2-ethylanthraquinone

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

The substance is not reprotoxic up to a dose level of 100 mg/kg bw/d in a study performed according to OECD Guideline 422 (Dunster, Watson, 2012).

In a supporting study, the NOEL for both reproductive potential of parental rats and growth/development of the next generation was judged to be 50 mg/kg bw/d (Reproduction/Develomental Toxicity Screening Test in Rats SR09204)

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

17 Nov 2010 - 31 Jan 2012

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)

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot No.of test material: 4808H
- Purity: 98.9 %
- Storage condition of test material: Stored in a tightly sealed container in a cool, dark place

Species:

rat

Strain:

other: Crl:CD(SD)

Details on species / strain selection:

Crl:CD(SD) rats produced by the Atsugi Breeding Center, Charles River Laboratories Japan, Inc. were used for the test. Rats are commonly used in toxicity tests, and this strain was selected because the Safety Research Institute for Chemical Compounds has abundant experience of using it.
52 males and 52 females (number ordered: 50 males and 50 females) aged 8 weeks were purchased on 17 August 2010. The weight range of the rats at the time of receipt was 244–283 g for males and 185–209 g for females.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 10 weeks
- Weight at study initiation: 339 – 406 g for males and 225 – 266 g for females.
- Housing: Bracket type cages with metal mesh floor (260 mm W x 380 mm D x 180 mm H) were used, and females that had copulated also had nesting trays and laboratory animal bedding.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 ± 3 ºC
- Humidity (%): 50 ± 20 %
- Air changes (per hr): 10–18 times/h
- Photoperiod (hrs dark / hrs light): 12 hours light/day

Route of administration:

oral: gavage

Vehicle:

other: 1 % methyl cellulose aqueous solution

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Preparation method:
The required amount of test substance was taken and placed in a pestle, and a very small quantity of 1% MC (about enough to cover the test substance) was added with care taken not to scatter the test substance. The test substance was mixed thoroughly into the medium by grinding with a pestle until the solution had a milky appearance.
Medium was added up to the prescribed concentration and the test substance was suspended using a stirrer. A glass vessel was used for the preparation vessel, and this was kept away from light as far as possible during preparation.

Frequency of preparation: Preparation was carried out at a frequency of once every 9 days or greater, and the solution was used for administration within 9 days of preparation.

Storage conditions: Dark, under refrigeration (measured temperature range 3.2–6.7ºC from date of first preparation to final storage date)

Storage location:Test substances storage room

Preparation precautions: Gloves, mask, and safety glasses were invariably worn during preparation, and the administration solution was handled in a fume cupboard.

Treatment of leftover administration solution: Leftover administration solution was collected as industrial waste for incineration.


VEHICLE
- Justification for use and choice of vehicle (if other than water): not specified
- Concentration in vehicle: 0.1 mg/mL, 50 mg/mL
- Lot/batch no. (if required): 8025083

Details on mating procedure:

- M/F ratio per cage: not specified
- Length of cohabitation: 14
- Proof of pregnancy: vaginal plug / sperm in vaginal smear

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

1. Equipment used
High-performance liquid chromatograph
UV-VIS Detector L-4200 Hitachi, Ltd.
Intelligent Pump L-6200 Hitachi, Ltd.
Column Oven L-5025 Hitachi, Ltd.
Autosampler AS-2000 Hitachi, Ltd.
Degasser ERC-3315α ERC Inc.
Data processor Empower 2 Nihon Waters K.K.
Electronic top pan balance ER-182A A&D Company Limited

2. Standard reference substance (stored in the dark in a refrigerator)
2-ethyl-9,10-anthraquinone (test substance)
Lot No. 4808H
Tokyo Chemical industry Co., Ltd

3. Test reagents
Tetrahydrofuran (no stabiliser added) For use in high-performance liquid chromatograph
Wako Pure Chemical Industries, Ltd
Distilled water For use in large-volume preparative liquid chromatography
Kanto Chemical Co., Inc.

4. Preparation (Prepared to the proportions given below, preparation day calculated as Day 0)
(1) Standard solution (approx. 10 µg/mL)
To prepare a solution of approximately 1,000 µg/ml 2-ethyl-9,10-anthraquinone, 0.02 g were accurately weighed into a 20 mL measuring flask and tetrahydrofuran was added to dissolve the substance and bring to volume (standard stock solution). 0.5 mL of this solution were added to a 50 mL measuring flask and tetrahydrofuran was added to bring to volume to a solution of approximately 10 µg/ml (standard solution). The solution was prepared once and injected into the HPLC 3 times. Following preparation, the solution was used the same day.
(2) Sample solution
With regard to the number of sampling points for the test substance solution, samples were taken from 3 points around the middle part for the concentration confirmation test, and samples were taken from three points in each of the top, middle, and bottom part, a total of 9 points,for the homogeneity test. The concentration of the middle part in the homogeneity test was taken as the analysis result for concentration at the time of preparation in the stability test.
1) Each test substance solution was sampled and tetrahydrofuran was added to give a final concentration of the test substance in the range 0.500 – 50.0 µg/mL (if possible near to 10 µg/mL) and a percentage of the medium of 10 % or less, and this was taken as the sample solution. Where preparation was carried out with dilution in 2 stages, the concentration of the test substance in the first dilution was 1,000 µg/mL or less.
2) Sample solution was prepared once for each point, and each sample solution was injected once into the HPLC.
(3) Mobile phase
The mobile phase was prepared by adding 500 mL tetrahydrofuran to 500 mL distilled water and mixing thoroughly. After preparation, this was stored at room temperature and used within 12 days.
(4) Autosampler wash solution
The autosampler wash solution was prepared by adding 700 mL tetrahydrofuran to 300 mL distilled water and mixing thoroughly. After preparation, this was stored at room temperature and used within 14 days.
(5) Injection solution for washing
The injection solution used for washing was tetrahydrofuran alone.

5. HPLC conditions
Column: GL-Pack Nucleosil 100-10C18, 4.0 mm I.D. x 250 mm,
G L Sciences Inc.
Mobile phase: Tetrahydrofuran / distilled water (500:500)
Autosampler wash solution: Tetrahydrofuran / distilled water (700:300)
Injection solution for washing: Tetrahydrofuran
Measurement wavelength: 257 nm
Column temperature: 40 ºC
Flow rate: 1 mL/min
Injection amount: 20 µL
Autosampler temperature: Room temperature
Analysis time: 12 min

6. System conformance test
On each measurement day, the standard solution was repeatedly injected 6 times. The coefficient of variance for the 2-ethyl-9,10-anthraquinone peak area and for the retention time were calculated.

7. Calculations
The measured concentration of each sample solution was determined by means of a calibration curve drawn from the peak area and the concentration of the standard solution using Empower 2, and the concentration of test substance in the solution, coefficient of variance, content percentage, and residual ratio were calculated using the formulae mentioned in the report.

8. Display of numerical values
(1) Concentration of the test solution was calculated using the values from weighing, and calculated values were rounded to 3 significant digits.
(2) Concentration of the test substance in the prepared solutions was rounded to 3 significant digits.
(3) The coefficient of variance, the content percentage, and the residual ratio were rounded to the first decimal place.

9. Judgement criteria
(1) Concentration confirmation test: Content percentage 90–110 %, coefficient of variance ≤ 5 % was considered acceptable.
(2) Stability test: Residual ratio 90–110 %, coefficient of variance ≤ 5 % was considered acceptable.
(3) Homogeneity test: Coefficient of variance ≤ 5 % was considered acceptable.
(4) System conformity test: Coefficient of variance ≤ 2 % was considered acceptable. In the present test, the peak area was 0.2 – 0.4 % and retention time was 0.0 – 0.2 %, both of which were within the acceptable criteria.

Duration of treatment / exposure:

Males: 42 days
Females: maximum 53 days

Frequency of treatment:

Once daily

Dose / conc.:

0 mg/kg bw/day

Dose / conc.:

2 mg/kg bw/day

Dose / conc.:

10 mg/kg bw/day

Dose / conc.:

50 mg/kg bw/day

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
The dosages were selected on the basis of the results of a 28-day repeated oral dose toxicity test of 2-ethylanthraquinone (purity of test substance: 99.16%, medium: 0.5% carmellose sodium aqueous solution with added 0.1% polysorbate 80, administration dosages: 10, 50, and 250 mg/kg/day).4) The principal toxicity of 2-ethylanthraquinone is changes in red blood cells thought to be haemolytic anaemia, which was found in males at 10 mg/kg or greater and in females at 250 mg/kg. Also, liver effects (centrilobular hypertrophy of hepatocytes and, in cases in which this was seen to a marked degree, irregular size of nuclei) were seen in males and females at 50 mg/kg or greater. Refer to toxicity report in section 1 for detailed toxic changes. Taking the above information, the administration period of the present test, and the perinatal period into consideration, a dose of 50 mg/kg/day at which general toxicological effects (hepatic changes) were found was taken as the high dose, and using a common ratio of 5 the lower doses were set at 10 mg/kg/day and 2 mg/kg/day. A control group was also established, in which medium only was administered by the same method.

- Other:
Administration method and administration route: Oral gavage

Number of administrations: Once daily, repeated administration.

Administration schedule: 09:00–12:00. Maternal rats during delivery were dosed after completion of delivery.

Administration period:
Males: 14 days prior to mating and 28 days after mating, total 42 days.
Females: 14 days prior to mating, during the mating period until copulation, during gestation, and until lactation day 3 (maximum 53 days).

Administration volume: The volume of administration solution was calculated on the basis of body weight measured on the measurement day nearest to the administration day.

Rationale for selection of administration method, administration route, number of administrations, and administration period: The test method guidelines were used as reference.

Positive control:

Not applicable

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: No data

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule:
For Males: With the start of administration taken as administration day 1, the period was from administration day 1 to the autopsy day on the day after administration day 48.
For Females: From administration day 1 to the autopsy day.

BODY WEIGHT: Yes
- Time schedule for examinations:
For Males: With the start of administration taken as administration day 1, weight was measured before administration on administration days 1, 2, 5, 7, 10, 14, and every 7 days thereafter, on the day of final administration, and on the autopsy day.
For Females: With the start of administration taken as administration day 1, the day of copulation as gestation day 0, and the day of completion of delivery as lactation day 0, measurements were made on the following days:
Before administration on administration days 1, 2, 5, 7, 10, 14;
Before administration on gestation days 0, 1, 3, 5, 7, 10, 14, 17, and 20;
Before administration on lactation days 0, 1, and on lactation day 4 (autopsy day);
In cases of delayed delivery, on gestation day 26 (autopsy day).
During the mating period, measurement was carried out on the same day as the male mate partner in order to calculate the amount of administration liquid.

Oestrous cyclicity (parental animals):

Oestrus/Estrous cycle test
Number of rats: All females
Period: From start of administration day to copulation day
Method: Vaginal smear samples were prepared with Giemsa stain, and oestrus cycle stage was judged by optical microscope examination.
Judgement: The period of the oestrus cycle was calculated, with normal oestrus taken to be 2 or more repetitions of the stages of the oestrus cycle (preoestrus, oestrus, metoestrus, and dioestrus), each with a length of 4 to 6 days. Dioestrus observed for more than 7 consecutive days was taken to be persistent dioestrus, and judged to be an abnormality.

Litter observations:

Observation of general appearance of pups
Number of rats: All rats
Frequency: Once per day
Period: From lactation day 0 to lactation day 4
Observation method: Survival or death were checked, and general appearance and external appearance were observed.
Procedure for dead pups: Immediately after dead pups were found, an autopsy was performed and the whole body was fixed and preserved in 10 % buffered formalin.

Measurement of body weight of pups
Number of rats/period: All live pups were weighed on lactation days 0, 1, and 4.
Measurement method:Males and females in each litter were weighed separately using an electronic top pan balance (GX-2000, A&D Company Limited), and the combined weight for each sex was recorded to 0.1 g.
The mean weight of males and of females per litter was calculated.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals. Carried out on the day after administration day 42.
- Maternal animals: All surviving animals. Carried out on lactation day 4. In cases of delayed delivery, on gestation day 26


GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera. The liver, kidneys, spleen, prostate gland, and seminal vesicles (including the coagulating glands) and sites of gross abnormality (ileum) were fixed and preserved in 10 % buffered formalin. In addition, the left and right testes and the epididymis were fixed in Bouin solution and preserved in 70 % ethanol. With paired organs, both left and right were preserved.


HISTOPATHOLOGY / ORGAN WEIGHTS
The tissues indicated below were prepared for microscopic examination and weighed, respectively.
Male: Left and right testes (including those classified as at the stage of spermatogenesis), epididymis, sites of gross abnormality (ileum).
Females: Left and right ovaries, sites of gross abnormality (ileum)

Postmortem examinations (offspring):

Autopsy of pups
Period/number of rats: Performed on all pups on lactation day 4.
Autopsy method: The outer surface of the body (including inside the oral cavity) was inspected and the pups were euthanized by the carbon dioxide inhalation method, and organs and tissues from the whole body were grossly examined. If an abnormality was found, the whole body was fixed and preserved in 10 % buffered formalin.

Statistics:

Means and standard deviations for each dosage group were calculated from the results for body weight, body weight increase and body weight increase index, amount of food consumed, absolute weight and relative weight of organs, spermatogenesis stage, length of oestrus cycle, number of gestation corpora lutea, number of implantation sites, number of births, number of live and dead births, delivery index, live birth index, sex ratio, gestation period, number of live pups on lactation day 4, and pup survival rate. Bartlett’s test was carried out for each item to test for homogeneity of variance. Where homogeneity of variance was found, a one-way analysis of variance (ANOVA) was performed, and where unequal variance was found analysis was carried out using the Kruskal-Wallis test. Where significant differences were found in the ANOVA, comparison with the control group was carried out using Dunnett’s test. Where significant differences were found with the Kruskal-Wallis test, comparison with the control group was carried out using the Mann-Whitney U test. In the weight of pups by gender, the litter was taken as the sample unit.
The level of significance in tests comparing to the control group was set at 5%. The methods for displaying statistical data are shown at the head of the Individual Data section.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Males: Red coloured urine was observed sporadically in all 12 individuals in the 50 mg/kg group during the administration period. No abnormality related to administration of the test substance was found in rats in any of the other groups. Maxillary incisor fracture was found in one individual in the 2 mg/kg group on administration days 37–42.
Females: Red coloured urine was observed sporadically in 5 of the 12 individuals in the 50 mg/kg group during the administration period (before the mating period, during the mating period, and during the gestation period). No abnormality was found in rats in any of the other groups.
The red coloured urine was tested with urine test paper (Multistix, Siemens Healthcare Diagnostics), and the reaction to occult blood was negative.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Males: Body weight of the 50 mg/kg group on administration days 7–10 was significantly lower than that of the control group. No significant differences with respect to the control group were found in either weight gain or weight gain index during the administration period.
Females: No significant differences with respect to the control group was found in body weight, weight gain, or weight gain index in any of the test substance administration groups before the mating period, during the gestation period, and during the lactation period.

Food efficiency:

effects observed, treatment-related

Description (incidence and severity):

Males: Food consumption was significantly lower in the 50 mg/kg group than the control group on administration days 1–10. No significant difference with respect to the control group was found in the 10 mg/kg and lower administration groups.
Females: Food consumption was significantly lower in the 50 mg/kg group than the control group on administration days 1–2. No significant difference with respect to the control group was found during the gestation period or the lactation period in any of the test substance administration groups.

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Males: In the one individual in the control group in which reduced size of the testis and epididymis on one side was found at the autopsy, severe atrophy of the seminiferous tubules and mild oedema of the stroma were found. In addition, the sperm count in the epididymis was severely reduced and moderate cell debris was found in the seminiferous tubules. No abnormality was found in any other rats.
Other than this, the ileal diverticulum found by gross examination in one individual in the 50 mg/kg group was an insubstantial change.

Females: In the ovaries, mild corpora lutea cysts were found on one side in one individual in the control group, and were found on both sides in one individual in the 50 mg/kg group.
Other than this, in the kidney of the one individual in the 50 mg/kg group in which gross changes were found, there was slight renal pelvis dilation and slight regeneration in the tubular epithelium.

Histopathological findings: neoplastic:

not examined

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Delivery and lactation in maternal rats
The results for delivery and lactation are shown in Table 17 and 18 and Individual Data 9-1 to 10-4.
In the 10 mg/kg group the gestation period was significantly longer and the number of corpora lutea was significantly lower than the control group. No significant differences with respect to the control group were found in number of implantation sites, implantation index, live birth index, delivery index, or nursing index in any of the test substance administration groups.
No significant differences with respect to the control group were found in number of pups born, number of live pups, sex ratio, and live birth index on lactation day 0, or number of live pups, sex ratio, and live birth index on lactation day 4 in any of the test substance administration groups.

Reproductive function: oestrous cycle:

effects observed, non-treatment-related

Description (incidence and severity):

One individual in the 50 mg/kg group showed extended dioestrus, but the oestrus cycle recovered after 12 days and the individual copulated. As no tendency toward prolongation of the oestrus cycle was found in the other rats in the same group, it is considered highly likely that this was caused by false pregnancy as a result of the vaginal smear procedure rather than being a result of administration of the test substance.

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

Description (incidence and severity):

With regard to the reproduction performance of the parental rats, no changes related to administration of the test substance up to a dose of 50 mg/kg were found in length of the oestrus cycle, incidence of oestrus abnormalities, copulation index, fertilisation index, gestation period, number of corpora lutea, number of implantation sites, implantation index, live birth index, delivery index, or nursing index.

Key result

Dose descriptor:

NOEL

Effect level:

10 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

body weight and weight gain

food consumption and compound intake

Key result

Dose descriptor:

NOAEL

Effect level:

50 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

mortality

body weight and weight gain

food efficiency

organ weights and organ / body weight ratios

gross pathology

histopathology: non-neoplastic

reproductive function (oestrous cycle)

reproductive performance

Key result

Critical effects observed:

no

Clinical signs:

no effects observed

Description (incidence and severity):

No effects of administration of the test substance were found in general appearance in any of the test substance administration groups.
No abnormalities in external appearance were found in any of the groups of rats.

Mortality / viability:

mortality observed, non-treatment-related

Description (incidence and severity):

The number of pup deaths until lactation day 4 were: 1 male and 3 females in the control group, 2 males and 1 female in the 2 mg/kg group, 4 males and 4 females in the 10 mg/kg group, and 2 males and 1 female in the 50 mg/kg group. In addition, no milk band was found in the abdomen of several pups in the control, 2 mg/kg, and 10 mg/kg group. One pup in the 10 mg/kg group was found to be missing the tail due to physical trauma on lactation day 0. No dose dependency of frequency was found for any of these changes.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

The body weight of pups on lactation day 0 was significantly greater in the 10 mg/kg group than the control group, but this was not a dose-related change. No significant difference with respect to the control was found in body weight of pups until lactation day 4 in any other test substance administration group.

Food efficiency:

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:

effects observed, non-treatment-related

Description (incidence and severity):

In the live pups on lactation day 4, one male only in the 10 mg/kg group showed one-sided renal pelvis dilation and dilation of the ureter, and these were not dose-related occurrences.
Of the pups that died between lactation day 0 and lactation day 4, no abnormalities were found in the pups that could be examined.

Histopathological findings:

not examined

Other effects:

no effects observed

Description (incidence and severity):

In the growth and development of pups, no changes related to administration of the test substance up to a dose of 50 mg/kg were found in the sex ratio.

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

not examined

Key result

Dose descriptor:

NOEL

Generation:

F1

Effect level:

50 mg/kg bw/day

Based on:

test mat.

Sex:

not specified

Basis for effect level:

viability

clinical signs

body weight and weight gain

gross pathology

other: Sex ratio

Key result

Reproductive effects observed:

no

Conclusions:

On the basis of the results mentioned above, i.e. red urine in males and females, decreased food consumption in males and females, and suppressed weight gain in males were found at 50 mg/kg/day, the no observable effects limit (NOEL) on parental rats for repeated doses of 2-ethyl-9,10-anthraquinone under the present test conditions was judged to be 10 mg/kg/day. Because the effects observed at 50 mg/kg/day were not considered adverse, the NOAEL was 50 mg/kg/day for the parental rats. The NOEL for reproduction performance of parental rats and for growth and development of pups was judged to be 50 mg/kg/day.

Executive summary:

Crl:CD(SD) rats were dosed orally once a day with 2-ethyl-9,10-anthraquinone at 0 (control, 1 % methyl cellulose aqueous solution), 2, 10, and 50 mg/kg in groups of 12 males and 12 females for each dose. Males were dosed for 42 days, comprising 14 days prior to mating and 28 days after mating. Females were dosed for 14 days prior to mating, during the mating period until copulation, during gestation, and for 3 days of lactation. The toxicity to reproduction, including gonadal function, mating behaviour, fertilization, and birth, as well as the effects on development and growth of the subsequent generation were studied.

 

I. Parental rats

1.    In both males and females, red urine (negative occult blood reaction) was occasionally seen during administration of 50 mg/kg of the test substance. Males and females showed significant reduction in food consumption in the initial stage of administration, and suppression of weight increase was found in males.

2.    No effect from administration of the test substance up to a dose of 50 mg/kg was found in the organ weight or the post mortem examination of male reproductive organs.

3.    No effect from administration of the test substance up to a dose of 50 mg/kg was found in either males or females in the histopathological examination of the testes, the epididymis, and the ovaries, or in spermatogenesis at a dose of 50 mg/kg.

 

II. Reproduction of the parental rats and growth/development of pups

1.    No effect from administration of the test substance up to a dose of 50 mg/kg was found in either males or females in the mating period, the oestrus cycle abnormality incidence rate, the copulation index, the fertilization index, the gestation period, the number of corpora lutea, the number of implantation sites, the implantation index, the live birth index, the delivery index, or the nursing index.

2.    No effect from administration of the test substance up to a dose of 50 mg/kg was found in either males or females in the number of pups born, number of live pups on lactation day 0, sex ratio, or live birth index.

3.    No effect from administration of the test substance up to a dose of 50 mg/kg was found in either males or females in the general appearance, body weight, and autopsy findings of pups.

 

From the foregoing, as red urine was found in males and females, males and females showed initial reduction in food consumption, and males showed suppression of weight gain at 50 mg/kg, the No Observed Effect Level (NOEL) for repeated administration of 2-ethyl-9,10-anthraquinone to parental rats under the present experimental conditions was judged to be 10 mg/kg. Because the effects observed at 50 mg/kg/day were not considered adverse, the NOAEL was 50 mg/kg/day for the parental rats. The NOEL for both reproductive potential of parental rats and growth/development of the next generation was judged to be 50 mg/kg.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

100 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

GLP guideline study, Klimisch 1

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

A valid OECD 422 reproduction/development toxicity screening study (Dunster, Watson, 2012)  has been conducted with the substance. The substance proved to be not reprotoxic up to a dose level of 100 mg/kg bw/d.

Short description of key information:

The substance is not reprotoxic up to a dose level of 100 mg/kg bw/d.

Justification for selection of Effect on fertility via oral route:

The selected study was performed under GLP and in accordance with OECD TG 422. No other studies are available.

Effects on developmental toxicity

Description of key information

Embryo-fetal survival, growth and development in rats were unaffected by maternal treatment with 2-Ethylanthraquinone.

Based on the results obtained in the main study of embryo-fetal development (Stannard, 2016), it was concluded that the dose level of 15 mg/kg/day represented the No Observed Adverse Effect Level (NOAEL) for maternal toxicity based on body weight and weight gain and the dose level of 50 mg/kg/day represented the NOAEL for embryo-fetal survival, growth and development.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

50 mg/kg bw/day

Study duration:

subchronic

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

Justification for classification or non-classification

The substance did not give any indication of reprotoxic potential and developmental toxicity, thus no classification of the test item is warranted.