Methyl 2-benzoylbenzoate

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

September 2014-March 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Methyl 2-benzoylbenzoate

EC Number:

210-112-3

EC Name:

Methyl 2-benzoylbenzoate

Cas Number:

606-28-0

Molecular formula:

C15H12O3

IUPAC Name:

methyl 2-benzoylbenzoate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): RCX 14-672
- Chemical name: methyl-2-benzoylbenzoate
- Substance type: organic
- Physical state: white to light yellowish powder
- Analytical purity: >99%
- Impurities (identity and concentrations): unknown
- Lot/batch No.: N14003
- Expiration date of the lot/batch: 30 November 2015
- Stability under test conditions: stable
- Storage condition of test material: controlled room temperature (15-25°C, below 70 RH%), protected from light and humidity

Specific details on test material used for the study:

Identification: RCX 14-672
Chemical name: methyl-2-benzoylbenzoate
Batch no.: N14003
CAS no.: 606-28-0
EC no.: 210-112-3
Molecular formula: C15H12O3
Molecular mass: 240.3 g/mol
Description: white to light yellowish powder
Purity: >99% (gas chromatography)
Water solubility: 117.7 mg/l
Test item storage: at room temperature, protected from light
Stability: stable under storage conditions
Expiry date: 30 November 2015

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Species and strain: Crl:WI rats
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, D-97633, from SPF colony
- Age at study initiation: young adult rats, approximately 11 weeks old at starting and 13 weeks at mating.
- Weight at study initiation: males: 349-389 g, females: 230-271 g.
- Housing: standard laboratory conditions
- Diet (e.g. ad libitum): Ssniff® SM R/M-Z+H "Autoclavable complete feed
- Water (e.g. ad libitum): tap water from municipal supply from 500 ml bottle ad libitum.
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3 °C
- Humidity (%): 35 - 70 %
- Air changes (per hr): 15-20 air exchanges/hour
- Photoperiod (hrs dark / hrs light): 12 hours/12 hours light, from 6.00 a.m. to 6.00 p.m.

IN-LIFE DATES: From: 2 September 2014 to 25 October 2014

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

polyethylene glycol

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test item was formulated in the vehicle (polyethylene glycol 400), as a visibly stable homogenous formulation at the appropriate concentrations according to the selected dose level and volume, in the Pharmacy of CiToxLAB Hungary Ltd. Formulations were prepared in up to 8-day intervals and stored at room temperature, based on the stability assessment results. Stability of the test item in the selected vehicle was assessed in the conditions employed in the study. Analysis of RCX 14-672 formulation samples of 1-250 mg/mL concentration range showed no decrease of concentration. The formulation was considered stable for 8 days at room temperature.

VEHICLE
The vehicle was selected based on the formulation and analytical trials.
- Name: Poly(ethylene glycol) 400
- Lot/Batch number: BCBL5307V
- Manufacturer: Sigma-Aldrich Co.
- Expiry/Retest Date: January 2015
- Storage: Room temperature

Details on mating procedure:

Mating began after the animals had attained full sexual maturity, 2 weeks after the initiation of treatment, with one female and one male from the same dose group (1:1 mating) in a single cage. Females remained with the same male until copulation occurred, for up to 17 days.

A vaginal smear was prepared daily during the mating period and stained with 1% aqueous methylene blue solution. The smears were examined with a light microscope. The presence of a vaginal plug or sperm in the vaginal smear was considered as evidence of copulation (Day 0 of pregnancy as defined by the relevant guidelines). Sperm positive females were housed individually.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analysis of test item formulations for concentration and homogeneity was performed in the Analytical Laboratory of CiToxLAB Hungary Ltd. Top, middle and bottom duplicate samples were taken and analysed from test item formulations and all concentrations. Sample analysis was performed on 3 occasions for homogeneity (top, mid and bottom) and all prepared formulations were analysed for concentration. One set was collected for analysis and one set as a back-up, if required for any confirmatory analyses. Similarly, one sample was taken on each occasion in duplicate from the
Group 1 (control) solution to confirm the absence of test item.

Details on study schedule:

Test item or negative control treated animals were administered the dosing formulations daily on a 7 days/week basis by oral gavage using a tipped gavage needle attached to a syringe. A constant volume of 4 mL/kg bw was administered to all animals. The actual volume administered was calculated and adjusted based on most recent individual body weights.

Dosing of both sexes began after 5 days of acclimation and 2 weeks before mating and continued up to the day before necropsy. The mating began after the animals had attained full sexual maturity and continued in both sexes during the mating period. Males were dosed for up to 30 days (14 days pre-mating and up to 16 days mating/post-mating) and then euthanized and subjected to necropsy examination.

Females were dosed for 14 days pre-mating, during the mating period, through gestation and until the day before the necropsy (at least 4 days post-partum dosing). The day of birth (when parturition was complete) was defined as Day 0 post-partum. Females showing no-evidence of copulation were sacrificed 23-24 days after the end of the mating period (one in the low and one mid dose, respectively, with no delivery). All F1 offspring were terminated on Day 4 post-partum. In order to allow for overnight fasting of dams prior to urine collection on PPD5, the offspring were euthanized on PPD/PND 4 and the dams on PPD/PND 5.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

31.25 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

125 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

500 mg/kg bw/day (nominal)

No. of animals per sex per dose:

12/sex/dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
The dose levels were selected based on available data and information from previous experimental work, including the results of a repeated dose range finding study in the rat. The aim was to induce toxic effects but ideally no death or suffering at the highest dose and a NOAEL at the lowest dose. Based on high liver weight changes at 1000 mg/kg bw/day (>60% above control), the highest dose levels selected was 500 mg/kg bw/day. The oral route was selected as it is a possible route of exposure to the test item in humans.

- Rationale for animal assignment:
All parental (P) animals were sorted according to body weight by computer and divided into weight ranges. There were an equal number of animals from each weight group in each of the experimental groups assigned by randomization to ensure that animals of all test groups were as close as practicable to a uniform weight. The grouping was controlled by SPSS/PC+4.0 software according to the actual body weight, thereby verifying the homogeneity/variability between/within the groups and cages. Males and females were randomized separately.

Positive control:

Not applicable

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
Animals were inspected for signs of morbidity and mortality twice daily, at the beginning and the end of the working day. General clinical observations were performed daily, after treatment at approximately the same time with minor variations, or in the afternoon as practical during the working day, as no peak period of effects was noted after dosing during the first few days of treatment.

DETAILED CLINICAL OBSERVATIONS: Yes
All animals were monitored for pertinent behavioural changes, signs of difficult or prolonged parturition and all signs of toxicity including mortality. Any changes were recorded including their onset, degree and duration as applicable. Detailed examinations were performed once before the first exposure (to allow for within-subject comparisons), then at least weekly, in the morning or before treatment. These observations were performed outside the home cage in a standard arena, at similar day times as practical. The animals were monitored for changes in skin, fur, eyes, mucous membranes, occurrence of secretions and excretions, and autonomic activity (e.g. lachrymation, piloerection, pupil size, unusual respiratory pattern), or changes in gait, posture and response to handling as well as the presence of clonic or tonic movements, stereotypies (e.g. excessive grooming, repetitive circling), difficult or prolonged parturition or bizarre behaviour (e.g. self-mutilation, walking backwards); special attention were directed towards the observation of tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma.

BODY WEIGHT: Yes
All adult animals were weighed with an accuracy of 1 g for randomization purposes, then on Day 0, at least weekly thereafter and at termination. Parent females were weighed on gestation Days GD0, 7, 14 and 20 and on post partum Days PPD0 (within 24 hours after parturition), PPD4 and before termination. Body weights of the female animals were additionally taken on gestational Days GD10 and 17 in order to give accurate treatment volumes but these data were not evaluated statistically.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
Food consumption was determined by re-weighing the non-consumed diet with a precision of 1 g on Day 7, then at least weekly (on the days of body weight measurements).

HAEMATOLOGY AND CLINICAL CHEMISTRY: Yes
All animals selected for blood sampling were fasted (overnight period of food deprivation, after the litter had been culled). Blood samples were collected by cardiac puncture under pentobarbital anaesthesia, immediately prior to scheduled necropsy. For terminal blood sampling three samples were taken from each selected animal (subgroup B, 5 males and 5 or 6 females/group), one for haematology (in tubes with K3-EDTA as anticoagulant, 1.6 mg/mL blood), one for blood clotting times (in tubes with sodium citrate as anticoagulant) and one to obtain serum (in tubes with no anticoagulant) for clinical chemistry

- Parameters checked: see tables in Report.

URINALYSIS: Yes
Parameters chekced: leukocytes, nitrite, pH, protein, glucose, urobilinogen, bilirubin, ketones, blood eythrocytes, specific gravity, sediment, volume, colour/appearance.

NEUROBEHAVIOURAL EXAMINATION: Yes
Five males and 5 females/group: Assessment of potential test item related neurotoxicity was performed in the morning and prior to dosing, during the last exposure week (males on Day 27; females on PPD 4). Selected animals were subjected to the functional observation battery including quantitative assessment of grip strength (manual and instrumental) and measurement of landing foot splay and fore/hind limb grip strength. Qualitative and quantitative assessments of motor activity were performed.

To measure the landing foot splay, the fore/hind paws of the rat were painted with ink and the rat was dropped from a horizontal position onto the appropriate record sheet covering the examination table. The distance between the two resulting ink spots for the hind limbs was measured.
Fore/hind limb grip strength was measured using a grip strength meter (Model GS3, Bioseb, Chaville, France), an instrument designed to quantify objectively rodent muscular strength, in order to identify and assess quantitatively any potential effect of the test item. The rats were held appropriately such that the fore limbs were allowed to grip the support bar and gently pulled back until they released the bar; the device measured the maximum grip strength. This was performed 3 times for each animal on each test day. The procedure was repeated with the hind limbs and the appropriate grip
support. The results were tabulated with individual and mean data.

Manual assessment of sensory reactivity to different types of stimuli (e.g. auditory, visual and proprioceptive), grip strength and motor activity were conducted and the general physical condition and behaviour of animals was tested. A modified Irwin test was performed. Parameters including body position, locomotor activity, respiration rate, respiration type, piloerection, head searching compulsive biting or licking, circling, upright walking, retropulsion, jumping, exophthalmos, twitches, clonic convulsions, tonic convulsions, tremor, startle, transfer arousal, spatial locomotion, gait, posture, limb position, finger approach, finger withdrawal, touch escape response, diarrhoea, diuresis, visual placing, grip strength, body tone, corneal reflex, pinna, toe pinch, grasping reflex, positional struggle, skin, mucous membrane colour, salivation, palpebral closure, lachrymation, limb tone, abdominal tone, tail pinch, righting reflex, and/or vocalisation were evaluated using a scoring system, where score “0” was given when the behaviour or reaction of the animal was considered normal, and -1 or -2, or +1 and +2 was given if the response was less than or more than expected in an
untreated animal.

Quantitative assessment of motor activity was conducted using Automatic Monitoring System of rat locomotor activity SMART v. 2.5 (Harvard Apparatus, Germany). Locomotor activity was monitored by placing each animal individually into an openfield for 1 hour observation time, when DVD recording of movement was made. Recording was made for a duration of 60 minutes, under dim-light and undisturbed conditions. The DVD was analysed with “SMART” software after all recordings were made to produce the appropriate parameters. Obtained data were evaluated for
distance travelled in 5-minute segments.

Oestrous cyclicity (parental animals):

Females were allowed to litter and rear their offspring. The delivery process was observed as carefully as possible. Any evidence of abnormal deliveries was recorded. The duration of gestation was recorded and was calculated from Day 0 of pregnancy until the completion of parturition.
Dams were observed for signs of nest building with the bedding material and for covering their new-borns. Evidence of suckling was observed by the presence of milk in the pups' stomach. All observations were recorded.

Litter observations:

Each litter was examined as soon as possible after delivery to establish the number and sex of pups, stillbirths, live births, runts (pups that are apparently smaller than normal pups) and to detect the presence of gross abnormalities.

Live pups were counted, sexed, weighed individually within 24 hours of parturition (PND0 or PND1) and on PND4, with accuracy of 0.01g. All litters were checked daily for the number of viable and dead pups.

All pups were culled on PND4.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals [describe when, e.g. as soon as possible after the last litters in each generation were produced.]
- Maternal animals: All surviving animals [describe when, e.g. after the last litter of each generation was weaned.]

GROSS NECROPSY
- Gross necropsy consisted of [external and internal examinations including the cervical, thoracic, and abdominal viscera.]

HISTOPATHOLOGY / ORGAN WEIGHTS
The tissues indicated in Table [#] were prepared for microscopic examination and weighed, respectively.

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring not selected as parental animals and all F2 offspring were sacrificed at [#?] days of age.
- These animals were subjected to postmortem examinations (macroscopic and/or microscopic examination) as follows:

GROSS NECROPSY
- Gross necropsy consisted of [external and internal examinations including the cervical, thoracic, and abdominal viscera.]

HISTOPATHOLOGY / ORGAN WEIGTHS
The tissues indicated in Table [#] were prepared for microscopic examination and weighed, respectively.

Statistics:

Data were recorded on the appropriate forms from the relevant SOPs of CiToxLAB Hungary Ltd., and then tabulated using the Microsoft Office Word and/or Excel, or using the software PROVANTIS, as appropriate. Numerical data obtained during the conduct of the study were subjected as appropriate to calculation of group means and standard deviations.

The statistical evaluation of appropriate data (marked † below) was performed with the statistical program package SPSS PC+4.0 (SPSS Hungary Kft, Budapest). The homogeneity of variance between groups was checked by Bartlett’s homogeneity of variance test. Where no significant heterogeneity wasdetected, a one-way analysis of variance (ANOVA) was carried out. If the obtained result was significant, Duncan Multiple Range test was used to access the significance of inter-group differences. For a significant result at Bartlett’s test, the Kruskal-Wallis analysis of variance was used and the inter-group comparisons were performed using Mann-Whitney U-test. Chi2 test was performed as feasible.

Reproductive indices:

Parental Males:
Number of pairings, number of fertile pairings, number of infertile males, male mating index, male fertility index.

Parental Females:
Number of pairings, number of pregnant females, number of sperm positive, but non-pregnant females, number of non mated females, female matingindex, female fertility index, gestation index, duration of pregnancy (days), number of corpora lutea/dams, number of implantations/ dams, number of dams with live pups Day 0 and 4, pre-implantation mortality, intrauterine mortality, total mortality (intra and extra uterine mortality).

Offspring viability indices:

- Mean pup body weight (per pup within the group and per litter) on PND 0 and 4
- Mean pup body weight gain (per litter) between postnatal Days 0-4
- Number of live births per litter, and number of viable pups per litter on postnatal Days 0 and 4
- Survival Index of pups on postnatal Days 0 and 4
- F*sex ratio % (on postnatal Days 0 and 4)

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

In clinical chemistry analysis, the albumin concentration was higher than the control in both sexes (by ~11% at the high dose). Consequently, total protein concentration was also higher and attained statistical significance in both high dose male and female treated groups. These changes could be associated with the organ weight changes and the microscopic liver findings

Urinalysis findings:

no effects observed

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

There were no toxicologically significant changes in animal behaviour, general physical condition or in the reactions to different type of stimuli in the control or test groups. There was no effect of treatment noted during the assessment of foot splay, grip strength or motor activity. The total travelled distance in the test groups was comparable to the control groups for both sexes.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Test item related microscopic findings were noted in the liver and kidney at dose levels of 125 and 500 mg/kg bw/day. These microscopic changes correlated with increased liver and kidney weights related brain weights.

Histopathological findings: neoplastic:

not examined

Other effects:

no effects observed

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Details on results (P0)

There were no differences between the control and test item treated groups with regard to reproductive ability, mating or gestation indices, and no effects considered adverse or toxicologically significant in correlation with RCX 14-672 administration. The mating indices were 100% in all groups and the fertility index was 100, 92, 92 and 100% in control, low, mid and high dose groups, respectively. The gestation index was 100% in all groups.

One high dose female suddenly died during the gavage procedure on Day 35. Pathological changes in the lungs indicated that misdosing caused the death for this female. No test item related adverse effects or systemic clinical signs were noted during the study. There were no toxicologically significant changes in animal behaviour, general physical condition or in the reactions to different type of stimuli in the control or test groups.

No test item related macroscopic findings were observed. Test item related microscopic findings were noted in the liver and kidney at dose levels
of 125 and 500 mg/kg bw/day. These microscopic changes correlated with increased liver and kidney weights related brain weights.

Test item administration was considered to have no impact on the duration of the mating period. Successful coitus (sperm positive vaginal smears and/or vaginal plugs) generally occurred within up to 5 days of pairing (cohabitation). In one high dose female (4505), the duration of the mating period was 13 days, with almost continuous dioestrus observed during the oestrus cycle, however this female successfully paired on Day 13. This variation was regarded as individual, normal biological variability and without toxicological significance. Mean pre-coital interval was 2.4, 2.1, 3.7 and 3.4 days in control, low, mid and high dose groups, respectively.

There was no effect of treatment noted during gestation, parturition or the post-partal period. The mean duration of pregnancy was comparable in the control and test item treated groups. There was one control dam (1512) with abnormal parturition on GD 24; all other parturitions were normal. The number of corpora lutea and number of implantation sites was comparable to the control mean at all dose groups. No test item-related microscopic changes were noted in the reproductive organs at a dose level of 500 mg/kg bw/day. There were no significant differences or effects that could be ascribed to treatment on the pre-implantation, post-natal or total mortality values (litter mean and %) at up to and including 500 mg/kg bw/day.

Effect levels (P0)

1

Key result

Dose descriptor:

NOAEL

Effect level:

31.25 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no effects observed

2

Key result

Dose descriptor:

LOAEL

Effect level:

125 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

organ weights and organ / body weight ratios

histopathology: non-neoplastic

3

Key result

Dose descriptor:

dose level: 500 mg/kg bw

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical biochemistry

organ weights and organ / body weight ratios

histopathology: non-neoplastic

Target system / organ toxicity (P0)

1

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

125 mg/kg bw/day (nominal)

System:

hepatobiliary

Organ:

liver

Treatment related:

yes

Dose response relationship:

yes

Relevant for humans:

not specified

2

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

125 mg/kg bw/day (nominal)

System:

urinary

Organ:

kidney

Treatment related:

yes

Dose response relationship:

no

Relevant for humans:

not specified

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality / viability:

no mortality observed

Description (incidence and severity):

The number of viable pups on PND4 as well as pups survival indices on PND0 and PND4 were comparable to control values at up to and including 500 mg/kg bw/day. Overall, there were not treatment-related effects on pup mortality. There were no treatment related effect on the viability of pups on PND0 and PND 4.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

There were no effects considered adverse on the offspring weight or weight gain following administration of RCX 14-672 at 31.25, 125 or 500 mg/kg bw/day to parental generation under the conditions of this study. When evaluated per litter basis, the mean litter body weights and/or body weight gain on PND 0 and 4 showed no statistically or toxicologically significant differences compared to controls in the F1 generation. There were no effects of treatment on pup weights or weight gains.

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:

no effects observed

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Description (incidence and severity):

Cannibalized (stillborn or live born) pups were incidentally observed in one control female, three low dose female, two mid dose females and three high dose females.

Histopathological findings:

not examined

Other effects:

not examined

Developmental neurotoxicity (F1)

Behaviour (functional findings):

not examined

Developmental immunotoxicity (F1)

Developmental immunotoxicity:

not examined

Details on results (F1)

OFFSPRING (F1) GENERATION

Mortality and clinical observations:
The number of viable pups on PND4 as well as pups survival indices on PND0 and PND4 were comparable to control values at up to and including 500 mg/kg bw/day. Overall, there were not treatment-related effects on pup mortality. There were no treatment related effect on the viability of pups on PND0 and PND 4.

Cannibalized (stillborn or live born) pups were incidentally observed in one control female, three low dose females, two mid dose females and three high dose females.

Body weight and body weight gain:
There were no effects considered adverse on the offspring weight or weight gain following administration of RCX 14-672 at 31.25, 125 or 500 mg/kg bw/day to parental generation under the conditions of this study. When evaluated per litter basis, the mean litter body weights and/or body weight gain on PND 0 and 4 showed no statistically or toxicologically significant differences compared to controls in the F1 generation. There were no effects of treatment on pup weights or weight gains.

In summary, there were no adverse effects on the F1 offspring viability, clinical signs, development or at observations following euthanasia.

Effect levels (F1)

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

> 500 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no effects observed

Overall reproductive toxicity

Key result

Reproductive effects observed:

no

Lowest effective dose / conc.:

500 mg/kg bw/day (nominal)

Treatment related:

no

Applicant's summary and conclusion

Conclusions:

No test item related changes were noted in the reproductive parameters during mating and gestation, delivery and post-partum/lactation period until PPD5. There were no adverse effects on the F1 offspring viability, clinical signs, development or at observations following euthanasia. No test item-related microscopic changes were noted in the reproductive organs.

Under the conditions of this study, the no observed adverse effect level (NOAEL) for RCX 14-672 is considered to be 500 mg/kg bw/day for the F1/pups generation.

Executive summary:

A Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test in the Rats was conducted to obtain information on the toxicity of the test item RCX 14-672. Repeated daily administration of RCX 14-672 by oral gavage to Wistar rats at dose levels of 31.25, 125, or 500 mg/kg bw/day during the treatment period under the conditions of this study did not result in test item related mortality, clinical adverse effects, or changes in neurological assessment, body weight, food consumption, haematology, coagulation or urinalysis parameters.

No test item related changes were noted in the reproductive parameters during mating and gestation, delivery and post-partum/lactation period until PPD5. There were no adverse effects on the F1 offspring viability, clinical signs, development or at observations following euthanasia. No test item-related microscopic changes were noted in the reproductive organs.

In conclusion, under the conditions of this study, the no observed adverse effect level (NOAEL) for RCX 14-672 is considered to be 31.25 mg/kg bw/day for parental/adult generation, and 500 mg/kg bw/day for the F1/pups generation.