive toxicity of TiTDP via the oral route has been read-across from the closely related analogue TDP. Under the test conditions of an enhanced OECD TG 422 study, TDP administered to male and female rats up to a dose level of 1000 mg/kg bw/day for a period of up to 8 weeks was not toxic to reproduction and had no effect on fertility or development.


Based on these results, TiTDP does not warrant classification according to the criteria described in Regulation (EC) No 1272/2008.

Additional information