1,2-Benzenediol, 4-[(4-methylphenyl)sulfonyl]-

Endpoint summary

Description of key information

An OECD 422 study for a structural analogue showed no effects at the highest tested dose (750 mg/kg bw). Therefore, the NOAEL for CH04008 was set at 750 mg/kg.

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

experimental study

Adequacy of study:

key study

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)

Principles of method if other than guideline:

/

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

A total of ninety six animals (forty eight males and forty eight females) were accepted into the study. At the start of treatment the males weighed 316 to 360g, the females weighed 196 to 227g, and were approximately twelve weeks old.
The animals were acclimatized for six days during which time their health status was assessed.
Initially, all animals were housed in groups of three in solid floor polypropylene cages with stainless steel mesh lids and softwood flake bedding (Datesand Ltd., Cheshire, UK). During the pairing phase, animals were transferred to polypropylene grid floor cages suspended over trays lined with absorbent paper on a one male: one female basis within each dose group. Following evidence of successful mating, the males were returned to their original cages. Mated females were housed individually during gestation and lactation in solid floor polypropylene cages with stainless steel mesh lids and softwood flakes.
The animals were allowed free access to food and water. A pelleted diet (Rodent 2018C Teklad Global Certified Diet, Harlan Laboratories U.K. Ltd., Oxon, UK.) was used. Certificates of analysis of the batches of diet used are given in Appendix 28. Mains drinking water was supplied from polycarbonate bottles attached to the cage. Environmental enrichment was provided in the form of wooden chew blocks and cardboard fun tunnels (Datesand Ltd., Cheshire, UK) except for paired animals and mated females during gestation and lactation. Mated females were also given softwood flakes, as bedding, throughout gestation and lactation. The diet, drinking water, bedding and environmental enrichment was considered not to contain any contaminant at a level that might have affected the purpose or integrity of the study.
The animals were housed in a single air-conditioned room within the Harlan Laboratories Ltd., Shardlow, UK Barrier Maintained Rodent Facility. The rate of air exchange was at least fifteen air changes per hour and the low intensity fluorescent lighting was controlled to give twelve hours continuous light and twelve hours darkness. Environmental conditions were continuously monitored by a computerized system, and print-outs of hourly temperatures and humidities are included in the study records. The Study Plan target ranges for temperature and relative humidity were 22 ± 3 °C and 50 ± 20% respectively; short term deviations from these targets were considered not to have affected the purpose or integrity of the study; see deviations from Study Plan.
The animals were randomly allocated to treatment groups using a stratified body weight randomization procedure and the group mean body weights were then determined to ensure similarity between the treatment groups. The cage distribution within the holding rack was also
randomized. The animals were uniquely identified within the study by an ear punching system routinely used in these laboratories.

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

The test item was administered daily by gavage using a stainless steel cannula attached to a disposable plastic syringe.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples of the test item formulation were taken and analyzed for concentration of CH03951/BK at Harlan Laboratories Ltd., Shardlow, UK, Analytical Services. The test item concentration in the test samples was determined by HPLC with UV detection using an external standard technique. The results indicate that the prepared formulations were within ± 10% of the nominal concentration.

Duration of treatment / exposure:

Groups of twelve male and twelve female animals were treated daily at the appropriate dose level throughout the study (except for females during parturition where applicable). The first day of dosing was designated as Day 1 of the study.

Frequency of treatment:

Daily

Remarks:

Doses / Concentrations:
100 mg/kg bw
Basis:
other: nominal

Remarks:

Doses / Concentrations:
300 mg/kg bw
Basis:
other: nominal

Remarks:

Doses / Concentrations:
750 mg/kg bw
Basis:
other: nominal

No. of animals per sex per dose:

12 animals per sex per dose ( 3 doses and control: 96 in total)

Control animals:

yes

Positive control:

Not present

Observations and examinations performed and frequency:

Adult Responses Mortality
At 750 mg/kg bw/day, one female was killed in extremis due to a deterioration in physical condition considered to be associated with parturition/early lactation.
There were no further unscheduled deaths.
Clinical Observations
Clinical signs were confined to increased post dosing salivation for both sexes at 750 and 300 mg/kg bw/day; this was considered not related to the toxicity of the test item.
No such effects were observed in animals of either sex receiving 100 mg/kg bw/day.
Behavioral Assessment
No treatment-related effects were detected in animals treated with 750, 300 or 100 mg/kg bw/day.
Functional Performance Tests
There were no treatment-related changes in functional performance of animals receiving 750, 300 or 100 mg/kg bw/day.
Sensory Reactivity Assessments
There were no treatment-related changes in sensory reactivity of animals receiving 750, 300 or 100 mg/kg bw/day.
Body Weight
During the first two weeks of treatment, 750 mg/kg bw/day group males showed a slight reduction in body weight gains with improvement evident thereafter. No effects on body weight development were detected in males from the remaining test groups or in any of the female test groups throughout the treatment period.
Food Consumption
There were no adverse effects on food consumption or food efficiency for males during the study or for females during the pre-pairing, gestation or lactation phases of the study.
Water Consumption
Females treated with 750 mg/kg bw/day showed a slight increase (+ 23%) in water intake when compared to controls. No such effects were detected in males treated with 750 mg/kg bw/day or in animals of either sex treated with 300 or 100 mg/kg bw/day.
Reproductive Performance Mating No treatment-related effects were detected in mating performance.
Fertility
There were no treatment-related differences in fertility.
Gestation Lengths
There were no differences in gestation lengths. The distribution for all treated females was compared to controls. Gestation lengths were between 22 and 231⁄2 days.
Litter Responses Offspring Litter Size, Sex Ratio and Viability
Of the litters born, litter size at birth and subsequently on Days 1 and 4 post partum were comparable to controls. Sex ratio in treated litters was comparable to controls.
Offspring Growth and Development
Offspring body weight gain and litter weights at birth and subsequently on Days 1 and 4 post partum were considered to be unaffected by treatment. Surface righting reflex in treated litters was comparable to controls.
The clinical signs and necropsy findings apparent for offspring on the study were typical for the age observed.
Laboratory Investigations
Hematology
There were no toxicological significant changes detected in the hematological parameters examined.
Blood Chemistry
There were no toxicological significant changes detected in the blood chemical parameters examined.
Pathology Necropsy There were no treatment-related macroscopic abnormalities detected.
Organ Weights
No toxicologically significant changes were detected in the organ weights measured.
Histopathology
There was no evidence of treatment-related histopathological changes in the organs and tissues examined.

Sacrifice and pathology:

Necropsy There were no treatment-related macroscopic abnormalities detected.
Organ Weights
No toxicologically significant changes were detected in the organ weights measured.
Histopathology
There was no evidence of treatment-related histopathological changes in the organs and tissues examined.

Statistics:

Statistical analysis was performed on the following parameters:
Grip Strength, Motor Activity, Body Weight, Body Weight Change, Food Consumption during gestation and lactation, Pre-Coital Interval, Gestation Length, Litter Size, Litter Weight, Sex Ratio, Corpora Lutea, Implantation Sites, Implantation Losses, Viability Indices, Offspring Body Weight, Offspring Body Weight Change, Offspring Surface Righting, Hematology, Blood Chemistry, Absolute Organ Weights, Body Weight-Relative Organ Weights.

Data were analyzed using the decision tree from the ProvantisTM Tables and Statistics Module.

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Clinical signs were confined to increased post dosing salivation for both sexes at 750 and 300 mg/kg bw/day; this was considered not related to the toxicity of the test item. No such effects were observed in animals of either sex receiving 100 mg/kg bw/da

Mortality:

mortality observed, non-treatment-related

Description (incidence):

At 750 mg/kg bw/day, one female was killed in extremis due to a deterioration in physical condition considered to be associated with parturition/early lactation.
There were no further unscheduled deaths.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

During the first two weeks of treatment, 750 mg/kg bw/day group males showed a slight reduction in body weight gains with improvement evident thereafter. No effects on body weight development were detected in males from the remaining test groups or in any of the female test groups throughout the treatment period.

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

no effects observed

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

no effects observed

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Details on results:

The oral administration of CH03951/BK to rats by gavage, at dose levels of 100, 300 and 750 mg/kg bw/day was well tolerated.

Dose descriptor:

NOEL

Effect level:

750 mg/kg bw/day (nominal)

Based on:

not specified

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical signs

mortality

Critical effects observed:

not specified

Conclusions:

The oral administration of CH03951/BK to rats by gavage, at dose levels of 100, 300 and 750 mg/kg bw/day was well tolerated. Based on the available results, the ‘No Observed Adverse Effect Level’ (NOAEL) for systemic toxicity was considered to be 750 mg/kg bw/day.
The ‘No Observed Effect Level’ (NOEL) for reproductive toxicity was considered to be 750 mg/kg bw/day.

Executive summary:

SUMMARY

Introduction

The study was designed to investigate the systemic toxicity and potential adverse effects of the test item on reproduction (including offspring development) and is designed to be compatible with the requirements of the OECD Guidelines for Testing of Chemicals No. 422 “Combined Repeated Dose Toxicity Study with the Reproduction/ Developmental Toxicity Screening Test” (adopted 22 March 1996).

This study was also designed to be compatible with Commission Regulation (EC) No 440/2008 of 30 May 2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH).

Methods.......

The test item was administered by gavage to three groups, each of twelve male and twelve female Wistar HanTM:RccHanTM:WIST strain rats, for up to eight weeks (including a two week pre-pairing phase, pairing, gestation and early lactation for females), at dose levels of 100, 300 and 750 mg/kg bw/day. A control group of twelve males and twelve females was dosed with vehicle alone (Arachis oil BP).

Clinical signs, behavioral assessments, body weight change and food and water consumption were monitored during the study.

Pairing of animals within each dose group was undertaken on a one male: one female basis within each treatment group on Day 15 of the study, with females subsequently being allowed to litter and rear their offspring to Day 5 of lactation.

During the lactation phase, daily clinical observations were performed on all surviving offspring, together with litter size and offspring weights and assessment of surface righting reflex.

Extensive functional observations were performed on five selected males from each dose group after the completion of the pairing phase, and for five selected parental females from each dose group on Day 4 post partum. Hematology and blood chemistry were evaluated prior to termination on five selected males and females from each dose group.

Adult males were terminated on Day 43 or 44, followed by the termination of all surviving females and offspring on Day 5 post partum. Any female which did not produce a pregnancy was terminated on or after Day 25 post coitum. All animals were subjected to a gross necropsy examination and histopathological evaluation of selected tissues was performed.

Results.......

Adult Responses

Mortality

At 750 mg/kg bw/day, one female was killedin extremisdue to a deterioration in physical condition considered to be associated with parturition/early lactation.

There were no further unscheduled deaths.

Clinical Observations

Clinical signs were confined to increased post dosing salivation for both sexes at 750 and 300 mg/kg bw/day; this was considered not related to the toxicity of the test item.

No such effects were observed in animals of either sex receiving 100 mg/kg bw/day.

Behavioral Assessment

No treatment-related effects were detected in animals treated with 750, 300 or 100 mg/kg bw/day.

Functional Performance Tests

There were no treatment-related changes in functional performance of animals receiving 750, 300 or 100 mg/kg bw/day.

Sensory Reactivity Assessments

There were no treatment-related changes in sensory reactivity of animals receiving 750, 300 or 100 mg/kg bw/day.

Body Weight

During the first two weeks of treatment, 750 mg/kg bw/day group males showed a slight reduction in body weight gains with improvement evident thereafter. No effects on body weight development were detected in males from the remaining test groups or in any of the female test groups throughout the treatment period.

Food Consumption

There were no adverse effects on food consumption or food efficiency for males during the study or for females during the pre-pairing, gestation or lactation phases of the study.

Water Consumption

Females treated with 750 mg/kg bw/day showed a slight increase (+ 23%) in water intake when compared to controls. No such effects were detected in males treated with 750 mg/kg bw/day or in animals of either sex treated with 300 or 100 mg/kg bw/day.

Reproductive Performance
Mating
No treatment-related effects were detected in mating performance.

Fertility

There were no treatment-related differences in fertility.

Gestation Lengths

There were no differences in gestation lengths. The distribution for all treated females was compared to controls. Gestation lengths were between 22 and 231⁄2 days.

Litter Responses
Offspring Litter Size, Sex Ratio and Viability

Of the litters born, litter size at birth and subsequently on Days 1 and 4post partumwere comparable to controls. Sex ratio in treated litters was comparable to controls.

Offspring Growth and Development

Offspring body weight gain and litter weights at birth and subsequently on Days 1 and 4post partumwere considered to be unaffected by treatment. Surface righting reflex in treated litters was comparable to controls.

The clinical signs and necropsy findings apparent for offspring on the study were typical for the age observed.

Laboratory Investigations

Hematology

There were no toxicological significant changes detected in the hematological parameters examined.

Blood Chemistry

There were no toxicological significant changes detected in the blood chemical parameters examined.

Pathology
Necropsy
There were no treatment-related macroscopic abnormalities detected.

Organ Weights

No toxicologically significant changes were detected in the organ weights measured.

Histopathology

There was no evidence of treatment-related histopathological changes in the organs and tissues examined.

Conclusion

The oral administration of CH03951/BK to rats by gavage, at dose levels of 100, 300 and 750 mg/kg bw/day was well tolerated. Based on the available results, the ‘No Observed Adverse Effect Level’ (NOAEL) for systemic toxicity was considered to be 750 mg/kg bw/day.

The ‘No Observed Effect Level’ (NOEL) for reproductive toxicity was considered to be 750 mg/kg bw/day.

Reference 2

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

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

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
[Please provide information for all of the points below. Indicate if further information is included as attachment to the same record, or elsewhere in the dataset (insert links in 'Cross-reference' table)]

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
[Describe why the read-across can be performed (e.g. common functional group(s), common precursor(s)/breakdown product(s) or common mechanism(s) of action]

See attached documents.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
[Provide here, if relevant, additional information to that included in the Test material section of the source and target records]
See attached documents.


3. ANALOGUE APPROACH JUSTIFICATION
[Summarise here based on available experimental data how these results verify that the read-across is justified]
See attached documents.

4. DATA MATRIX
See attached documents.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

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

Principles of method if other than guideline:

/

GLP compliance:

yes

Limit test:

no

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

Clinical signs were confined to increased post dosing salivation for both sexes at 750 and 300 mg/kg bw/day; this was considered not related to the toxicity of the test item. No such effects were observed in animals of either sex receiving 100 mg/kg bw/da

Mortality:

mortality observed, non-treatment-related

Description (incidence):

At 750 mg/kg bw/day, one female was killed in extremis due to a deterioration in physical condition considered to be associated with parturition/early lactation.
There were no further unscheduled deaths.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

During the first two weeks of treatment, 750 mg/kg bw/day group males showed a slight reduction in body weight gains with improvement evident thereafter. No effects on body weight development were detected in males from the remaining test groups or in any of the female test groups throughout the treatment period.

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

no effects observed

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

no effects observed

Ophthalmological findings:

not specified

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Neuropathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Details on results:

The oral administration of CH03951/BK to rats by gavage, at dose levels of 100, 300 and 750 mg/kg bw/day was well tolerated.

Dose descriptor:

NOEL

Effect level:

750 mg/kg bw/day (nominal)

Based on:

not specified

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical signs

mortality

Critical effects observed:

not specified

Conclusions:

No effects were observed in the OECD 422 study for a structural analogue (CH03951).
Therefore, the NOAEL for CH04008 was set at 750 mg/kgbw.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

750 mg/kg bw/day

Study duration:

subacute

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available