Bis(2-chloroethyl) ether

Toxicity to reproduction

Administrative data

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

Remarks:

Study conducted on behalf of the Japanese Ministry of Health, Labour and Welfare

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Bis(2-chloroethyl) ether

EC Number:

203-870-1

EC Name:

Bis(2-chloroethyl) ether

Cas Number:

111-44-4

Molecular formula:

C4H8Cl2O

IUPAC Name:

1-chloro-2-(2-chloroethoxy)ethane

Test material form:

liquid

Specific details on test material used for the study:

TEST MATERIAL
- Name (as cited): 2,2'-Dichlorodiethyl ether
- Purity: 99.50% (GC)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: stored at room temperature in a dark place

Test animals

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Japan (Hino Breeding Center)
- Females (if applicable) nulliparous and non-pregnant: [yes/no]
- Age at study initiation: 9 weeks old
- Weight at study initiation: males = 333.0–370.1g ; females = 205.3–250.1g
- Housing: biotron barrier system
- Diet: ad libitum
- Water ad libitum
- Acclimation period: eight days, including six days of quarantine

DETAILS OF FOOD AND WATER QUALITY:
- Feed: Oriental Kobo Kogyo solid feed, MF, lot nos. 060306 and 060509
- Water: Hita City tap water (chlorine added)
Feed and water confirmed to be within the reference values set down by the "Contaminant Limits in Feed and Media" in the EPA’s harmful substance guidelines

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21–25°C
- Humidity (%): 40–70%
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 19h dark / 7h light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

olive oil

Remarks:

Fujimi Seiyakusho, lot no. 0380HS

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test substance was prepared by weighing a known amount of 2,2'-dichloroethyl ether in olive oil to reach a final concentration of 0.3% (w/v). Solutions at 0.06 and 0.012% (w/v) were diluted from the 0.3 w/v% solution with olive oil. New stock solution were prepared weekly and stored in a cool dry place before dosing.

VEHICLE
- Justification for use and choice of vehicle: the substance was considered to be insoluble in pure water
- Concentration in vehicle: 0.06, 0.012 and 0.3% (w/v)
- Amount of vehicle: 5 mL/kg bw

Details on mating procedure:

- M/F ratio per cage: one-to-one
- Length of cohabitation: until mating but no longer than 14 days
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy
- After successful mating each pregnant female was caged alone

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

The uniformity of the test substance in the prepared solution was measured by taking n = 1 samples from the top, middle, and bottom layers of the prepared 0.3 and 0.12 w/v% solutions, pretreating the samples, and measuring the test substance concentration once each using gas chromatography (GC).
Stability of the test substance in the prepared solution was measured by storing the prepared solutions whose uniformity was confirmed in a cool, dark place, taking n = 1 samples from the middle layer after storage for seven and 14 days, pretreating these, and then using GC to measure the test substance concentrations once each.
Concentration of the test substance in the prepared solution was measured by taking n = 1 samples from the middle layer after preparation of the initially prepared 0.3, 0.06, and 0.012 w/v% solutions, pretreating these, and then using GC to measure the test substance concentrations once each.
The 0.3 and 0.012 w/v% solutions were confirmed to be uniform and stable after storage for 14 days in a cool, dark place. The test substance concentration in the prepared solution used for the initial dosing was confirmed to be 100±10% for all concentrations in the set values for 0.3, 0.06, and 0.012 w/v%.

Duration of treatment / exposure:

Males: 42 days
Females: 42-45 days

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0.6 mg/kg bw/day (actual dose received)

Doses / concentrations 2

Dose / conc.:

3 mg/kg bw/day (actual dose received)

Doses / concentrations 3

Dose / conc.:

15 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dose selection was based on a range finding study.
Three male and three female rats from each group were used to conduct a repeated oral dosing for a period of 14 days at doses of 0, 1, 5, 20, and 100 mg/kg bw/day.
Observations: Increase in hematocrit at 5 mg/kg bw/day and higher. At 20 mg/kg bw/day and higher, low spontaneous locomotion and low respiratory rate were observed. At 100 mg/kg bw/day, weight loss, staggering gait, abnormal gait, coma, feeding problems, low stool amount, low body temperature, lid-closure, deep breathing, mucous stool, prone and recumbent positions, and staining of the lower abdomen and around the anus. All test animals died at this dose.
Dose selection for the full test: Based on observations from the range finding study, the maximum dose was set at 15 mg/kg bw/day with two other doses at 3 and 0.6 mg/kg/day. The doses were slected based on the fact that low spontaneous locomotion and low respiratory rate was observed at 20 mg/kg bw/day and that the dosing period would be longer.

- Rationale for animal assignment: randomized extraction by weight, so that members of each group were of approximately the same weight

- Rationale for selecting satellite groups: 5 males and females (unmated) from the 0 and 15 mg/kg bw/day groups

- Post-exposure recovery period in satellite groups: 14 days

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule:
Males: twice a day from the first day of dosing until the day before necropsy
Females: twice a day from the first day of dosing until the fourth day of delivery, including the delivery state and nursing state
Recovery period: once a day during the recovery period until the day before necropsy

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: observed in a blind fashion once prior to dosing and once a week after dosing had started

BODY WEIGHT: Yes
- Time schedule for examinations: Males and females were measured once a week during the habituation period and on the day of grouping. After grouping, males were measured on dosing day 1, 3, 7, 14, 21, 28, 35, 42, and 43 (day of removal). The females were measured on dosing day 1, 3, 7, and 14, and gestation day 0, 7, 14, 17, and 20 during the gestation period, and, after delivery, postpartum day 0 (day of delivery), 4, and 5 (day of removal). During the recovery period, both males and females were measured on day 1, 3, 7, 14, and 15 of recovery.

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

OPHTHALMOSCOPIC EXAMINATION: Not specified

HAEMATOLOGY: Yes
- Time schedule for collection of blood: the last day of the dosing period and the last day of the recovery period
- Anaesthetic used for blood collection: Yes (ether)
- Animals fasted: Yes
- How many animals: 5 animals/sex/dose group

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: the last day of the dosing period and the last day of the recovery period
- Animals fasted: Yes
- How many animals: 5 animals/sex/dose groupd.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule: observed in a blind fashion once prior to dosing and once a week after dosing had started
- Dose groups that were examined: all dose groups
- Battery of functions tested: reactivity testing, posture, motor activity, respiration, lid closure, gait, tremor/twitch/convulsion, and presence/absence of stereotypic behaviour and abnormal behaviour

IMMUNOLOGY: No

Oestrous cyclicity (parental animals):

For all females, vaginal plaque was taken from the day dosing started until the day mating was confirmed. Giemsa staining was used for optical microscopy. The average number of days in the oestrous cycle was calculated between oestrus days between the first and 14th days of dosing. The incidence of abnormal oestrous cycles (individuals not exhibiting regular oestrous cycles) was also calculated.

Statistics:

Significant differences with the control group in the parents’ mating rate, insemination rate, conception rate, implantation rate, pre-implantation embryo loss rate, post-implantation embryo loss rate, birth rate, delivery rate, day 0 live birth rate and day 4 live birth rate were tested using the chi-square test (or Fisher's exact test if the peripheral frequency was 10 or less).
The Kruskal-Wallis rank sum test method was used to test significance of the birth rate, live birth rate, out of table abnormality rate, and day 4 survival rate of pups in all groups, followed by a test of significant difference with the control groups using the Dunnett multiple comparison method.

Reproductive indices:

FERTILITY TEST:
Mating was checked daily during the mating period. If sperm was found in the vaginal plug or the vaginal plaque, mating was assumed to have been performed, and that day was established as day 0 of pregnancy. The following indices were calculated:
- Mating rate: (number of copulating animals/number of animals placed together) × 100
- Insemination rate: (number of males that impregnated a female/number of mating males) × 100
- Conception rate: (number of pregnant females/number of mating males) × 100
- Days required for mating
- Implantation rate: (number of implantation marks/number of corpora lutea of pregnancy) × 100
- Pre-implantation embryo loss rate: [(number of corpora lutea of pregnancy – number of implantation marks)/number of corpora lutea of pregnancy] × 100
- Post-implantation embryo loss rate: [(number of implantation marks – number of pups born)/number of implantation marks] × 100

DELIVERY AND NURSING:
The following indices were calculated:
- Gestation period (number of days from the day mating was confirmed until the day delivery was complete)
- Birth rate: (number of females birthing live pups/number of pregnant females) × 100
- Delivery rate: (number of birthed pups/number of implantation marks) × 100

Offspring viability indices:

Number of births, number of dead pups, number of live births, sex and number of live births outside the table were examined on the day of birth (calculated starting on day 0 after birth). The general state, the number of pups alive and the number of pups who died was observed through day 3 after birth, and on the fourth day after birth (slaughter date) the number of pups, the sex, the number of live pups outside the table, the number of dead pups, and the number of dead pups outside the table were examined, and the following indices were calculated:
- Birth rate: (number of live births/number of implantation marks) × 100
- Live birth rate: (number of live births/number of births) × 100
- Day 0 live pup ratio: number of live male pups on day 0/number of live pups on day 0
- Out of table abnormality rate: (number of live births having out of table abnormalities/number of examined live births) × 100
- Day 4 survival rate: (number of live pups four days after birth/number of births on day of birth) × 100
- Day 4 live pup ratio: number of live male pups on day 4/number of live pups on day 4

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

DOSING PERIOD
Salivation was observed in one female each in the 3 and 15 mg/kg groups before mating was confirmed. Besides this, low spontaneous locomotion, respiratory rate and body temperature were seen on dosing day 22 in one animal in the 0.6 mg/kg group during the gestation period. This animal died during delivery the next day. Reddish urine was observed in one animal in the 15 mg/kg group.

RECOVERY PERIOD
No abnormalities were seen in any of the males or females.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

One animal in the 0.6 mg/kg group died during delivery.

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

AT THE END OF DOSING PERIOD
Among males, low mean corpuscular volume and mean corpuscular haemoglobin were observed in the 3 mg/kg and higher groups. No significant differences were seen in the 0.6mg/kg group.
Among females, a high lymphocyte ratio was seen in the 0.6 mg/kg group, but no related changes were observed, so this was not thought to be a toxicologically important change. No significant differences were seen in the 3 and 15 mg/kg groups.

AT THE END OF RECOVERY PERIOD
No significant differences were seen in the male groups receiving the test substance.
Among females, high red blood cell and platelet counts were observed in the 15 mg/kg group, and a low reticulocyte count ratio and neutrophil ratio were observed.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

AT THE END OF DOSING PERIOD
No significant differences were seen in the test substance dosing groups among males or females.

AT THE END OF RECOVERY PERIOD
Among males, high chlorine values were seen in the 15 mg/kg group. Among females, high urea nitrogen values were observed in the 15 mg/kg group, but no relevant changes were seen, so this was thought to be an incidental change.

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Description (incidence and severity):

Although continuous resting was observed in one animal in the 3 mg/kg group, the animal was normal until collection of the vaginal plaque on day 16, so this was deemed to be caused by a phantom pregnancy. No abnormalities were seen in any other animals.

Reproductive function: sperm measures:

not examined

Reproductive performance:

effects observed, treatment-related

Description (incidence and severity):

All females were pregnant in the control and treated groups. There was no effect on gestation length, the number of corpora lutea or the number of implantation sites. No differences were observed on the gestation index (Number of pregnant females with live pups / Number of pregnant females ×100), on the implantation index (Number of implantation sites / Number of corpora lutea × 100) or on preimplantation loss.

A lower delivery index (Number of pups born / Number of implantation sites × 100) was observed in test animals treated with 0.6 and 15 mg/kg bw/day. However, no effect was observed at 3 mg/kg bw/day and the connection with dose is thus unclear. The effect on delivery rate was considered incidental in the 0.6 and 3 mg/kg bw/day, while it was considered to be an effect of toxicity of the test substance at 15 mg/ kg bw/day.

Higher post-implantation loss ((Number of implantation sites - Number of live pups on postnatal day 0) / Number of implantation sites x 100) was observed at 0.6 mg/kg bw/day and above (7.2, 15.6, 17.0 and 18.7%, in the control, 0.6, 3, 15 mg/kg bw/day) group, respectively). Similarly, lower birth index (Number of live pups on postnatal day 0 / Number of implantation sites × 100) was observed at 0.6 mg/kg bw/day and above (92.8, 84.4, 83.0 and 81.3%, in the control, 0.6, 3, 15 mg/kg bw/day) group, respectively). However, it is these observation originates from toxicity towards germ cells of the P0 generation, from embryotoxicity or, more generally, from maternal toxicity. In addition, no effect was observed on measured parameters and significant differences were only observed on derived indices.

See "Any other informations on results incl. tables" for details

Effect levels (P0)

1

Key result

Dose descriptor:

NOAEL

Remarks:

Parental toxicity

Effect level:

15 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No adverse effect at the highest dose

2

Key result

Dose descriptor:

NOAEL

Remarks:

Reproductive performance

Effect level:

3 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: reduced delivery index at 15 mg/kg bw/day

3

Key result

Dose descriptor:

LOEL

Effect level:

< 0.6 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: slighlty higher post-implantation loss and lower birth index at 0.6 mg/kg bw/day

Results: F1 generation

General toxicity (F1)

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

A drop in body temperature in three litters was observed in the 3 mg/kg group, a wound to the end of the tail was observed in one animal in nine in one litter in the 15 mg/kg group, and a drop in body temperature was observed in another litter in the same group. These observations were considered incidental.

Dermal irritation (if dermal study):

not examined

Mortality / viability:

mortality observed, non-treatment-related

Description (incidence and severity):

The live birth index (number of pups born alive/number of pups born x 100) was slightly lower in the 3 mg/kg bw/day (88.8%) compared with the concurrent contrl (96%). However, without any dose relationship and any similar finding at the high dose of 15 mg/kg bw/day, this was considered incidental.

Higher (98.1%) day 4 survival rates (i.e. viability index corresponding to the number of pups alive on PND 4/number of pups born alive x 100) as compared to control (89.9%) was observed in the 0.6 mg/kg bw/day group. At the opposite, a significant decrease in the viability index was found in the 3 mg/kg group (80.1%), while no significant effects were detected at 15 mg/kg bw/day (87.8%). Without any dose relationship and without any significant effect observed at 15 mg/kg bw/day, these observations were considered as incidental.

Higher post-implantation loss ((Number of implantation sites - Number of live pups on postnatal day 0) / Number of implantation sites x 100) was observed at 0.6 mg/kg bw/day and above (7.2, 15.6, 17.0 and 18.7%, in the control, 0.6, 3, 15 mg/kg bw/day) group, respectively). However, it is unclear if post-implantation originates from toxicity towards germ cells of the P0 generation, from embryotoxicity or, more generally, from maternal toxicity.

Significant differences related to pups mortality parameters were only observed on derived indices. No significant differences were observed on measured parameters (number of live pups (male or female) at birth or at PND 4). The mortality observed is not considered to be treatment related.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No significant differences were seen in the weights on the day of birth and four days later in groups receiving the test substance.

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

Effect levels (F1)

Key result

Dose descriptor:

LOEL

Generation:

F1

Effect level:

< 0.6 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: slighlty higher post-implantation loss that may originate from embryotoxicity.

Overall reproductive toxicity

Reproductive effects observed:

yes

Lowest effective dose / conc.:

0.6 mg/kg bw/day (actual dose received)

Treatment related:

yes

Relation to other toxic effects:

not specified

Dose response relationship:

yes

Any other information on results incl. tables

## Reproductive parameters in parental rats treated orally with 2,2'-dichlorodiethylether in the combined repeated dose and reproductive/developmental toxicity screening test:

	Dose (mg/kg bw/day)
	0	0.6	3	15
Number of mated pairs	12	12	12	12
Number of of copulated pairs	12	12	12	12
Number of of pregnant females	12	12	12	12
Copulation index (%)*	100	100	100	100
Fertilization index (%)**	100	100	100	100
Conception index (%)***	100	100	100	100
Pairing days until copulation (Mean ± SD)	2.7 ± 1.0	2.2  ± 1.0	2.0 ± 0.9	2.0 ± 0.9

* (Number of copulated pairs /Number of mated pairs) × 100

** (Number of impregnated males /Number of males in copulated pairs) × 100

*** (Number of pregnant females /Number of females in copulated pairs) × 100

## Postnatal course of rat litters whose parents treated orally with 2,2'-dichlorodiethylether in the combined repeated dose and reproductive/developmental toxicity screening test:

	Dose (mg/kg bw/day)
	0	0.6	3	15
Number of pregnants	12	12	12	12
Gestation length in days (Mean ± SD)	21.9 ± 0.5	21.9 ± 0.3	22.1 ± 0.5	22.2 ± 0.4
Number of dams with live newborns:
- on postpartum day 0	12	11	12	12
- on postpartum day 4	11	11	9	11
Number of corpora lutea (Mean ± SD)	15.3	15.9	15.7	15.7
Number of implantation sites (Mean ± SD)	15.1	15.5	15.2	15.2
- Gestation index (%)^1	100 (12/12)	100 (12/12)	100 (12/12)	100 (12/12)
- Implantation index (%)^2	98.9 (181/183)	97.4 (186/191)	96.8 (182/188)	96.8 (182/188)
- Delivery index (%)^3	96.7 (175/181)	87.1 (162/186)**	93.4 (170/182)	88.5 (161/182)**
Postnatal day 0
- Number of pups born (Mean ± SD)	14.6 ± 1.6	14.7 ± 1.7	14.2 ± 1.6	13.4 ± 3.1
- Number of live pups (Mean ± SD)	14.0 ± 2.2	14.3 ± 2.2	12.6 ± 2.9	12.3 ± 3.1
- Number of live males (Mean ± SD)	6.9 ± 2.1	7.3 ± 2.1	6.9 ± 2.9	6.3 ± 2.6
- Number of live females (Mean ± SD)	7.1 ± 2.7	7.0 ± 2.1	5.7 ± 2.1	6.1 ± 2.4
- Birth index (%)^4	92.8 (168/181)	84.4(157/186)*	83.0(151/182)**	81.3(148/182)**
- Live birth index (%)^5	96.0 (168/175)	96.9(157/162)	88.8(151/170)*	91.9(148/161)
- Sex ratio^6	83/168	80/157	83/151	75/148
- Sex ratio per dam (Mean ± SD)	0.50 ± 0.15	0.51 ± 0.12	0.54 ± 0.15	0.51 ± 0.15
- Preimplantation loss (%)^7	1.1 (2/183)	2.6 (5/191)	3.2 (6/188)	3.2 (6/188)
- Postimplantation loss^8 (%)	7.2 (13/181)	15.6 (29/186)*	17.0 (31/182)**	18.7 (34/182)**
- Pups weight (Mean ± SD, g)
Male	6.4 ± 0.5	6.6 ± 0.5	6.6 ± 0.6	6.5 ± 0.7
Female	6.2 ± 0.5	6.3 ± 0.5	6.0 ± 0.6	6.3 ± 0.7
Postnatal day 4
- Number of live pups (Mean ± SD)	13.7 ± 1.8	14.0 ± 2.1	13.4 ± 2.1	11.8 ± 3.0
- Number of live males (Mean ± SD)	6.5 ± 1.9	7.1 ± 1.9	7.8 ± 2.5	5.9 ± 2.2
- Number of live females (Mean ± SD)	6.7 ± 3.1	7.0 ± 2.1	4.3 ± 3.0	5.4 ± 2.8
- Viability index (%)^9	89.9 (151/168)	98.1 (154/157)**	80.1 (121/151)*	87.8 (130/148)
- Sex ratio^10	71/151	78/154	70/121	65/130
- Sex ratio per dam (Mean ± SD)	0.48 ± 0.13	0.51 ± 0.12	0.57 ± 0.13	0.57 ± 0.13
- Pups weight (Mean ± SD, g)
Male	9.6 ± 1.7	10.3 ± 1.3	9.8 ± 2.1	11.0 ± 1.2
Female	9.3 ± 1.6	9.9 ± 1.2	9.1 ± 2.1	10.5 ± 1.6

¹ Number of pregnant females with live pups / Number of pregnant females ×100

² Number of implantation sites / Number of corpora lutea × 100

³ Number of pups born / Number of implantation sites × 100

⁴ Number of live pups on postnatal day 0 / Number of implantation sites × 100

⁵ Number of live pups on postnatal day 0 / Number of pups born × 100

⁶ Number of live males on postnatal day 0 / Number of live pups on postnatal day 0

⁷ Number corpora lutea - Number of implantation sites) / Number of corpora lutea × 100

⁸ (Number of implantation sites - Number of live pups on postnatal day 0) / Number of implantation sites × 100

⁹ Number of live pups on postnatal day 4 / Number of live pups on postnatal day 0 × 100

¹⁰ Number of live males on postnatal day 4 / Number of live pups on postnatal day 4

* 　Significantly different from vehicle control at p <0.05

** Significantly different from vehicle control at p <0.01

Applicant's summary and conclusion

Conclusions:

Following the oral (gavage) administration of Bis(2-chloroethyl) ether at doses of 0.6, 3 and 15 mg/kg/Day, the only effect observed was a higher absolute and relative weights of the adrenal glands in the 15 mg/kg group of the male recovery group, and high absolute weights of the thymus in the same female group. However, as these findings were not associated with any other organic changes, they were considered incidental.
The No Observed Adverse Effect Level (NOAEL) for parental toxicity is therefore 15 mg/kg/Day.

There were no test item-related pathological changes in the male or female genital system and no effect on the oestrus cycle. here was no effect on gestation length, the number of corpora lutea or the number of implantation sites. No differences were observed on the gestation index, on the implantation index or on preimplantation loss. A lower delivery index was observed in test animals treated with 0.6 and 15 mg/kg bw/day. However, no effect was observed at 3 mg/kg bw/day and the connection with dose is thus unclear. The effect on delivery rate was considered incidental in the 0.6 and 3 mg/kg bw/day, while it was considered to be an effect of toxicity of the test substance at 15 mg/ kg bw/day.

Higher post-implantation loss was observed at 0.6 mg/kg bw/day and above (7.2, 15.6, 17.0 and 18.7%, in the control, 0.6, 3, 15 mg/kg bw/day group, respectively). Similarly, lower birth index (Number of live pups on postnatal day 0 / Number of implantation sites × 100) was observed at 0.6 mg/kg bw/day and above (92.8, 84.4, 83.0 and 81.3%, in the control, 0.6, 3, 15 mg/kg bw/day group, respectively).

Under the conditions of this study he No Observed Adverse Effect Level (NOAEL) for P0 reproductive performance is 3 mg/kg/day based on reduced delivery index at 15 mg/kg bw/day. The NOEL for P0 reproductive performance and foetal toxicity is < 0.6 mg/kg/day based slighlty higher post-implantation loss and lower birth index at 0.6 mg/kg bw/day.

Executive summary:

The objectives of this study, conducted on behalf of the Japanese Ministry of Health, Labour and Welfare, were to evaluate the potential toxic effects of the test item, Bis(2-chloroethyl) ether, when exposed for a minimum of 28 Days and the potential to affect male and female reproductive performance such as gonadal function, mating behaviour, conception, parturition and early postnatal development. Parental, reproduction (up to and including implantation) and developmental (from implantation onwards) No-Observed-Adverse-Effect-Levels (NOAELs) were evaluated. This GLP study was carried out according to OECD test guideline No. 422.

Three groups of 12 males and 12 femalesCrl:CD (SD) rats were given the test item, Bis(2-chloroethyl) ether, by daily oral (gavage) administration at dose levels of 0.6, 3 and 15 mg/kg/day. The male animals received dosing starting two weeks prior to the start of the mating period, throughout the mating period, and up to the day before the necropsy, for a total of 42 days. The female animals received dosing starting two weeks prior to the start of the mating period, throughout the mating, gestation, and nursing periods, and up to the day before the necropsy (fourth day of delivery), for a total of 42 to 45 days. Males and females were subjected to general and detailed observation throughout dosing, including functional assessments, weight and food intake measurements, necropsy, histopathological examinations of major organs and blood tests.

High absolute and relative weights of the adrenal glands were seen in the 15 mg/kg group of the male recovery group, and high absolute weights of the thymus were seen in the same female group. However, the adrenal glands did not have any other accompanying organic changes, nor were any changes seen in the relative weights of the thymus, so these were judged to be incidental changes. No ignificant change in any other the investigated parameters was observed at 15 mg/kg bw/day, which was considered to be the No Observed Adverse Effect Level (NOAEL) for parental toxicity.

P0 Generation:

There were no test item-related pathological changes in the male or female genital system and no effect on the oestrus cycle. All females were pregnant in the control and treated groups. There was no effect on gestation length, the number of corpora lutea or the number of implantation sites. No differences were observed on the gestation index, on the implantation index or on preimplantation loss. A lower delivery index was observed in test animals treated with 0.6 and 15 mg/kg bw/day. However, no effect was observed at 3 mg/kg bw/day and the connection with dose is thus unclear. The effect on delivery rate was considered incidental in the 0.6 and 3 mg/kg bw/day, while it was considered to be an effect of toxicity of the test substance at 15 mg/ kg bw/day.

Higher post-implantation loss was observed at 0.6 mg/kg bw/day and above (7.2, 15.6, 17.0 and 18.7%, in the control, 0.6, 3, 15 mg/kg bw/day group, respectively). Similarly, lower birth index (Number of live pups on postnatal day 0 / Number of implantation sites × 100) was observed at 0.6 mg/kg bw/day and above (92.8, 84.4, 83.0 and 81.3%, in the control, 0.6, 3, 15 mg/kg bw/day group, respectively). However, it is unclear if these observations originate from toxicity towards germ cells of the P0 generation, from embryotoxicity or, more generally, from maternal toxicity. In addition, no effect was observed on measured parameters and significant differences were only observed on derived indices.

F1 generation:

The live birth index (number of pups born alive/number of pups born x 100) was slightly lower in the 3 mg/kg bw/day (88.8%) compared with the concurrent contrl (96%). However, without any dose relationship and any similar finding at the high dose of 15 mg/kg bw/day, this was considered incidental.

Higher (98.1%) day 4 survival rates (i.e. viability index corresponding to the number of pups alive on PND 4/number of pups born alive x 100) as compared to control (89.9%) was observed in the 0.6 mg/kg bw/day group. At the opposite, a significant decrease in the viability index was found in the 3 mg/kg group (80.1%), while no significant effects were detected at 15 mg/kg bw/day (87.8%). Without any dose relationship and without any significant effect observed at 15 mg/kg bw/day, these observations were considered as incidental.

In conclusion, under the conditions of this study the No Observed Adverse Effect Level (NOAEL) for P0 reproductive performance is 3 mg/kg/day based on reduced delivery index at 15 mg/kg bw/day. The NOEL for P0 reproductive performance and fetal toxicity is < 0.6 mg/kg/day based slightly higher post-implantation loss and lower birth index at 0.6 mg/kg bw/day.