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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
two-generation reproductive toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
05 June 2015 to 26 July 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report date:
2016

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)
Deviations:
no
GLP compliance:
yes
Limit test:
no
Justification for study design:
The test and control items were administered to the appropriate F0 and F1 animals by once daily oral gavage for 10 weeks prior to mating, and then throughout mating, gestation and lactation until termination after the resultant litters had reached Day 21 of lactation. The F1 pups selected to form the F1 adult generation commenced dosing within 1 week of weaning (at ca 4 weeks of age).
The volume for each animal was based on the most recent body weight measurement except during late gestation; from Day 16 until parturition was completed, the dose volume was determined by the weight of the animal on Day 16 of gestation (see Appendix 1 for details of deviation). The doses were given using a syringe with attached gavage cannula.
For both generations, females were not dosed if they were found to be littering at the time that dose administration was scheduled.

The Han Wistar rat was chosen as the animal model for this study as it is an accepted rodent species for preclinical toxicity testing by regulatory agencies and the Test Facility has sufficient historical control data in this species and strain.
The total number of animals used in this study was considered the minimum required to properly characterise the effects of the test item. This study was designed such that it did not require an unnecessary number of animals to accomplish its objectives.
The oral gavage route of administration was selected for this study as this route was defined by the Sponsor as a possible route of human exposure.

The dose levels were agreed with the Sponsor following evaluation of a previous twenty-eight day repeated dose oral (gavage) toxicity study in the rat (OECD Guideline 407), a reproduction / developmental toxicity screening of study oral gavage in the rat (OECD Guideline 421; Charles River Study No. 496381) and a Prenatal Developmental Toxicity Study in the rat (OECD Guideline 414; Charles River Study No. 497233) performed on behalf of the Sponsor.

F0 and F1 male rats were euthanised once the majority of females reached the end of lactation. F0 and F1 females were euthanisd at or shortly after weaning (ca. Day 21 of lactation). Pups not selected for post-weaning analysis were killed at the same time as thier mother. Animals 10 days of age or more were killed by exposure to carbon dioxide followed by exsanguination. Animals less than 10 days of age were killed by intra-peritoneal injection of sodium pentobarbitone followed by exsanguination. Animals were euthanised rotating across dose groups such that similar numbers of animals from each group, including controls were necropsied throughout each day of necropsy.

Test material

Constituent 1
Details on test material:
- Physical state: extremely viscous amber liquid
- Analytical purity:
- Lot/batch No.: E00031-68-1
- Expiration date of the lot/batch: 16 October 2010
- Storage condition of test material:room temperature in the dark, under nitrogen

Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- lot/batch No.of test material: E00031-541
- Expiration date of the lot/batch: 01 November 2016
- Purity test date: > 99%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Ambient temperature in the dark

Test animals

Species:
rat
Strain:
Wistar
Details on species / strain selection:
The Han Wistar rat was chosen as the animal model for this study as it is an accepted rodent species for preclinical toxicity testing by regulatory agencies and the Test Facility has sufficient historical control data in this species and strain.
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River UK Ltd, Margate, Kent, UK.
- Age at study initiation: (P) Males: 7-8 weeks; females: 6 - 7 weeks; (F1) approximately 4 wks
- Weight at study initiation: (P) Males: 164-238 g; Females: 114-164 g; (F1) Males: 248-256 g; Females: 173-181 g
- Housing: All animals were initially housed 2 or 3 per cage in appropriately sized polycarbonate cages with stainless steel grid tops and bottoms. A few days prior to pairing for mating, the males were transferred to individual cages which females were then transferred to for mating. Males were re-caged to their original cage-mates.
- Diet (e.g. ad libitum): ad libitum, except during designated procedures
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 12 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17-25 °C
- Humidity (%): 43-69%
- Air changes (per hr): At least 10 air changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours light / 12 hours dark
IN-LIFE DATES: From: 08 June 2015 To: 04 December 2015

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
arachis oil
Details on exposure:
SDS VRF-1 breeder diet was provided ad libitum throughout the study, except during designated procedures. The feed was analysed by the supplier for nutritional components and environmental contaminants. Results of the analysis were provided by the supplier and are retained at the Test Facility.There were no known contaminants in the feed that would interfere with the objectives of the study.

VEHICLE
- Volume dosage: 4 mL/kg
The control formulation, Arachis Oil BP, was stored in a refrigerator set to maintain 4°C, and dispensed daily. The control formulation was removed from the refrigerator and stirred continuously from at least 30 minutes prior to dosing until dosing was completed each day. Any residual volumes were discarded.
Details on mating procedure:
A few days prior to the initiation of mating, the males were separated into individual solid bottomed cages. Pairing was on a 1:1 or 1:2 (male: female) basis in ascending numerical order. Each female was transferred to the cage of its appropriate co-group male during the evening of Day 71 of dosing (where Day 1 was first day of dosing) from 19.00 onwards.
Vaginal lavages were taken each morning until mating occurred and the stage of oestrus observed in each vaginal lavage was recorded. The day of detection of a copulatory plug in situ and/or of sperm in the lavage was designated Day 0 of gestation.
The pairing period was a maximum of 14 nights. If evidence of mating was not observed by the end of the pairing period, the female was separated from the male during the morning following the last night of pairing and treated as if it had mated during that night.
For each female the time taken to show a positive mating sign and the number of failed opportunities to mate (oestruses passed without a sign of mating) were evaluated.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Duplicate top, middle and bottom (duplicate middle only for control and Group 3) samples (1 mL) for each sampling time point were sent to the analytical laboratory. Triplicate top, middle, and bottom samples (triplicate middle only for control and Group 3) were maintained at the Test Facility as backup samples. Samples were kept in a refrigerator set to maintain 4ºC. After acceptance of the analytical results, backup samples were discarded.
For concentration, the criterion for acceptability was a mean sample concentration result within or equal to ± 10% of theoretical concentration, with individual samples within ± 20%. For homogeneity, the criterion for acceptability was a relative standard deviation (RSD) of concentrations of = 10% for each group.
Duration of treatment / exposure:
F0 animals were dosed for 10 weeks prior to mating, and then throughout mating, gestation and lactation until termination after the (F1) litter had reached Day 21 of lactation. From each dose group, up to 24 males and 24 females were retained for post weaning assessments. These animals were dosed for 10 weeks after weaning, and then throughout mating, gestation and lactation until termination after the (F2) litter had reached Day 21 of lactation.
Frequency of treatment:
daily
Details on study schedule:
F1 dosing commenced within 1 week of weaning (ca. 4 weeks of age). From each group, 24 males and females were selected for post-weaning assessments by selecting up to one male and one female from each litter. Pups were selected by median weight, removed from their mother on Day 21 of lactation, and individually identified and housed in their new cage. These animals were dosed for 10 weeks after weaning, throughout mating, gestation and lactation until termination after the F2 litter had reached Day 21 of lactation. Pups not selected for post-weaning assessments remained with their mother until sacrifice.
Sexual maturation assessments commenced at 28 and 35 days of age for females and males respectively. Females were examined for vaginal opening and males were examined for balano-preputial separation. Body weights were recorded on the day of sexual maturation.
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day
Dose / conc.:
100 mg/kg bw/day
Dose / conc.:
300 mg/kg bw/day
Dose / conc.:
1 000 mg/kg bw/day
No. of animals per sex per dose:
F0: 28 animals per sex per dose; F1: 24 animals per sex per dose
Control animals:
yes, concurrent vehicle
Details on study design:
The test and control items were administered to the appropriate F0 and F1 animals by once daily oral gavage for 10 weeks prior to mating, and then throughout mating, gestation and lactation until termination after the resultant litters had reached Day 21 of lactation. The F1 pups selected to form the F1 adult generation commenced dosing within 1 week of weaning (at ca 4 weeks of age). The volume for each animal was based on the most recent body weight measurement except during late gestation; from Day 16 until parturition was completed, the dose volume was determined by the weight of the animal on Day 16 of gestation. The doses were given using a syringe with attached gavage cannula. For both generations, females were not dosed if they were found to be littering at the time that dose administration was scheduled.
Positive control:
No

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes
- All animals were examined at least once a day.

DETAILED CLINICAL OBSERVATIONS: Yes
- Amimals were removed from the cage and examined weekly commencing Week -1 throughout the study.

BODY WEIGHT: Yes
- Male body weights were recorded once during pre-treatment and weekly throughout the dosing period. F0 female body weights were recorded once during pre-treatment, weekly until pairing for mating, on Days 0 (the day of detection of positive mating sign), 7, 14, 16 and 20 of gestation and on Days 1 (day of birth of litter), 7, 14 and 21 of lactation. A weekly regimen was applied to females that had not shown a positive mating sign, until parturition or termination. Retained F1 animals body weights were recorded weekly commencing on a suitable day within one week of weaning of the majority of litters until termination for males or until pairing for mating for the females; during gestation and lactation, weighing of F1 females followed the same regimen as F0 females.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption was quantitatively measured weekly commencing at the start of Week -1 (F0 animals) or from a suitable day within one week of weaning of the majority of animals (F1 animals) until pairing for mating. Males – Weekly measurements recommenced after the mating period. Mated Females – Measured over Days 0-7, 7-14 and 14-20 of gestation, and over Days 0-7, 7-14 and 14-21 of lactation. A weekly regimen was applied to females that had not shown a positive mating sign, until parturition or termination.
Oestrous cyclicity (parental animals):
Over a 2-week period prior to the initiation of mating and throughout the mating period, vaginal lavages were taken each morning and the stages of oestrous observed was recorded.
Sperm parameters (parental animals):
From the first 10 males/group from both the F0 and F1 generations, the right cauda epididymis was placed into Medium 199 (as per SOP/PAT/069) and the sperm were allowed to “swim out” into the medium. An appropriate dilution of the sperm suspension was prepared and examined using a Hamilton Thorne sperm motility analyser.
The remaining portion of the cauda epididymis was minced and suspended. Dilutions of this sperm suspension were counted using a haemocytometer to obtain a total sperm count which was expressed per sample. From all samples of the sperm suspensions described in the preceding paragraph, a sperm smear was prepared and stained with eosin Y solution. From the Group 1 and 4 animals (both generations), at least two hundred sperm per animal were evaluated for morphological abnormalities using criteria described by Wyrobek and Bruce (1975).
One testis was decapsulated and homogenised. The homogenate was sonicated to reduce tissue debris, if required. The number of homogenisation resistant spermatids in dilutions of this suspension were counted using a haemocytometer to obtain a total spermatid count which was expressed per testis and per gram of testis.
Litter observations:
The day of birth of the litter (day on which first pups were born) was designated Day 0 of lactation. The duration of gestation in days was calculated. The numbers of live and dead pups born in each litter was recorded as soon as possible after completion of parturition on Day 0 of lactation. The live pups were counted and examined for the presence of milk in the stomach and for any externally visible abnormalities daily up to at least Day 21 of lactation. These pups were weighed en masse, sexes separately, on Days 1, 4, 7 and 14 of lactation. On Day 21 of lactation they were weighed individually. Deficiencies in maternal care were recorded: inadequate construction or cleaning of the nest, pups left scattered and cold, physical abuse of pups, or apparently inadequate lactation or feeding.
Postmortem examinations (parental animals):
SACRIFICE
- Males - once the majority of females reached the end of lactation.
- Females - At or shortly after weaning (ca. Day 21 of lactation).
Animals 10 days of age or more were killed by exposure to carbon dioxide followed by exsanguination. Animals less than 10 days of age were killed by intra-peritoneal injection of sodium pentobarbitone followed by exsanguination. Animals were euthanized rotating across dose groups such that similar numbers of animals from each group, including controls were necropsied throughout each day of necropsy.

GROSS NECROPSY
- Animals were subjected to a complete necropsy examination, which included evaluation of the carcass and musculoskeletal system; all external surfaces and orifices; cranial cavity and external surfaces of the brain; and thoracic, abdominal, and pelvic cavities with their associated organs and tissues. The reproductive tract of all adult females was examined for signs of implantation, the number of implantation sites were recorded. Necropsy procedures were performed by qualified personnel with appropriate training and experience in animal anatomy and gross pathology. A veterinary pathologist, or other suitably qualified person, was available.

HISTOPATHOLOGY / ORGAN WEIGHTS
Histopathological evaluation was performed by a board-certified veterinary pathologist with training and experience in laboratory animal pathology. A detailed qualitative examination of the testes was made, taking into account the tubular stages of the spermatogenic cycle. The examination was conducted in order to identify treatment-related effects such as missing germ cell layers or types, retained spermatids, multinucleate or apoptotic germ cells and sloughing of spermatogenic cells into the lumen. Any cell-specificity or stage-specificity of testicular findings were noted. The examination of the ovaries included quantification of the primordial and growing oocytes, and the confirmation of the presence or absence of the corpora lutea.

The following organs were weighed at necropsy: Brain, Epididymis, Adrenal gland, Pituitary gland, Prostate gland, Thyroid gland, Kidney, Liver, Ovary, Spleen, Testis and Uterus. Organ weights were not recorded for animals found dead or euthanised in poor condition or in extremis. Paired organs were weighed separately but have been reported together. Terminal body weights were used for organ weight analysis.
Postmortem examinations (offspring):
Termination occured onced the litter had reached Day 21 of lactation.
From each litter, two male and two female pups (where they were available) were necropsied. This consisted of external examination followed by macroscopic examination of the tissues and organs of the cranial, thoracic and abdominal cavities in situ. Samples of any grossly abnormal tissues were preserved in 10% formalin or other appropriate fixative. From one of the two pups of each sex (where they were available), the weights of the brain, spleen and thymus were recorded (as was as a terminal body weight), and these organs were preserved. Representative samples of any abnormal tissues from any of the pups were also preserved. The carcasses were then discarded.
Where 2 pups of either sex were not available for necropsy, or 1 pup of each sex were not available for organ weight collection, additional pups of the opposite sex were necropsied/weighed such that 4 animals per litter were necropsied and 2 animals per litter had organs weighed as far as was possible.
The remaining pups in each litter were checked for externally visible abnormalities at the time of killing. Any found to have such an abnormality was necropsied as described in the preceding paragraph. The remaining carcasses were discarded.
Statistics:
Tests were applied to determine the statistical significance of observed differences between the control group and groups receiving test item. Unless otherwise stated, all statistical tests were two-sided and performed at the 5% significance level using in house software. Pairwise comparisons were only performed against the control group. Body weight and food consumption were analysed for homogeneity of variance using the ‘F-Max’ test. If the group variance appeared homogeneous, a parametric ANOVA was used and pairwise comparisons were made using Fisher’s F-protected LSD method via Student’s t-test ie pairwise comparisons were made only if the overall F-test was significant. If the variances were heterogeneous, log or square root transformations were used in an attempt to stabilise the variances. If the variances remained heterogeneous, then a Kruskal-Wallis non-parametric ANOVA was used and pairwise comparisons were made using chi squared protection (Via z tests, the non-parametric equivalent of Student’s t test). Organ weight data was analysed as above, and by analysis of covariance (ANCOVA) using terminal body weight as the covariate.
Reproductive indices:
For each group the fertility index (male and female) and gestation indices were calculated. For each litter and group the birth indices, live birth indices, viability indices, lactation indices and the overall survival indices were calculated.
Offspring viability indices:
For each group, the following reproductive indices were calculated: Fertility Index (male and female) and gestation index.
For each litter and group: birth index, live birth index, viability index, lactation index and overall survival index.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:
effects observed, non-treatment-related
Description (incidence and severity):
Slow respiration and subdued behaviour. A swelling was observed in the right lower ventral abdomen which was noted as a firm brown subcutaneous mass involving the nipple at necropsy; grossly the nipple itself was reddened and damaged with pale material at the centre; inflammation and necrosis of the mammary gland was noted at histopathological examination.
Dermal irritation (if dermal study):
not examined
Mortality:
mortality observed, non-treatment-related
Description (incidence):
There were no test item-related deaths - there were a number of adult animals found dead or prematurely euthanised however the incidence and circumstances surrounding these deaths indicated no relationship to the test item.
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:
no effects observed
Haematological findings:
not examined
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
not examined
Behaviour (functional findings):
no effects observed
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Histopathological findings: neoplastic:
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

Effect levels (P0)

Key result
Dose descriptor:
NOEL
Effect level:
ca. 1 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
mortality
body weight and weight gain
food consumption and compound intake
ophthalmological examination
gross pathology
histopathology: non-neoplastic
histopathology: neoplastic
reproductive performance
Remarks on result:
not determinable due to absence of adverse toxic effects

Target system / organ toxicity (P0)

Critical effects observed:
no

Results: P1 (second parental generation)

General toxicity (P1)

Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality:
mortality observed, non-treatment-related
Description (incidence):
There were a number of adult animals found dead or prematurely euthanised however the incidence and circumstances surrounding these deaths indicated no relationship to the test item.
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:
no effects observed
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
no effects observed
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
no effects observed

Reproductive function / performance (P1)

Reproductive function: oestrous cycle:
no effects observed
Reproductive function: sperm measures:
no effects observed
Reproductive performance:
effects observed, non-treatment-related
Description (incidence and severity):
Pertinent pathology findings in relation to animals that failed to mate or produce a live litter are discussed in the pathology report; in none of these cases was the test item considered to be a factor.

Effect levels (P1)

Key result
Dose descriptor:
NOEL
Effect level:
ca. 1 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
mortality
body weight and weight gain
food consumption and compound intake
ophthalmological examination
gross pathology
histopathology: non-neoplastic
histopathology: neoplastic
reproductive performance
Remarks on result:
not determinable due to absence of adverse toxic effects

Target system / organ toxicity (P1)

Critical effects observed:
no

Results: F1 generation

General toxicity (F1)

Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality / viability:
mortality observed, non-treatment-related
Description (incidence and severity):
In both generations, there were a number of pups found dead or prematurely euthanised, however the incidence and circumstances surrounding the deaths indicated no relationship to the test item.
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:
no effects observed
Haematological findings:
not examined
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
not examined
Sexual maturation:
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings:
no effects observed

Developmental neurotoxicity (F1)

Behaviour (functional findings):
no effects observed

Developmental immunotoxicity (F1)

Developmental immunotoxicity:
not examined

Effect levels (F1)

Key result
Dose descriptor:
NOEL
Generation:
F1
Effect level:
ca. 1 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
sexual maturation
clinical signs
mortality
body weight and weight gain
food consumption and compound intake
ophthalmological examination
gross pathology
histopathology: non-neoplastic
histopathology: neoplastic
developmental neurotoxicity

Target system / organ toxicity (F1)

Critical effects observed:
no

Results: F2 generation

General toxicity (F2)

Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality / viability:
mortality observed, non-treatment-related
Description (incidence and severity):
In both generations, there were a number of pups found dead or prematurely euthanised, however the incidence and circumstances surrounding the deaths indicated no relationship to the test item.
Body weight and weight changes:
no effects observed
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:
no effects observed
Histopathological findings:
no effects observed

Developmental neurotoxicity (F2)

Behaviour (functional findings):
no effects observed

Developmental immunotoxicity (F2)

Developmental immunotoxicity:
not examined

Effect levels (F2)

Key result
Dose descriptor:
NOEL
Generation:
F2
Effect level:
ca. 1 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
clinical signs
mortality
body weight and weight gain
gross pathology
histopathology: non-neoplastic
histopathology: neoplastic
developmental neurotoxicity

Target system / organ toxicity (F2)

Critical effects observed:
no

Overall reproductive toxicity

Key result
Reproductive effects observed:
no

Applicant's summary and conclusion

Conclusions:
In conclusion, once daily oral gavage administration of EXP0700332 to rats at dose levels of up to 1000 mg/kg/day from 10 weeks prior to mating, and then throughout mating, gestation and lactation was well tolerated and had no effect upon the reproductive performance of either the initial (F0) generation or the subsequent (F1) generation. Therefore, under the conditions of this study the no observed effect level (NOEL) was considered to be 1000 mg/kg/day.
Executive summary:

This study was designed to provide general information concerning the effects of EXP0700332 on the reproductive performance of rats when administered once daily via oral gavage over two consecutive generations. F0 animals were dosed for 10 weeks prior to mating, and then throughout mating, gestation and lactation until termination after the (F1) litter had reached Day 21 of lactation. From each dose group, up to 24 males and 24 females were retained for post weaning assessments. These animals were dosed for 10 weeks after weaning, and then throughout mating, gestation and lactation until termination after the (F2) litter had reached Day 21 of lactation. Both F0 and F1 animals were dosed at 0, 100, 300 and 1000 mg/kg/day. The following parameters and end points were monitored/evaluated in this study: clinical signs, body weights, body weight gains, food consumption, oestrous cycles, mating performance, fertility, pregnancy performance (including difficulty or prolongation of parturition), deficiencies in maternal care, offspring growth and survival, assessment of sexual maturation (F1 generation), organ weights, macroscopic pathology, microscopic pathology and sperm evaluations (including motility, count and morphological evaluation). There were no test item related effects on the parameters and end points monitored/evaluated in this study.

In conclusion, once daily oral gavage administration of EXP0700332 to rats at dose levels of up to 1000 mg/kg/day from 10 weeks prior to mating, and then throughout mating, gestation and lactation was well tolerated and had no effect upon the reproductive performance of either the initial (F0) generation or the subsequent (F1) generation. Therefore, under the conditions of this study the no observed effect level (NOEL) was considered to be 1000 mg/kg/day.