Nickel, 5-[2-(2-hydroxy-3,7-disulfo-1-naphthalenyl)diazenyl]-1H-1,2,4-triazole-3-carboxylate sodium complexes

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

other information

Study period:

The study was performed between 20 June 2011 and 07 December 2011. The in-life phase of the study was conducted between 12 July 2011 (first day of treatment) and 27 August 2011 (final necropsy).

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. The study report was conclusive, done to a valid guideline and the studywas conducted under GLP conditions.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: OECD Guidelines for Testing of Chemicals No. 421 “Reproduction/Developmental Toxicity Screening Test” (adopted 27 July 1995)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: 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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

S190700

IUPAC Name:

S190700

Details on test material:

Sponsor's identification: S190700
Description : Green crystalline solid with gold flecks
Purity : 89.8%
Batch number: RD3630
Date received: 25 May 2011
Storage conditions: in the dark, at approximately 4˚C over silica gel
Expiry date : 01 May 2012

Test animals

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

A sufficient number of male and female Wistar Han™:RccHan™:WIST strain rats were obtained from reputable supplier. On receipt the animals were examined for signs of ill-health or injury. The animals were acclimatised for thirteen days during which time their health status was assessed. A total of eighty animals (forty males and forty females) were accepted into the study. At the start of treatment the males weighed 300 to 364g, the females weighed 188 to 221g, and were approximately twelve weeks old.
Initially, all animals were housed in groups of five in solid floor polypropylene cages with stainless steel mesh lids and softwood flake bedding (obtained from reputable supplier). During the mating phase, the animals were transferred to polypropylene grid floor cages suspended over trays lined with absorbent paper on a one male: one female basis. 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 (obtained from reputable supplier) was used. Certificates of analysis of the batches of diet used are given in Addendum 1. Mains drinking water was supplied from polycarbonate bottles attached to the cage. The diet and drinking water were considered not to contain any contaminant at a level that might have affected the purpose or integrity of the study. Environmental enrichment was provided in the form of wooden chew blocks and cardboard fun tunnels except for mated females during gestation and lactation. Mated females were also given softwood flakes, as bedding, throughout gestation and lactation.
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 computerised system and print-outs of hourly mean temperatures and humidities are included in the study records. The temperatures and relative humidity controls were set to achieve target values of 21 ± 2°C and 55 ± 15% respectively. Short term deviations from these targets were considered not to affect the purpose or integrity of the study.
The animals were allocated to dose groups using a randomisation procedure based on stratified body weights and the group mean body weights were then determined to ensure similarity between the dose groups. The animals were uniquely identified within the study, by an ear punching system routinely used in these laboratories.

Administration / exposure

Route of administration:

oral: gavage

Type of inhalation exposure (if applicable):

other: Not applicable

Vehicle:

other: distilled water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
For the purpose of this study the test item was prepared at the appropriate concentrations as a solution in distilled water. The stability and homogeneity of the test item formulations were determined by Harlan Laboratories Ltd., Shardlow, UK, Analytical Services. Results showed the formulations to be stable for at least fourteen days. Formulations were therefore prepared weekly and stored at approximately 4ºC in the dark.
Samples of each test item formulation were taken and analysed for concentration of S190700 at Harlan Laboratories Ltd., Shardlow, UK, Analytical Services. The method used for analysis of formulations and the results obtained are given in the attached Chemistry Report. The results indicate that the prepared formulations were within the acceptable ranges for the purpose of this study.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentration of S190700 in the test item formulations was determined spectrophotometrically . For full details see attached Chemistry Report.

Details on mating procedure:

Animals were paired on a 1 male: 1 female basis within each dose group, for a period of up to fourteen days. Cage tray-liners were checked each morning for the presence of ejected copulation plugs and each female was examined for the presence of a copulation plug in the vagina. A vaginal smear was prepared for each female and the stage of oestrus or the presence of sperm was recorded. The presence of sperm within the vaginal smear and/or vaginal plug in situ was taken as positive evidence of mating (Day 0 of gestation) and the males were subsequently returned to their original holding cages (unless required for additional pairing). Mated females were housed individually during the period of gestation and lactation.

Duration of treatment / exposure:

42 consecutive days for males and up to 47 consecutive days for females

Frequency of treatment:

Daily

Duration of test:

42 consecutive days for males and up to 47 consecutive days for females

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
50 mg/kg bw/day AI (10 mg/ml AI)
Basis:
actual ingested

Doses / concentrations 2

Remarks:

Doses / Concentrations:
250 mg/kg bw/day AI (50 mg/ml AI)
Basis:
actual ingested

Doses / concentrations 3

Remarks:

Doses / Concentrations:
1000 mg/kg bw/day (200 mg/ml AI)
Basis:
actual ingested

No. of animals per sex per dose:

Control-10 males and 10 females 0mg/kg bw/day
Low-10 males and 10 females 50mg/kg bw/day
Intermediate-10 males and 10 females 250mg/kg bw/day
High-10 males and 10 females 1000mg/kg bw/day

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
The dose levels were chosen based on the results of previous toxicity work (Harlan Laboratories Ltd., Project Number 780/287)

- Rationale for animal assignment (if not random):
Random.

- Other:
The oral route was selected as the most appropriate route of exposure, based on physical properties of the test item, and the results of the study are believed to be of value in screening potential adverse effects on reproduction.

Examinations

Maternal examinations:

CLINICAL OBSERVATIONS
All animals were examined for overt signs of toxicity, ill-health and behavioural change.
Immediately before dosing, up to thirty minutes after dosing, and one and five hours after dosing, during the working week. Animals were observed immediately before dosing, soon after dosing, and one hour after dosing at weekends and public holidays (except for females during parturition where applicable).

BODY WEIGHT:
Individual body weights were recorded on Day 1 (prior to dosing) and then weekly for males until termination and weekly for females until mating was evident. Body weights were then recorded for females on Days 0, 7, 14 and 20 post coitum, and on Days 1 and 4 post partum. Normal range data for body weight changes in pregnant and lactating females are presented in attached Addendum 2.

FOOD CONSUMPTION:
During the maturation period, weekly food consumption was recorded for each cage of adults. This was continued for males after the mating phase. For females showing evidence of mating, food consumption was recorded for the periods covering Days 0-7, 7-14 and 14-20. For females with live litters, food consumption was recorded on Days 1 and 4 post partum. Weekly food consumptions were performed weekly for each cage of adults throughout the study period.
Normal range data for pregnant and lactating females are presented in attached Addendum 2.

FOOD EFFICIENCY:
Weekly food efficiency (body weight gain/food intake) was calculated retrospectively for males and for females during the pre-mating phase. Due to offspring growth and milk production, food efficiency could not be accurately calculated during gestation and lactation.
Normal range data for pregnant and lactating females are presented in attached Addendum 2.

WATER CONSUMPTION:
Water intake was observed daily by visual inspection of water bottles for any overt changes up to Day 9 of the study. From Day 10 of the study onwards water intake was measured gravimetrically.

REPRODUCTION PERFORMANCE
MATING:
Animals were paired on a 1 male: 1 female basis within each dose group, for a period of up to fourteen days. Cage tray-liners were checked each morning for the presence of ejected copulation plugs and each female was examined for the presence of a copulation plug in the vagina. A vaginal smear was prepared for each female and the stage of oestrus or the presence of sperm was recorded. The presence of sperm within the vaginal smear and/or vaginal plug in situ was taken as positive evidence of mating (Day 0 of gestation) and the males were subsequently returned to their original holding cages (unless required for additional pairing). Mated females were housed individually during the period of gestation and lactation.

PREGNANCY AND PARTURITION:
Each pregnant female was observed at approximately 0830, 1230 and 1630 hours and around the period of expected parturition. Observations were carried out at approximately 0830 and 1230 hours at weekends and public holidays. The following was recorded for each female:
i) Date of pairing
ii) Date of mating
iii) Date and time of observed start of parturition
iv) Date and time of observed completion of parturition

LITTER DATA:
On completion of parturition (Day 0 post partum), the number of live and dead offspring was recorded. Offspring were individually identified within each litter by tattoo on Day 1 post partum.
For each litter the following was recorded:
i) Number of offspring born
ii) Number of offspring alive recorded daily and reported on Days 1 and 4 post partum
iii) Sex of offspring on Days 1 and 4 post partum
iv) Clinical condition of offspring from birth to Day 5 post partum
v) Individual offspring weights on Days 1 and 4 post partum (litter weights were calculated retrospectively from this data)

PHYSICAL DEVELOPMENT:
All live offspring were assessed for surface righting reflex on Day 1 post partum.

PATHOLOGY:
POST-MORTEM EXAMINATIONS:
Male animals: Adult surviving males were killed by intravenous overdose of a suitable barbiturate agent followed by exsanguination on Day 43.
Maternal animals: Adult surviving females were killed by intravenous overdose of a suitable barbiturate agent followed by exsanguination on Day 5 post partum. Any females that failed to achieve pregnancy or produce a litter were killed on or after Day 26 post coitum.

Gross pathology: For all females, the uterus was examined for signs of implantation and the number of uterine implantations in each horn was recorded. This procedure was enhanced; as necessary, by staining the uteri with a 0.5% ammonium polysulphide solution. In addition, the corpora lutea of all ovaries from pregnant females were counted at necropsy. All adult animals, including those dying during the study, were subjected to a full external and internal examination, and any macroscopic abnormalities were recorded.

Histopathology/organ weights:
The epididymides and testes were removed from terminal kill adult males dissected free from fat and weighed before fixation.

Samples of the following tissues were preserved from five males and five females from each dose group, in buffered 10% formalin except epididymides and testes preserved in Bouin’s fluid then transferred to 70% Industrial Methylated Spirits (IMS) approximately forty-eight hours later: Coagulating gland, Prostate, Epididymides, Seminal vesicles, Ovaries, Testes, Mammary gland, Uterus/Cervix, Pituitary, Vagina.
All tissues were despatched to the Test Site for processing. The tissues from control and 1000 mg/kg bw/day dose group animals, any animals dying during the study, and any animals which failed to mate or did not achieve a pregnancy were prepared as paraffin blocks, sectioned at a nominal thickness of 5 μm and stained with Haematoxylin and Eosin for subsequent microscopic examination. In addition, sections of testes and epididymides from all control and 1000 mg/kg bw/day males were also stained with Periodic Acid-Schiff (PAS) stain and examined.
Microscopic examination was conducted by the Study Pathologist.
A peer review of the histopathology examination was performed by the Principal Investigator at the Test Site.

Ovaries and uterine content:

For all females, the uterus was examined for signs of implantation and the number of uterine implantations in each horn was recorded. This procedure was enhanced; as necessary, by staining the uteri with a 0.5% ammonium polysulphide solution (Salewski 1964).

Fetal examinations:

PARAMETERS EXAMINED
The following parameters were examined in offspring: Number of offspring born, number and sex of offspring alive recorded daily and reported on Day 1 and 4 post partum, clinical condition of offspring from birth to Day 5 post partum, individual offspring and litter weights on Day 1 and 4 post partum, physical Development and pathology.

GROSS EXAMINATION OF DEAD PUPS:
Dying and dead offspring during the study were subjected to a full external and internal examination, and any macroscopic abnormalities were recorded.

POST-MORTEM EXAMINATION
Surviving offspring were terminated via intracardiac overdose of sodium pentobarbitone. All offspring, including those dying during the study, were subjected to a full external and internal examination, and any macroscopic abnormalities were recorded.

Statistics:

The following parameters were subjected to statistical analysis:
Body weight and body weight change
Food consumption for females during gestation and lactation
Pre-coital interval and gestation length
Litter size and litter weights
Sex ratio
Water consumptions (Females)
Corpora lutea and implantation sites
Implantation losses and viability indices
Offspring body weight and body weight change
Offspring surface righting
Adult absolute and body weight-relative organ weights (Males)
For full detail please see 'Statistical Procedures Used' in any other information on materials and methods incl. tables section.

Indices:

Mating Performance and Fertility
The following parameters were calculated from the individual data during the mating
period of the parental generation.
i) Pre-coital Interval
Calculated as the time elapsing between initial pairing and the observation of positive
evidence of mating.
ii) Fertility Indices
For each group the following were calculated:
Mating Index (%) = (Number of animals paired ÷ Number of animals mated) x 100
Pregnancy Index (%) = (Number of animals mated ÷ Number of pregnant females) x 100
Gestation and Parturition Data
The following parameters were calculated for individual data during the gestation and
parturition period of the parental generation.
i) Gestation Length
Calculated as the number of days of gestation including the day for observation of
mating and the start of parturition.
ii) Parturition Index
The following was calculated for each group:
Parturition Index (%) = (Number of pregnant females ÷ Number of females delivering live offspring) x 100

Historical control data:

Not applicable.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
MORTALITY
There were no treatment related deaths during the study.
One female treated with 250 mg/kg bw/day was found dead during parturition. Macroscopic examination confirmed twelve dead pups in uterus whilst histopathological cause of this failure to deliver offspring was not established. In isolation and in view of the fact that similar incidents were not observed in high dose females this occurrence is considered not related to treatment.

CLINICAL OBSERVATIONS
A summary incidence of clinical observations is given in attached Table 2. Individual clinical observations are presented in attached Appendix 1.
No toxicologically significant clinical observations were detected during the study.
Incidents of increased salivation and fur stained by the test item were evident throughout the study in animals of either sex treated with 1000 mg/kg bw/day and in males treated with 250 mg/kg bw/day. Fur stained by the test item was also evident in females treated with 250 mg/kg bw/day and in animals of either sex treated with 50 mg/kg bw/day. Observations of this nature are often recorded following the oral administration of a coloured or unpalatable test item formulation and, in isolation, are considered not to be indicative of toxicity.
Noisy respiration was detected on one occasion in one female treated with 250 mg/kg bw/day on Day 21. In isolation and in view of the fact that there was no evidence of this observation in high dose animals this finding was considered to be of no toxicological importance.

BODY WEIGHTS
Group mean body weights, body weight changes and standard deviations are given in attached Table 3 and Table 4 (statistically significant differences are indicated). Group mean body weights are presented graphically in attached Figure 1 and Figure 2. Individual data are given in attached Appendix 2 and Appendix 3.
High dose males showed reductions in mean body weight gains throughout the treatment period. Statistical significance was achieved during weeks 1, 2 and 6 (P<0.01) and subsequent overall body weight gain was reduced. Females treated with 1000 mg/kg bw/day also showed a statistically significant reduction in mean body weight gain (P<0.05) during the lactation phase when compared to controls.
No such effects were evident in animals of either sex treated with 250 or 50 mg/kg bw/day. Males treated with 250 mg/kg bw/day showed a statistically significant reduction (P<0.05) during Weeks 2 and 6 only. In isolation and in the absence of any associated findings the intergroup differences were considered not to represent an adverse effect of treatment.

FOOD CONSUMPTION
Group mean food consumptions are given in attached Table 5 and are presented graphically in attached Figure 3 and Figure 4. Individual values for females during gestation and lactation are presented in attached Appendix 4.
No adverse effects on food intake or food efficiency were detected.

WATER CONSUMPTION
Group mean daily water consumptions are given in attached Table 7 (statistically significant differences are indicated). Individual and group mean water consumptions for females following mating and lactation are presented in attached Appendix 5.
No toxicologically important differences were detected in water consumption.
Females treated with 1000 mg/kg bw/day showed statistically significant increases (P<0.01-0.001) in water consumption throughout the gestation phase when compared to controls. Females treated with 250 mg/kg bw/day also showed statistically significant increases (P<0.05) during gestation phase. Increases in water consumption for females during the gestation phase were not supported by any associated findings. Observations of this nature are also commonly observed following the oral administration of an unpalatable test item formulation and as such are considered to be of no toxicological importance.

REPRODUCTIVE PERFORMANCE
Mating
A summary of adult performance is presented in attached Table 1. Group values and summary incidence for mating performance are presented in attached Table 8. Individual data are given in attached Appendix 6.
There were no treatment related effects detected on mating performance rates for animals of either sex treated with 1000, 250 or 50 mg/kg bw/day. All animals mated within the first five days of mating (i.e. the first oestrus opportunity).
One female treated with 50 mg/kg bw/day failed to achieve sexual maturation therefore did not mate. In isolation this occurance was considered fortuitous and not related to treatment.
Fertility
A summary of adult performance is given in attached Table 1. Group values for fertility, litter data and implantation losses are given in attached Tables 8, 9 and 10. Individual data are given in attached Appendices 6 to 8.
There were no treatment related effects detected on conception rates for animals of either sex treated with 1000, 250 or 50 mg/kg bw/day.
One female treated with 50 mg/kg bw/day and one control female failed to achieve pregnancy following evidence of mating. In the absence of any histopathological correlates in the reproductive organs to elucidate the cause of the non-pregnancy in these females and in the absence of similar effects present in high dose females this incidence was considered to be fortuitous and not related to treatment.
Gestation Length
A summary incidence of gestation lengths is given in attached Table 8. Individual lengths are given in attached Appendix 6.
There were no significant differences in gestation lengths with average delivery recorded on gestation Day 22 ½. The distribution for treated females was comparable to controls.
The two high dose females and one control female that showed slightly longer gestation periods (24 ½ and 23 ½ respectively) all had total litter losses post partum.

ORGAN WEIGHTS
Group mean absolute and body weight-relative male reproductive organ weights and standard deviations for test and control group animals are presented in attached Table 14 (statistically significant differences are indicated). Individual data are given in attached Appendix 12 and Appendix 13.
There were no toxicologically significant effects detected in the organ weights measured.
Males treated with 1000 or 250 mg/kg bw/day showed statistically significant reductions (P<0.05-0.01) in epididymis weight both absolute and relative to terminal body weight. In the absence of any histopathological correlates observed in the epididymides of these males and no effects detected on fertility these findings are considered of no toxicological importance.

NECROPSY
A summary incidence of necropsy findings for offspring and adults is given in attached Tables 15 and 16. Individual data are given in attached Appendices 14 and 15.
There were no toxicologically significant macroscopic abnormalities detected.
One male treated with 1000 mg/kg bw/day had red coloured contents in the stomach at necropsy. Due to the coloured nature of the test item, this finding is considered of no toxicological importance.
One control male had small and flaccid testes and small epididymides at necropsy. In the absence of treatment, this finding is considered fortuitous.
One female treated with 250 mg/kg bw/day had black coloured contents in the gastrointestinal tract at necropsy. One female treated with 50 mg/kg bw/day had an enlarged and fluid filled vagina, uterus and cervix. In the absence of any correlation to histopathological findings all macroscopic changes detected in females were considered to be of no toxicological importance.

HISTOPATHOLOGY
A complete histopathology report is attached.
There were no treatment related abnormalities detected during microscopic examinations.
All findings were those commonly observed in laboratory maintained rats of the age and strain employed and there were no differences in incidence or severity between control and treatment groups that were considered to be of toxicological significance.

Effect levels (maternal animals)

Dose descriptor:

NOEL

Effect level:

250 other: mg/kg bw/day AI

Based on:

test mat.

Basis for effect level:

other: other:

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects. Remark: "(under the conditions of the test, number of corpora lutea, implantation rate, postimplantation loss, litter size at first littercheck, body weights of pups or results of external examination gave no indication of embryotoxic or teratogenic effects

Details on embryotoxic / teratogenic effects:
The following assessment of litter response is generally based on those litters reared to termination on Day 5 post partum, although data available for females showing total litter loss has also been taken into consideration, where considered appropriate.

VIABILITY (OFFSPRING)
Group mean corpora lutea and implantation counts, litter size, implantation losses, survival indices and sex ratio are given in attached Tables 9 to 11. Individual data are given in attached Appendices 7 to 9.
At 1000 mg/kg bw/day, corpora lutea counts were lower than control, but this was considered to reflect normal biological variation. Although pre-implantation losses were lower than control, the number of implantations still remained lower at this dose level. Despite the lower implantation count, post implantation losses at 1000 mg/kg bw/day were noticeably higher than control, particularly when females that showed total litter loss were included, resulting in lower litter size on Day 1. By Day 4, differences in litter size from control attained statistical significance due to slightly higher post-natal losses between Days 1 and 4. This may reflect particularly good survival among control and other treated litter rather than an adverse effect on post-natal survival at 1000 mg/kg bw/day.
At 250 or 50 mg/kg bw/day offspring litter size and viability did not show any treatment related effects.
Sex ratio as assessed by percentage of male offspring at birth, Day 1 and 4 post partum did not show any significant differences in all treatment levels when compared to controls.

CLINICAL SIGNS (OFFSPRING)
Group mean values for surface righting reflex and a summary incidence of clinical signs are given in attached Tables 12 and 13. Individual values and observations are given in attached Appendices 10 and 11.
No obvious clinical signs of toxicity were detected for offspring from treated females. The incidence of clinical observations detected were slightly higher in litters from females treated with 1000 mg/kg bw/day, however, the type of observations were not considered to be adverse and the performance of the offspring during assessment of surface righting at Day 1 of age did not indicate any abnormalities.

BODY WEIGHT (OFFSPRING)
Group mean values for total litter weights, offspring body weights and body weight changes are given in attached Table 9. Individual values are given in attached Appendix 7.
There were no adverse effects on body weight and subsequent body weight gain of offspring to Day 4.
Mean litter weight values at Day 4 post partum showed statistically significant reductions (P<0.01) in litters from females treated with 1000 mg/kg bw/day when compared to control litters. Mean offspring body weight and body weight change for offspring from high dose females was unaffected therefore the statistically significant differences detected in mean litter weight at Day 4 post partum were considered to be due to smaller litter size of the litters from high dose females and of no toxicological significance.

ORGAN WEIGHTS (OFFSPRING)
Not applicable.

GROSS PATHOLOGY (OFFSPRING)
A summary incidence of necropsy findings for offspring is given in attached Table 15. Individual data are given in attached Appendix 14.
No treatment related macroscopic abnormalities were detected for interim death or terminal kill offspring. The incidental findings observed were those occasionally observed in reproductive studies of this type and were considered to be unrelated to toxicity of the test item.


HISTOPATHOLOGY (OFFSPRING)
Not examined.

OTHER FINDINGS (OFFSPRING)
Not applicable.

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Evaluation of Data

Treatment of Data

Data were processed to give group mean values and standard deviations where appropriate.

Data shown in the appendices are frequently rounded values for presentation purposes.  Group mean values are generally calculated using unrounded values therefore is it not always possible to calculate the exact group values from the individual values presented in the appendices.

For body weights and food consumptions during gestation, group mean values were calculated using data from females which were observed to give birth to offspring.

For body weights and food consumptions during lactation, group mean values were calculated using data from females with live young at Day 5 of lactation.

Applicant's summary and conclusion

Conclusions:

The oral administration of S190700 to rats by gavage, at dose levels of 50, 250 and 1000 mg/kg bw/day, resulted in treatment related effects at 1000 mg/kg bw/day. No such effects were detected at 250 or 50 mg/kg bw/day therefore the ‘No Observed Effect Level’ (NOEL) for reproductive/development toxicity was considered to be 250 mg/kg bw/day.

Executive summary:

Introduction.

The study was performed to screen for potential adverse effects of the test item on reproduction including offspring development and provides an initial hazard assessment for effect on reproduction. The study is compatible with the requirements of the recommendations of the OECD Guidelines for Testing of Chemicals No. 421 “Reproduction/Developmental Toxicity Screening Test” (adopted 27 July 1995).

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 ten male and ten female Wistar Han™:RccHan™:WIST strain rats, for up to eight weeks (including a two week maturation phase, pairing, gestation and early lactation for females), at dose levels of 50, 250 and 1000 mg/kg bw/day (incorporating a correction factor for 89.8% purity). A control group of ten males and ten females was dosed with vehicle alone (Distilled water).

Clinical signs, body weight change, dietary intake 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.

Adult males were terminated on Day 43, followed by the termination of all surviving females and offspring on Day 5post partum. All animals were subjected to a gross necropsy examination and histopathological evaluation of reproductive tissues was performed.

Results.

Adult Responses:

Mortality.

There were no treatment related deaths during the study.

Clinical Observations.

There were no toxicologically significant clinical observations detected during the study.

Body Weight.

High dose males showed reductions in body weight gains throughout the treatment period. Females treated with 1000 mg/kg bw/day showed a reduction in body weight gain during lactation.

No toxicologically significant body weight effects were evident in animals of either sex treated with 250 or 50 mg/kg bw/day.

Food Consumption and Food Efficiency.

No adverse effects on food intake or food efficiency were detected.

Water Consumption.

No toxicologically important differences were detected.

Reproductive Screening:

Mating.

There were no treatment related effects detected on mating rates for animals of either sex treated with 1000, 250 or 50 mg/kg bw/day.

Fertility.

There were no treatment related effects detected on conception rates for animals of either sex treated with 1000, 250 or 50 mg/kg bw/day.

Gestation Lengths.

There were no differences in gestation lengths. The distribution for treated females was comparable to controls.

Litter Responses:

Offspring Litter Size, Sex Ratio and Viability.

Of the litters born no toxicologically significant findings were detected on litter size, sex ratio and viability at Day 1 and 4post partum. 

Offspring Growth and Development.

There were no toxicologically significant effects detected in offspring growth and development parameters measured.

Offspring Observations.

No toxicologically significant effects were detected for offspring from all treatment groups.

Pathology:

Necropsy.

No toxicologically significant macroscopic abnormalities were detected.

Organ Weights.

No toxicologically significant organ weights findings were detected.

Histopathology.

No treatment related microscopic abnormalities were detected.

Conclusion.

 The oral administration of S190700 to rats by gavage, at dose levels of 50, 250 and 1000 mg/kg bw/day, resulted in treatment related effects at 1000 mg/kg bw/day. No such effects were detected at 250 or 50 mg/kg bw/day therefore the ‘No Observed Effect Level’ (NOEL) for reproductive/development toxicity was considered to be 250 mg/kg bw/day.