4-methoxybenzyl alcohol

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

The NOAEL of the structural analogue substance p-methoxybenzyl alcohol for reproductive toxicity was considered to be 400 mg/kg bw/day for males and females. The NOAEL for developmental toxicity was considered to be 100 mg/kg bw/day for pups.

Link to relevant study records

Reference

Reference 1

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

Please refer to attached "Read-across justification" in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Dose descriptor:

NOAEL

Remarks:

general toxicity/reproductive toxicity

Effect level:

400 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No test item related effects were observed.

Key result

Critical effects observed:

no

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

viability

mortality

body weight and weight gain

Key result

Reproductive effects observed:

yes

Lowest effective dose / conc.:

400 mg/kg bw/day (nominal)

Treatment related:

yes

Relation to other toxic effects:

reproductive effects in the absence of other toxic effects

Dose response relationship:

yes

Reference 2

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016-10-11 to 2017-04-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Version / remarks:

July 29, 2016

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Remarks:

Crl:CD(SD), SPF

Details on species / strain selection:

Sprague-Dawley rats are commonly used in both the general systemic toxicity and reproductive and developmental toxicity studies with a large historical control database. In addition, the rat is a required species in the regulatory guidelines.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Females nulliparous and non-pregnant: yes (not stated directly but females were determined to have normal estrous cycle)
- Age at study initiation: male: 10 weeks; female: 12 weeks
- Weight at study initiation: male: 353.2–402.3 g; female: 228.0–284.1 g
- Fasting period before study: no
- Housing: Animals per cage: 1 (during the quarantine-acclimation period), 1 (during the dosing period), 1 male and 1 female (during the mating period), 1 female and neonates (during the lactation period); Stainless wire mesh cages, 260W×350D×210H (mm) and Polycarbonate cage 260W×420D×180H (mm)
- Diet: ad libitum, Pelleted rodent chow (Teklad Certified Irradiated Global 18 % Protein Rodent Diet 2918C)
- Water: ad libitum, tap water
- Acclimation period: 7 days

DETAILS OF FOOD AND WATER QUALITY:
The certificate of feed analysis was provided by the supplier and the results of feed analysis met the allowable standard of the test facility.
Public tap water was filtered and irradiated by ultraviolet light. Samples of drinking water are analyzed for specified microorganisms once a month and all environmental contaminants once a year according to the Regulation of Quality Criteria for Potable Water and Test. The results of water analysis met the allowable standard of the test facility.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.7–24.9
- Humidity (%): 43.9–63.6
- Air changes (per hr): 10 – 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The required amount of the test substance was weighed using electronic balances (CP323S, CP423S, BP3100S, ENTRIS423i-1S, Sartorius, Germany) and placed in a container. The test substance was mixed with a small amount of vehicle to dissolve using a magnetic stirrer, and then the vehicle was gradually added to yield the desired concentrations. The dosing formulations were stored in a refrigerator (5.0–6.0 °C). These dosing formulations were used within 7 days.

VEHICLE
- Justification for use and choice of vehicle: Through the preliminary solubility test to determine the solubility and dispersion characteristics of the test substance, corn oil was selected as the vehicle because the test substance was well dissolved in it.
- Concentration in vehicle: 0.1 and 200 mg/mL
- Amount of vehicle: 5 mL/kg
- Lot/batch no. (if required): MKBW9504V (Sigma-Aldrich)

Details on mating procedure:

- M/F ratio per cage: 1/1
- Length of cohabitation: 2 weeks
- Proof of pregnancy: vaginal plug or sperm in vaginal smear referred to as day 0 of gestation
- Further matings after two unsuccessful attempts: no
- After successful mating each pregnant female was caged: single
- Any other deviations from standard protocol: no

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analyses of the dosing formulations were conducted using a gas chromatography (GC-2010 series, Shimadzu Corp., Japan). Samples were taken three times from the middle of each dosing formulation prior to dosing and analyzed for verification of dose level concentration. The results of dose concentration analyses were determined to be in the range of 97.43–103.20 %. These results were within the acceptable limits (± 15 % of nominal values).

Duration of treatment / exposure:

Males of the main group were dosed for a total of 50 days (prior to mating for 2 weeks, during 2 weeks of mating and 22 days of post-mating).
Males and females of the recovery groups were dosed for 50 days.
Females of the main group were dosed for 2 weeks prior to mating until Postpartum Day 13. Females showing no evidence of parturition signs were dosed until Gestation Day 25.

Frequency of treatment:

once daily

Details on study schedule:

- F1 parental animals were not mated.

Dose / conc.:

25 mg/kg bw/day (nominal)

Dose / conc.:

100 mg/kg bw/day (nominal)

Dose / conc.:

400 mg/kg bw/day (nominal)

No. of animals per sex per dose:

Main groups: 12
Recovery groups: 6

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: In previously conducted 2-week repeated oral dose range finding study salivation was observed in both sexes at 800 mg/kg bw/day. An increase of the relative kidney weight was noted in males at 800 mg/kg bw/day. Therefore, the high dose level was selected at 400 mg/kg bw/day. Then, the mid and low dose levels were selected at 100 and 25 mg/kg bw/day, respectively.
- Post-exposure recovery period in satellite groups: 2 weeks

Positive control:

No positive control was conducted.

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations included: general condition, clinical signs, moribundity, mortality and females also signs of abortion and premature birth

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: prior to dosing, once weekly for the dosing and recovery periods
- Detailed clinical observations included: skin, fur, eyes, mucous membranes, occurrence of secretion and excretion, autonomic activity (lacrimation, piloerection, pupil size, unusual respiratory pattern etc.), changes in gait, posture and response to handling, and the presence of clonic or tonic movements, stereotypy (excessive grooming, repetitive circling, etc.) or bizarre behavior (self-mutilation, walking backward, etc.)

BODY WEIGHT: Yes
- Time schedule for examinations: males of main group and males/females of recovery group: just prior to dosing on Day 1 (the first day of dosing), once a week throughout the dosing period and recovery period, the day prior to necropsy and on the day of necropsy (fasted body weights); females of main group: just prior to dosing on Day 1 (the first day of dosing), once a week throughout the dosing period, on Gestation Days 0, 7, 14 and 20, on Postpartum Days 0, 4 and 13, the day prior to necropsy and on the day of necropsy.

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No
Individual food consumption was calculated by subtracting the amount of residual feed from the amount presented.

FOOD EFFICIENCY: No

OTHERS:
OPHTHALMOSCOPIC EXAMINATION: Yes, as part of the detailed neurological examination

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at necropsy
- Anaesthetic used for blood collection: Yes, isoflurane
- Animals fasted: Yes, 18 h
- How many animals: 6 females and males from the main groups, animals from the recovery groups
- Parameters checked in table No.1 were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at necropsy
- Animals fasted: Yes, 18 h
- How many animals: 6 females and males from the main groups, animals from the recovery groups
- Parameters checked in table No.2 were examined.

URINALYSIS: Yes
- Time schedule for collection of urine: two days before necropsy
- Metabolism cages used for collection of urine: Not specified
- Animals fasted: Yes, but free access to drinking water
- Parameters checked in table No.3 were examined.

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: few days before necropsy
- Dose groups that were examined: 6 males and 6 females were randomly selected from the main groups in addition to all recovery animals
- Battery of functions tested: pinna reflex, auditory reflex, corneal reflex, pupillary reflex, grip strength test, motor activity

IIMMUNOLOGY: Yes
- Time schedule for examinations: at termination
- How many animals: all adult males and dams of the main group
- Dose groups that were examined: all
- Parameters examined: Total Thyroxine (T4) [ug/dL] Method: Chemiluminescent competitive immunoassay

Oestrous cyclicity (parental animals):

The estrous cycle for females of the main groups was observed from dosing initiation day to confirmed copulation day and on the necropsy day. Smears of vaginal mucosa were prepared in the morning daily. Prepared smears of the vaginal mucosa were stained with Diff Quick stain (Hemacolor® for microscopy, Merck, Germany). Stained vaginal mucosa smears were examined using light microscopy. The estrous cycle is divided into four stages; proestrus, estrus, metestrus and diestrus. One estrous cycle was defined as the period between the day of estrus and the day prior to next estrus.
Estrous cycle was calculated from dosing initiation day to the day before mating initiation.

Sperm parameters (parental animals):

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

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes
- If yes, maximum of 8 pups/litter (4/sex/litter as nearly as possible); excess pups were killed and discarded.

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical abnormalities, anogenital distance (AGD), presence of nipples/areolae in male pups

GROSS EXAMINATION OF DEAD PUPS:
no, possible cause of death was not determined for pups born or found dead

ASSESSMENT OF DEVELOPMENTAL NEUROTOXICITY: No observations conducted.

ASSESSMENT OF DEVELOPMENTAL IMMUNOTOXICITY:
ENDOCRINE FUNCTION: Yes
- Time schedule for examinations: pups: on PND 4 and 13
- How many animals: at least two pups per litter (if available above culling target)
- Dose groups that were examined: all
- Parameters examined: Total Thyroxine (T4) [ug/dL] Method: Chemiluminescent competitive immunoassay

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals of the main groups were sacrificed on Day 51. All animals of the recovery groups were sacrificed two weeks after final dosing.
- Maternal animals: All surviving animals of the main groups were sacrificed on Postpartum Day 14. Non-copulated females were sacrificed on Day 26 after the last day of mating. Non-pregnant females were sacrificed on Gestation Day 26. All animals of the recovery groups were sacrificed two weeks after final dosing.

Animals that died during the study period:
Necropsies were conducted on all animals found dead as soon as possible. When not feasible, they were stored under refrigeration until necropsy. Gross pathology findings were recorded and tissue samples were collected for histopathology.

GROSS PATHOLOGY: Yes. All surviving animals were sacrificed by exsanguination from the abdominal aorta under isoflurane anesthesia. Complete gross postmortem examinations were conducted on all animals including the external surfaces and internal organs.

Organ weights:
The testis and epididymis of all adult males were weighed.
Six males and six females were randomly selected from the main group animals in addition to all recovery animals for necropsy. The organ weights from organs listed in Table No. 4 were determined.

HISTOPATHOLOGY: Yes. The testis, epididymis and eyes with optic nerves were fixed in Davidson’s fixative. All other tissues were preserved in 10 % neutral buffered formalin. The thyroid from one male and one female pups per litter were preserved in 10% neutral buffered formalin on PND 13. Organs listed in Table No. 5 were prepared for histopathology. Examinations were conducted in six males and six females from the control, low, mid and high groups, for all gross, macroscopic lesions in all animals and in addition all tissues from animals found dead or killed in a moribund condition during the study.

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring were sacrificed at PND 4 or 13.

GROSS NECROPSY
- Gross necropsy consisted of external examinations.

HISTOPATHOLOGY / ORGAN WEIGTHS
The thyroid from one male and one female pups per litter were preserved in 10 % neutral buffered formalin on PND 13.

Statistics:

The statistical analysis of this study was conducted using the SAS program (SAS® 9.3, SAS Institute Inc., U.S.A.).
For the data including body weights, food consumption, estrous cycle, mating period, gestation period, post-implantation loss, body weights and birth and survival rates of pups, AGD index, nipple number, thyroid hormone value, urine volume, hematology and clinical chemistry parameters, organ weights, sensory reactivity and motor activity, the Bartlett test was conducted to test for homogeneity of variance (significance level: 0.05). One-way analysis of variance (ANOVA) test was employed on homogeneous data, then if significant (significance level: 0.05), followed by Dunnett’s test for multiple comparisons (significance levels: 0.05 and 0.01, two-tailed). Kruskal-Wallis test was employed on heterogeneous data, then if significant (significance level: 0.05), Steel’s test was performed for multiple comparisons (significance levels: 0.05 and 0.01, two-tailed).
The data of mating index, fertility index and other data associated with gestation were analyzed utilizing Fisher’s exact test (significance levels: 0.05 and 0.01).
For the data of recovery groups, Folded-F test was employed to test homogeneity of variance (significance level: 0.05, two-tailed). Student t-test was employed for homogeneity, but if overruled, Aspin-Welch t-test was applied (significance levels: 0.05 and 0.01, two-tailed).

Reproductive indices:

Mating index, mating period, gestation period, male and female fertility index and gestation index were calculated.

Offspring viability indices:

Mean litter size, live birth index, viability index on postnatal day 0 and 4, sex ratio were calculated.

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

In the main groups, hematuria was observed in one male at 0 mg/kg bw/day from Day 23 to the end of dosing. This symptom was considered to be incidental. Mass in the chest was observed in three females at 100 mg/kg bw/day from GD 9 to the end of dosing. The mass in the chest was a mammary gland tumor, however, this lesion was not considered to be related to the test substance since there was no dose-dependency and it could occur spontaneously. Soiled perineal region was temporarily observed in one female at 25 mg/kg bw/day. This symptom was considered to be incidental because of a lack of dose dependency. Salivation was observed in two males at 400 mg/kg bw/day from Day 25. Salivation was also observed in four females at 400 mg/kg bw/day from GD 3 to PPD 7. However, salivation was considered to have little toxicological significance since it was caused by physicochemical characteristics.

No clinical signs were observed in males and females of the main and recovery groups in the detailed examinations once a week.

Dermal irritation (if dermal study):

not examined

Mortality:

mortality observed, non-treatment-related

Description (incidence):

All males of the main group and all animals of recovery groups survived the duration of the study.
In the main groups, one dam at 0 mg/kg bw/day died during parturition on GD 25. Normal gestation period of rats is 21–23 days. The dam showed prolonged pregnancy and dystocia on GD 25. It was judged that cause of death was prolonged gestation period and big size of fetus on GD 25.
One dam at 100 mg/kg bw/day died on PPD 5. This dam was in poor condition such as soiled perineal region, staining around mouth and lacrimation. Pups of this dam had no milk in the stomach. However, the death was considered to be incidental because there was a lack of dose dependency.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No significant differences in body weight changes were noted in males and females of the main and recovery groups compared to the control group.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

In the main groups, statistically significant increases in food consumption were noted in males at 400 mg/kg bw/day from Day 8 to the end of dosing. Statistically significant increases in food consumption were noted in females at 25 and 400 mg/kg bw/day on Day 14. Statistically significant decreases in females at 400 mg/kg bw/day were noted on PPDs 4 and 13.
In the recovery groups, statistically significant increases in food consumption were noted in males and females at 400 mg/kg bw/day.
However, these statistical significances in food consumption had little toxicological meanings since they were not related to body weight changes.

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

no effects observed

Description (incidence and severity):

No test substance-related effects on pupillary reflex and corneal reflex were observed in animals of both sexes in the main and recovery groups when compared to the control group.

Haematological findings:

no effects observed

Description (incidence and severity):

No test substance-related adverse effects were observed in any animal in the main and recovery groups.
Other statistical significances were considered not to be test substance-related changes because of small magnitude and the values were within the range of historical reference data.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

No test substance-related adverse effects were observed in any animal in the main and recovery groups.
Other statistical significances were considered not to be test substance-related changes because of small magnitude and the values were within the range of historical reference data.

Urinalysis findings:

effects observed, non-treatment-related

Description (incidence and severity):

In the main groups, occult blood and erythrocyte were noted in the urine of one male at 25 mg/kg bw/day. However, it was considered to be incidental and not to be a test substance-related effect because there was no dose dependency.
In the recovery groups, no test substance-related effect was noted in males at 400 mg/kg bw/day.

Behaviour (functional findings):

effects observed, non-treatment-related

Description (incidence and severity):

No test substance-related effects on auditory reflex and pinna reflex were observed in animals of both sexes in the main and recovery groups when compared to the control group.
In the main groups, there was no test substance-related effect on the grip strength in both sexes when compared to the control group. In spontaneous motor activity, a statistically significant decrease in 20–30 min vertical count was noted in males at 400 mg/kg bw/day. However, this statistical significance had little toxicological significance because it was a transient and temporary change.
In the recovery groups, there were no test substance-related effects on the grip strength and spontaneous motor activity when compared to the control group.

Immunological findings:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Dead animals
In one dead dam at 100 mg/kg bw/day, mineralization at slight/moderate severity in multiple organs (heart, kidney and stomach) was observed along with chief cell hyperplasia at slight severity in the parathyroid and fibrous osteodystrophy at slight/moderate severity in the femur and sternum. The mineralization was observed in vascular wall or perivascular tissues in the heart and stomach. The deposit of minerals in the kidney was mainly observed in the lumens of renal tubules with tubular necrosis. The series of these findings were generally associated with hypercalcemia and hyperparathyroidism, and they were deemed to be the cause of death. However, the findings were considered to be not related to the test substance since they were observed in a single case at 100 mg/kg bw/day and post-partum hypercalcemia could occur rarely. The enlarged adrenal gland was in concordance with adrenocortical hypertrophy. Small spleen, of which cause was atrophy, was also observed in the thymus. These findings were considered to be stress-related and secondary to exacerbated condition.
In one dead dam of the control group, the discoloration of the liver corresponded to microscopically observed bridging centrilobular necrosis at moderate severity. The enlarged adrenal gland was correlated with adrenocortical necrosis at severe severity. Also, necrosis/inflammatory cell infiltration at moderate severity in the heart and multifocal pulmonary thrombus at moderate severity in the lung were observed. The cause of death of this dam was deemed to be multiple organ failure due to dystocia accompanied by shock, which was associated with prolonged pregnancy.

Surviving animals
Microscopic examination did not reveal treatment-related changes in either main or recovery groups.
All other microscopic findings seen in various organs and tissues were considered to be spontaneous or incidental, and to be unrelated to the test substance.

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Reproductive function: oestrous cycle:

no effects observed

Description (incidence and severity):

The estrous cycle lengths (day) of females in the 0 (control), 25, 100 and 400 mg/kg bw/day dosing groups were 4.2, 4.1, 4.1 and 4.3 days, respectively. There was no statistically significant difference in any dosing group.
The estrous cycle of females including non-pregnant females on the day of necropsy was all diestrus except one non-pregnant female at 0 mg/kg bw/day.

Reproductive function: sperm measures:

no effects observed

Description (incidence and severity):

No test substance-related adverse effects were observed in any animal in the main and recovery groups.

Reproductive performance:

no effects observed

Description (incidence and severity):

Mating and Gestation:
In the control and 25, 100 and 400 mg/kg bw/day dose groups, the mating periods were 2.3, 1.9, 2.0 and 2.3 days, the mating index was 100.0 %, the gestation periods were 22.3, 22.1, 22.2 and 22.1 days, and the fertility indices of animals of both sexes were 91.7, 100.0, 100.0 and 83.3 %, respectively. There was no statistically significant difference in any dosing group.

Delivery:
In the control and 25, 100 and 400 mg/kg bw/day dose groups, the gestation indices were 90.9, 100.0, 100.0 and 100.0 %, the post-implantation loss rates were 7.7, 6.3, 10.3 and 15.1 %, the live birth indices were 92.3, 93.7, 89.7 and 85.0 %, the mean litter sizes were 15.0, 14.7, 14.9 and 14.2, the viability indices on PND 0 were 99.3, 98.4, 97.0 and 93.7 %.
In addition, prolonged pregnancy and dystocia were observed in one female at 0 mg/kg bw/day. On other hand, normal delivery was noted in the test substance dosing groups.

Key result

Dose descriptor:

NOAEL

Remarks:

general toxicity/reproductive toxicity

Effect level:

400 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No test substance related effects were observed.

Key result

Critical effects observed:

no

Clinical signs:

not examined

Dermal irritation (if dermal study):

not examined

Mortality:

not examined

Body weight and weight changes:

not examined

Food consumption and compound intake (if feeding study):

not examined

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:

not examined

Gross pathological findings:

not examined

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

not examined

Reproductive performance:

not examined

Clinical signs:

not specified

Dermal irritation (if dermal study):

not examined

Mortality / viability:

mortality observed, treatment-related

Description (incidence and severity):

In the control and 25, 100 and 400 mg/kg bw/day dose groups the viability indices on PND 0 were 99.3, 98.4, 97.0 and 93.7 %, and the viability indices on PND 4 were 95.8, 96.0, 88.9 and 66.7 %, respectively.
The viability index of PND 4 was prominently decreased at 400 mg/kg bw/day even though there was no statistical significance. This was considered to be a test substance-related effect.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

On PND 13, body weights in male pups and female pups were decreased at 400 mg/kg bw/day. This was considered to be a test substance-related effect.

Food consumption and compound intake (if feeding study):

not examined

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

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no test substance-related changes in external findings in pups at 25, 100 and 400 mg/kg bw/day.

Histopathological findings:

not examined

Other effects:

no effects observed

Description (incidence and severity):

The sex ratios on PND 0 were 1.1, 1.0, 0.9 and 1.0 at 0, 25, 100 and 400 mg/kg bw/day, respectively.
There were no test substance-related changes in AGD index of male pups and female pups at 25, 100 and 400 mg/kg bw/day on PND 4.
The nipple number was 0 in male pups at 0, 25, 100 and 400 mg/kg bw/day on PND 12. There was no nipple retention in male pups at 0, 25, 100 and 400 mg/kg bw/day on PND 12.

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

no effects observed

Description (incidence and severity):

There were no test substance-related adverse effects in total thyroxine (T4) level in F1 pups of PND 13 at 25, 100 and 400 mg/kg bw/day.

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

viability

mortality

body weight and weight gain

Clinical signs:

not examined

Dermal irritation (if dermal study):

not examined

Mortality / viability:

not examined

Body weight and weight changes:

not examined

Food consumption and compound intake (if feeding study):

not examined

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

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not examined

Histopathological findings:

not examined

Other effects:

not examined

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

not examined

Key result

Reproductive effects observed:

yes

Lowest effective dose / conc.:

400 mg/kg bw/day (nominal)

Treatment related:

yes

Relation to other toxic effects:

reproductive effects in the absence of other toxic effects

Dose response relationship:

yes

Relevant for humans:

not specified

Conclusions:

The NOAEL for reproductive toxicity was considered to be 400 mg/kg bw/day for males and females. The NOAEL for developmental toxicity was considered to be 100 mg/kg bw/day for pups.

Executive summary:

An oral repeated dose toxicity study was conducted according to OECD 422 in rats. The test substance was administered via gavage to groups of 12 male and 12 female rats at concentrations of 0 (control), 25, 100 and 400 mg/kg bw/day. Males of the main group were dosed once daily for a total of 50 days (prior to mating for 2 weeks, during 2 weeks of mating and 22 days of post-mating), and females of the main group were dosed once daily for two weeks prior to mating, throughout gestation and for 13 days after delivery. Also, males and females of the recovery groups (6 animals per sex per group) were dosed for 50 days. All males of the main groups and all animals of the recovery groups survived the duration of the study. One dam at 0 mg/kg bw/day and one dam at 100 mg/kg bw/day were found dead in the main group. Salivation was observed in four females in the main group at 400 mg/kg bw/day and one male in the recovery group at 400 mg/kg bw/day during the dosing period, but it was not considered to have toxicological significance. The mass in the chest was a mammary gland tumor, however, this lesion was not considered to be related to the test substance since there was no dose-dependency and it could occur spontaneously. No test substance-related adverse effects were noted in the results of body weights, food consumption, estrous cycle, sensory function, motor activity, urinalysis, hematology, clinical chemistry, organ weights and thyroid hormone analysis in adult animals of the test substance-dosed groups. In one dead dam at 100 mg/kg bw/day, mineralization at slight/moderate severity in multiple organs was observed along with chief cell hyperplasia at slight severity in the parathyroid and fibrous osteodystrophy at slight/moderate severity in the femur and sternum. These findings were associated with hypercalcemia and hyperparathyroidism. However, the findings were considered to be not related to the test substance since they were observed in a single case at 100 mg/kg bw/day and post-partum hypercalcemia occurred rarely. In one dead dam of the control group, multiple organ failure was observed and it was due to dystocia accompanied by shock, which was associated with prolonged pregnancy. The viability index of Postnatal Day (PND) 4 was markedly decreased at 400 mg/kg bw/day. On PND 13, body weights of male pups and female pups were decreased at 400 mg/kg bw/day. No test substance-related adverse effects were noted in the results of the estrous cycle, mating period, mating index, gestation period, male and female fertility indexes, gestation index, post-implantation loss rate, live birth index, mean litter size, external examination of pups, sex ratio of pups and viability index of PND 0. No test substance-related effects were noted in the results of anogenital distance (AGD) index of pups, nipple retention of male pups and T4 of pups. The test substance had no endocrine disrupting potential in the pups under the condition of this study. Based on the results of this study, the NOAEL for reproductive toxicity of the test substance was considered to be 400 mg/kg bw/day for animals of both sexes. The NOAEL for developmental toxicity was considered to be 100 mg/kg bw/day for pups.

Effect on fertility: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

100 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

The study was conducted according to guideline and GLP.

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

An oral repeated dose toxicity study was conducted with the structural analogue substance p-methoxybenzyl acetate according to OECD 422 in rats. The test substance was administered via gavage to groups of 12 male and 12 female rats at concentrations of 0 (control), 25, 100 and 400 mg/kg bw/day. Males of the main group were dosed once daily for a total of 50 days (prior to mating for 2 weeks, during 2 weeks of mating and 22 days of post-mating), and females of the main group were dosed once daily for two weeks prior to mating, throughout gestation and for 13 days after delivery. Also, males and females of the recovery groups (6 animals per sex per group) were dosed for 50 days. All males of the main groups and all animals of the recovery groups survived the duration of the study. One dam at 0 mg/kg bw/day and one dam at 100 mg/kg bw/day were found dead in the main group. Salivation was observed in four females in the main group at 400 mg/kg bw/day and one male in the recovery group at 400 mg/kg bw/day during the dosing period, but it was not considered to have toxicological significance. The mass in the chest was a mammary gland tumor, however, this lesion was not considered to be related to the test substance since there was no dose-dependency and it could occur spontaneously. No test substance-related adverse effects were noted in the results of body weights, food consumption, estrous cycle, sensory function, motor activity, urinalysis, hematology, clinical chemistry, organ weights and thyroid hormone analysis in adult animals of the test substance-dosed groups. In one dead dam at 100 mg/kg bw/day, mineralization at slight/moderate severity in multiple organs was observed along with chief cell hyperplasia at slight severity in the parathyroid and fibrous osteodystrophy at slight/moderate severity in the femur and sternum. These findings were associated with hypercalcemia and hyperparathyroidism. However, the findings were considered to be not related to the test substance since they were observed in a single case at 100 mg/kg bw/day and post-partum hypercalcemia occurred rarely. In one dead dam of the control group, multiple organ failure was observed and it was due to dystocia accompanied by shock, which was associated with prolonged pregnancy. The viability index of Postnatal Day (PND) 4 was markedly decreased at 400 mg/kg bw/day. On PND 13, body weights of male pups and female pups were decreased at 400 mg/kg bw/day. No test substance-related adverse effects were noted in the results of the estrous cycle, mating period, mating index, gestation period, male and female fertility indexes, gestation index, post-implantation loss rate, live birth index, mean litter size, external examination of pups, sex ratio of pups and viability index of PND 0. No test substance-related effects were noted in the results of anogenital distance (AGD) index of pups, nipple retention of male pups and T4 of pups. The test substance had no endocrine disrupting potential in the pups under the condition of this study. Based on the results of this study, the NOAEL for reproductive toxicity of the test substance was considered to be 400 mg/kg bw/day for animals of both sexes. The NOAEL for developmental toxicity was considered to be 100 mg/kg bw/day for pups.

Effects on developmental toxicity

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

Based on available data on reproductive toxicity, the substance is considered to be not classified, according to Regulation (EC) No 1272/2008 (CLP), as amended for the ninth time in Regulation (EU) No 2016/1179.