Bis(4-chlorophenyl) sulphone

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Valid guideline study under GLP-conditions.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Bis(4-chlorophenyl) sulphone

EC Number:

201-247-9

EC Name:

Bis(4-chlorophenyl) sulphone

Cas Number:

80-07-9

Molecular formula:

C12H8Cl2O2S

IUPAC Name:

1-chloro-4-(4-chlorobenzenesulfonyl)benzene

Details on test material:

- Name of test material: 4,4'-dichlorodiphenyl sulfone
- Physical state: white solid pellets
- Analytical purity: >98.4 %
- Batch No.: LP070811
- Storage condition: at room temperature in the dark

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Limited, Margate, Kent, UK
- Age at study initiation: approximately 8 weeks old
- Weight at study initiation: 286-361 g (males), 192-233 g (females)
- Housing: in solid floor polypropylene cages with stainless steel grid tops and softwood flake bedding (Datesand Ltd, Cheshire, UK); in groups of 5 animals/sex/cage premating, or 1 male and 1 female/cage during the mating period, or 1 mated female/cage during gestation and lactation
- Diet: pelleted diet (Rodent PMI 5002 certified diet, BCM IPS Limited, London, UK), ad libitum
- Water: mains drinking water supplied from polycarbonate bottles, ad libitum
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature: 21 ± 2 °C
- Humidity: 55 ± 15 %
- Air changes: 15 air changes/hour
- Photoperiod: 12 hours dark / 12 hours light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on exposure:

PREPARATION OF DOSING SOLUTIONS
The test material was prepared at the appropriate concentrations as a suspension in Arachis oil BP. The stability and homogeneity of the dose formulations were determined. Formulations were shown to be stable for at least 14 days. Samples were taken of each formulation and analysed for DCDPS concentration.

VEHICLE
- Justification for use and choice of vehicle: Arachis oil BP is a standard vehicle in studies of this type
- Concentration in vehicle: 0, 1.25, 3.75 or 12.5 mg/mL
- Amount of vehicle: a dose volume of 4 mL/kg bw was used

Details on mating procedure:

- M/F ratio per cage: 1:1 within each dose group
- Length of cohabitation: max. 14 days
- Proof of pregnancy: vaginal plug and sperm in vaginal smear referred to as day 0 of pregnancy

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentration of DCDPS in the test material formulations was determined by high performance liquid chromatography (HPLC) using an external standard technique. The test material formulations were extracted with acetonitrile to give a final, theoretical test material concentration of approximately 0.1 mg/mL. Standard solutions of test material were prepared in acetonitrile at a nominal concentration of 0.1 mg/mL. The standard and sample solutions were then analysed by HPLC. The analytical method has been satisfactorily validated in terms of linearity, specificity and accuracy for the purposes of the study.

Duration of treatment / exposure:

42 days
Total observation time up to 54 consecutive days (including a two week maturation phase, pairing, gestation and early lactation for females)

Frequency of treatment:

once daily

Details on study schedule:

- Age at mating of the mated animals in the study: approximately 10 weeks

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 5, 15, and 50 mg/kg bw/day
Basis:
actual ingested

No. of animals per sex per dose:

10 animals

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on previous toxicology studies

Positive control:

none

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS:
- Time schedule: before dosing and up to 5 hours (workdays) or 1 hour (weekend) thereafter

BODY WEIGHT:
- Time schedule for examinations: day 1, weekly thereafter (males); weekly until mating, GD 0, 7, 14, 20, PPD 1 and 4

FOOD CONSUMPTION :
- Food consumption for each group determined and mean daily diet consumption calculated as g food/rat/day: Yes, premating and 3 weeks after and individual for females during pregnancy.

FEED EFFICIENCY:
Body weight gain/feed intake: for periods of measured feed consumption

WATER CONSUMPTION:
Visual observation only

Oestrous cyclicity (parental animals):

A vaginal smear was prepared for each female and the stage of the oestrous cycle was recorded.

Sperm parameters (parental animals):

Parameters examined in the male parental generation:
testis weight, epididymis weight

Litter observations:

All live offspring were assessed for surface righting reflex on day 1 post partum

Postmortem examinations (parental animals):

Full external and internal examination for macroscopic anomalies.
Organ weights: epididymes, testes, liver
Histopathology: coagulation gland, liver, ovaries, pituitary, prostate, seminal vesicles, testes, uterus/cervix, vagina

Postmortem examinations (offspring):

Full external and internal examination for macroscopic anomalies

Statistics:

Standard methods such as linear regression, ANOVA, Dunntett's, Mann Whitney U test for parametric values, Chi square and Kruskall Wallis for non parametric data.

Reproductive indices:

All parameters as given in OECD TGD 421, i.e. pre-coital interval, mating Index, preganancy index, gestation length, parturition index, percent pre-implantation loss, percent post-implantation loss

Offspring viability indices:

All parameters as given in OECD TGD 421, i.e. live birth index, viability index, sex ratio plus weights and righting reflex on day 4.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Other effects:

no effects observed

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

Details on results (P0)

GENERAL REMARK (PARENTAL ANIMALS AND OFFSPRING)
Relevant data are summarised in tabular form in section "Any other information on results incl. tables"

MORTALITY AND CLINICAL OBSERVATIONS (PARENTAL ANIMALS)
One female treated with 15 mg/kg bw/day was killed in extremis due to a physical injury to the right ear. There were no further unscheduled deaths. No clinical signs of toxicity were noted.

BODY WEIGHT (PARENTAL ANIMALS)
Males treated with 50 mg/kg bw/day showed a reduction in cumulative body weight gain throughout the treatment period and a reduction in weekly body weight gain during the first two weeks of treatment. Sligthly lower weight gains (not reaching statistical significance) were also observed in the high dose females during the premating phase. No such effects were detected in animals of either sex treated with 15 or 5 mg/kg bw/day.

TEST SUBSTANCE INTAKE (PARENTAL ANIMALS)
No adverse effect on dietary intake or food efficiency was detected.

REPRODUCTIVE FUNCTION AND PERFORMANCE (PARENTAL ANIMALS)
There was no adverse effect detected on mating or fertility. Gestation or parturition indices were not affected by the treatment with the test item.

GROSS PATHOLOGY
Enlarged livers were noted in 10/10 males and 7/10 females treated with 50 mg/kg bw/day. Liver enlargement was also seen in 8/10 males at 15 mg/kg bw/day.

ORGAN WEIGHTS
Animals of either sex from all treatment groups showed a dose related and statisitically significant increase in liver weights, both absolute and relative to terminal body weight. The increased relative epididymides and testes weights were not considered as toxicologically relevant in the absence of histological correlates.

HISTOPATHOLOGY
Centrilobular hepatocyte enlargement was seen for all animals examined of either sex in all treated groups. The incidence of the condition was statistically significant for all treatment groups. There was also a dose response for either sex in terms of the incidence of severity grades (males were more sensitive). Centrilobular hepatocyte vacuolation was also seen among mid and high dose animals, being more prevalent and statistically significant for high dose males only.

Effect levels (P0)

1

Dose descriptor:

NOAEL

Remarks:

for adult toxicity

Effect level:

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

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Centrilobular hypertrophy at 50 mg/kg bw/day associated with vacuolation.

2

Dose descriptor:

NOAEL

Remarks:

for adult toxicity

Effect level:

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

Based on:

test mat.

Sex:

female

Basis for effect level:

other: There was no clear significance for adverse histopathology up to and including the high dose level.

3

Dose descriptor:

NOAEL

Remarks:

toxicity to reproduction/fertility

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: There were no effects on reproductive perfomance up to and including the high dose level.

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Details on results (F1)

VIABILITY (OFFSPRING)
No treatment related effects were detected.

CLINICAL SIGNS (OFFSPRING)
There were no treatment related clinical findings from birth to day 5 post partum.

BODY WEIGHT (OFFSPRING)
Mean offspring body weight gain between days 1 and 4 of lactation were statistically significantly reduced for offspring from litters treated with 50 mg/kg bw/day. No such effects were detected in offspring from litters treated with 15 or 5 mg/kg bw/day.

GROSS PATHOLOGY (OFFSPRING)
Neither the incidence, type or distribution of macroscopic findings observed at necropsy of decedent offspring nor offspring killed at scheduled termination (day 5 of age) indicated any adverse effect of maternal treatment.

OTHER FINDINGS (OFFSPRING)
The percentage of offspring who successfully showed surface righting reflex on day 1 and the type, incidence and distribution of clinical signs in the offspring to termination on day 5 of age was unaffected by maternal exposure.

Effect levels (F1)

Dose descriptor:

other:

Generation:

F1

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Remarks on result:

other: The observed reduction of offspring growth (developmental effect) was distinct but likely to be secondary to the maternal effects, but this can not be finally assessed based on the available data.

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Body weight and body weight change for male parents

Dose level [mg/kg bw/day]

Body weight [g] at day

1

8

15

22

29

36

43

0 (control)

324 ± 16

363 ± 20

387 ± 22

407 ± 27

435 ± 27

459 ± 28

467 ± 32

5

326 ± 17

361 ± 26

383 ± 32

407 ± 35

433 ± 37

453 ± 42

463 ± 44

15

332 ± 18

368 ± 31

389 ± 41

410 ± 44

440 ± 49

459 ± 50

475 ± 48

50

327 ± 15

350 ± 25

361 ± 28

376 ± 26

397 ± 31

420 ± 30

428 ± 34

Dose level [mg/kg bw/day]

Cumulative body weight change [g] relative to day 1 in week

1

2

3

4

5

6

0 (control)

39 ± 09

64 ± 10

83 ± 16

111 ± 17

135 ± 17

144 ± 22

5

35 ± 11

57 ± 18

81 ± 23

107 ± 24

127 ± 29

137 ± 32

15

37 ± 17

57 ± 28

78 ± 30

108 ± 38

128 ± 38

143 ± 35

50

23 ± 12 *

34 ± 17 **

49 ± 19 **

70 ± 26 **

93 ± 24 **

101 ± 28 **

All values are mean ± standard deviation of 10 animals

* Significantly different from control group p<0.05

** Significantly different from control group p<0.01

 

Body weight and body weight change for female parents

Dose level [mg/kg bw/day]

Body weight [g] at day

Maturation

Gestation

Lactation

1

8

15

0

7

14

20

1

4

0 (control)

213 ± 12

223 ± 12

231 ± 20

239 ± 13

273 ± 15

310 ± 15

387 ± 25

292 ± 20

306 ± 23

5

219 ± 10

228 ± 11

239 ± 13

244 ± 10

278 ± 14

313 ± 14

393 ± 23

293 ± 22

311 ± 18

15

213 ± 10

218 ± 12

227 ± 16

234 ± 9

272 ± 14

306 ± 15

386 ± 20

283 ± 18

304 ± 15

50

213 ± 9

216 ± 8

219 ± 12

227 ± 11

262 ± 15

298 ± 17

374 ± 22

276 ± 17

297 ± 21

Dose level [mg/kg bw/day]

Cumulative body weight change [g] relative to day 1 in week

Maturation

Gestation

Lactation

Week 1

Week 2

Day 0-7

Day 7-14

Day 14-20

Days 1-4

0 (control)

10 ± 5

18 ± 12

34 ± 8

72 ± 8

148 ± 16

15 ± 10

5

9 ± 9

21 ± 11

34 ± 7

69 ± 8

149 ± 17

18 ± 10

15

5 ± 8

14 ± 14

38 ± 6

72 ± 7

153 ± 13

21 ± 9

50

3 ± 6

7 ± 10

35 ± 8

71 ± 12

148 ± 18

21 ± 8

All values are mean ± standard deviation of 10 animals except in the 15 mg/kg bw/day, where from gestation day 0 only 9 animals were counted due to sacrification of one female.

 

Offspring body weight and body weight change

Dose level [mg/kg bw/day]	Offspring body weight [g]				Offspring body weight change [g]
	Day 1		Day 4		Days 1-4
	Males	Females	Males	Females	Males	Females
0 (control)	7.3 ± 0.9	6.8 ± 0.8	10.5 ± 1.5	9.9 ± 1.5	3.2 ± 0.7	3.1±0.8
5	6.8 ± 0.6	6.4 ± 0.6	9.7 ± 1.3	9.0 ± 1.2	2.9±0.8	2.6±0.7
15	6.8 ± 0.6	6.6 ± 0.5	9.3 ± 0.9	8.9 ± 0.8	2.5±0.5	2.4±0.5
50	7.0 ± 0.7	6.6 ± 0.6	9.3 ± 1.3	8.7 ± 1.2	2.3±0.6 *	2.1±0.7 **

All values are mean ± standard deviation of 10 animals

* Significantly different from control group p<0.05

** Significantly different from control group p<0.01

 

Organ weights of male parents

Dose level [mg/kg bw/day]	Epididymis		Testes		Liver^a
0 (control)
Absolute [g]	1.3064	± 0.1098	3.3950	± 0.2470	16.4012	± 1.7257
Relative [%bw]	0.2800	± 0.0198	0.7283	± 0.0531	3.5047	± 0.1819
5
Absolute [g]	1.3386	± 0.1289	3.6080	± 0.2665	19.3653	± 2.4770**
Relative [%bw]	0.2898	± 0.0243	0.7836	± 0.0772	4.1678	± 0.2370***
15
Absolute [g]	1.3607	± 0.0874	3.6308	± 0.1731	24.7682	± 3.8263***
Relative [%bw]	0.2886	± 0.0260	0.7719	± 0.0832	5.2163	± 0.6115***
50
Absolute [g]	1.3649	± 0.1020	3.6698	± 0.2512	26.6187	± 2.6710***
Relative [%bw]	0.3202	± 0.0309**	0.8598	± 0.0635***	6.2178	± 0.3991***

All values are mean ± standard deviation of 10 animals

^a Relative liver weights were increased by 19%, 49% and 77% with increasing dose

** Significantly different from control group (p≤0.01)

*** Significantly different from control group (p≤0.001)

Liver weights of female parents

Dose level [mg/kg bw/day]	Liver weight
	Absolute [g]	Relative [%]
0 (control)	12.4936 ± 1.2942	4.0327 ± 0.2571
5	14.3538 ± 0.9536**	4.5806 ± 0.3056**
15	16.3069 ± 1.1555***	5.2461 ± 0.2861***
50	20.7629 ± 2.2841***	6.8772 ± 0.6932***

All values are mean ± standard deviation of 10 animals

** Significantly different from control group p<0.01

*** Significantly different from control group p<0.001

Applicant's summary and conclusion

Conclusions:

All doses induced effects in the parental generation, which were significantly adverse in male rats. No effects on reproduction/fertility were seen in this study. The observed reduction of offspring growth (developmental effect) was distinct but likely to be secondary to the maternal effects, but this can not be finally assessed based on the available data.

Executive summary:

In a reproduction/developmental toxicity screening study (Safepharm Ltd, 2008), DCDPS (>98.4 %) in arachis oil was administered to 10 Sprague-Dawley rats/sex/dose level by oral gavage (4 mL/kg bw) at dose levels of 0 (vehicle only), 5, 15 or 50 mg/kg bw/day. Rats were dosed with DCDPS for two weeks maturation, pairing and pregnancy up to day 4 post partum, thus a total of 42 days. In the reproductive screening part of the study, there were no treatment related effects noted on mortality, clinical aspects, food and water consumption as well as food efficiency, reproductive performance/fertility and offspring litter size and viability. Males treated with 50 mg/kg bw/day showed a reduction in cumulative body weight gain throughout the treatment period and a reduction in weekly body weight gain during the first two weeks of treatment. Offspring from litters treated with 50 mg/kg bw/day showed a reduction in body weight gain considered as developmental effect. At necropsy, enlarged livers were seen in males at 15 mg/kg bw/day and in males and females at 50 mg/kg bw/day. Animals of either sex from all treatment groups showed an increase in liver weight. Dose-dependent centrilobular hepatocyte enlargement was seen in all treated groups. Centrilobular hepatocyte vacuolation was noted at 50 mg/kg bw/day being more prevalent in males. Based on these results, the NOAEL for parental toxicity was established at 15 and 50 mg/kg bw/day for male and female animals, respectively. The NOAEL for toxicity to reproduction/fertility was set at 50 mg/kg bw/day since no reproductive toxicity was seen.

This screening study is acceptable and satisfies the requirement for test guideline OECD 421.