Benzenesulfonic acid, 4-(acetylamino)-2-amino-5-[2-[3-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-, sodium salt (1:2)

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

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

Adequacy of study:

key study

Study period:

25 January 2011 to 22 March 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to OECD test guidance in compliance with GLP and reported with a valid GLP certificate.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Structural Analogue 01

IUPAC Name:

Structural Analogue 01

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

see below

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Species and strain: Wistar RJHan:WI rats
Source: Laboratoire Elevage Janvier, B.P. 4105, Route des Chênes Secs, 53940 Le Genest-St-Isle CEDEX France
Hygienic level: SPF at arrival; standard laboratory conditions during the study
Justification of species/strain: The rat is regarded as suitable species for toxicology and reproduction studies. Wistar rat was selected due to experience with this strain of rat in toxicity and reproduction toxicity studies and known fertility.
Number of animals: Main groups: 48 male, 48 female rats, 12 animals/sex/group, 4 groups; a sufficient number of at least 8 pregnant females/group was achieved. Recovery groups: 10 male, 10 female rats, 5 animals/sex/group, 2 groups, Control and High dose. Positive Control MNT group: 12 male and 12 female rats, 1 group. At the completion of the study, the spare animals were returned to LAB Research Ltd. spare colony, as their use was not required (no replacements with spare animals were performed).
Age of animals: Young adult rats, approximately 11-12 weeks old at starting and 13-14 weeks at mating. The age range within the study was kept to the minimum practicable.
Body weight range: Males: 397 g – 463 g, Females: 229 g- 273 g; did not exceed ± 20% of the mean weight for each sex at onset of treatment
Acclimation period: At least 7 days (7 days from animal arrival to pre-treatment ophthalmoscopy examination, 12 days to onset of treatment)

Husbandry

Animal health: Only healthy animals were used for the test, as certified by the veterinarian. Females were nulliparous and non-pregnant.
Room number: 524
Cage type: Type II and/or III polypropylene/polycarbonate
Bedding: Lignocel® Hygienic Animal Bedding produced by J. Rettenmaier & Söhne GmbH+Co.KG (Holzmühle 1, D-73494 Rosenberg, Germany). Details of bedding quality are reported.
Light: 12 hours daily, from 6.00 a.m. to 6.00 p.m.
Temperature: 19.6-23.6°C
Relative humidity: 31 - 62%
Ventilation: 15-20 air exchanges/hour
Housing/Enrichment: Rodents were group-housed, up to 5 animals of the same sex and dose group/cage, with the exception of the mating and gestation/delivery period, when they were paired or individually housed, respectively. Group housing allowed social interaction and the deep wood sawdust bedding allowed digging and other normal rodent activities (i.e. nesting).
The temperature and humidity were measured twice daily; no deviations from the target ranges were noted during the study.

Food and water supply

Animals received ssniff® SM R/M-Z+H "Autoclavable complete feed for rats and mice – breeding and Maintenance" produced by ssniff Spezialdiäten GmbH, D-59494 Soest Germany ad libitum, and tap water from municipal supply, as for human consumption from 500 ml bottle ad libitum.

Water quality control analysis is performed once every three months and microbiological assessment is performed monthly by Veszprém County Institute of State Public Health and Medical Officer Service (ÁNTSZ, H-8201 Veszprém, József A.u.36., Hungary).

The food and water are considered not to contain any contaminants that could reasonably be expected to affect the purpose or integrity of the study.
Animal identification

Each parental animal (P Generation) was identified by a number unique within the study, written with indelible ink on the tail and cross-referenced to the Animal Master File at LAB Research Ltd. This number consisted of 4 digits, the first digit being the group number, the second, 0 for the males and 5 for the females, and the last 2, the animal number within the group.
The boxes were arranged in such a way that possible effects due to cage placement were minimized and were identified by cards showing the study code, sex, dose group, cage number and individual animal numbers, date of mating and delivery.

The new-borns (Offspring, F1 Generation) were identified by cutting off digit-tips up to one day after birth.

Randomization

All parental (P) male and female animals were sorted according to body weight by computer and divided to weight ranges. An equal number of animals from each weight group was randomly assigned to each dose group to ensure that test animals were as nearly as practicable of a uniform weight. The grouping was controlled by SPSS/PC software according to the actual body weight, verifying the homogeneity/variability between/within the groups and cages. Males and females were randomized separately.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Remarks:

distilled

Details on oral exposure:

The test item was formulated in distilled, sterile water for injection at 6.25, 25 and 100 mg/mL concentrations without correction for purity, in the Central Dispensary of LAB Research Ltd. Formulations were prepared and stored refrigerated at 2-8ºC pending use within 7 days.

Rationale for dose selection and route of administration

The dose levels were selected by the Sponsor in consultation with the Study Director based on available data and information from previous experimental work, including the results of an acute oral toxicity study (LAB study code 10/296-001P) and a repeated dose range finding study in the rat (LAB study code 10/296-220PE), with the aim of inducing toxic effects but ideally no death or suffering at the highest dose and a NOAEL at the lowest dose. The oral route was selected as it is a possible route of exposure to the test item in humans.

Test item or Control (water)-treated Groups 1-4 Main animals were administered the dosing solutions daily on a 7 days/week basis, by oral gavage using a tipped gavage needle attached to a syringe. A constant volume was administered to all animals. The actual volume administered was calculated and adjusted based on each animal’s most recent body weight. Dosing of both sexes began after at least 7 days acclimation (A) and 12 days after the animal arrival; the animals were dosed for 2 weeks before mating, during the mating/post-mating, and were continued up to and including the day of necropsy.

Vehicle:
Name: Distilled, sterile water for injection, PhEUR
Lot No.: 3590210, 7530810, 8490910
Manufacturer: TEVA Pharmaceutical Corporation
Expiry Date: February 2013, August 2013, September 2013 respectively
Storage: Room temperature

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Top, middle and bottom duplicate samples were taken from test item formulations on 3 occasions, during the first and last weeks and approximately midway during the treatment, one set to analyze (which was collected in replicates as practical) and one set as a back-up for any confirmatory analyses. Similarly, one sample was taken in duplicate from the vehicle Control Group 1 solution for concentration measurements.

The samples were evaluated by UV-HPLC method.

The measured concentrations varied between 95% and 103% of the nominal concentrations (6.25, 25 and 100 mg/mL). No test item was detected in the Control solution samples. These results were considered suitable for the study purposes.

Duration of treatment / exposure:

Males were dosed for at least 28 days (14 days pre-mating, 14 days mating/post-mating period and on the day of necropsy).
Females were dosed for 14 days pre-mating, for up to 6 days mating period, through gestation and up to and including the day of necropsy (at least 4 days post-partum dosing). The day of birth (viz. when parturition was complete) is defined as Day 0 post-partum. Females showing no-evidence of copulation were sacrificed as practical, 26-27 days after the end of the mating period.
Additional 5 male and 5 female rats from the Control and High dose Recovery Groups 1 and 4 scheduled for follow-up observations were not mated, but treated up to the first scheduled euthanasia of the Main dams (Day 41).

Frequency of treatment:

Once daily, 7 days per week

Doses / concentrations

Remarks:

Doses / Concentrations:
0 (control), 62.5, 250, 1000 mg/kg bw/day
Basis:
nominal in water

No. of animals per sex per dose:

Main groups: 48 male, 48 female rats, 12 animals/sex/group, 4 groups
Recovery groups: 10 male, 10 female rats, 5 animals/sex/group, 2 groups, Control and High dose

Control animals:

yes, concurrent vehicle

Details on study design:

See below under any other information for details of experimental design.

Examinations

Observations and examinations performed and frequency:

CLINICAL OBSERVATIONS AND FUNCTIONAL OBSERVATION BATTERY (FOB)

All animals: Animals were inspected for signs of morbidity and mortality twice daily, at the beginning and 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 (pm) as practical during the working day, as no peak period of effects was noted after dosing during the first days of treatment. During Recovery period, the animals were similarly observed daily as practical.

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 onset, degree and duration of signs as applicable.

More detailed examinations were made once before the first exposure (to allow for within-subject comparisons), then at least weekly, in the morning (am) or before treatment. These observations were made outside the home cage in a standard arena, at similar 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. No such clinical signs were observed during the study.

Main animals, 5 males and 5 females/group, “subgroup A”:

Assessment of any potential test item related neurotoxicity was performed during the last exposure week (males, on Day 24 am, females, on PND 3 am). In order to avoid hyperthermia of pups, dams were removed from the pups for not more than approximately 30-40 minutes. Selected animal were subjected to the functional observation battery, including qualitative assessment of the grip strength, and to measurements of the landing foot splay and fore/hind grip strength.

To measure the landing foot splay, the fore/hind paws of the rat were painted with ink and the rats were dropped from a horizontal position onto the appropriate record sheet covering the examination table. The distance between the two resulting ink spots was measured.

Fore/hind grip strength measurements were conducted 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 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 with the appropriate grip support; results are tabulated with individual and mean data.

Sensory reactivity to different type of stimuli (e.g. auditory, visual and proprioceptive), assessment of grip strength and motor activity were conducted and the general physical condition and behaviour of animals were tested. A modified Irwin test was performed. Parameters such as, but not limited to 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.

Recovery animals: Neurotoxicity evaluation was similarly conducted in the Recovery animals towards the end of the Recovery period, one day before necropsy (Day 55, for necropsy on Day 56).

BODY WEIGHT MEASUREMENT

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

FOOD CONSUMPTION MEASUREMENT

Animal food consumption was determined by re-weighing the non-consumed diet with a precision of 1 g on Day 7 then at least weekly.

OPHTHALMOLOGY

The fundus of eyes of all animals was examined before treatment. Five male and 5 female Control and High dose animals (“subgroup C”) randomly selected from groups 1 and 4, during the last week of treatment prior to necropsy (males, Day 24 pm, females, PND 3 pm). Mydriasis was produced after instillation of a mydriatic agent (eye drops "Mydrum") into the conjunctival sac. The examination was performed using a Gowlland ophthalmoscope. As no ophthalmoscopic alterations were found, no additional examination was performed in other animals.

CLINICAL PATHOLOGY

All animals selected for blood sampling were fasted (overnight period of food deprivation).

For terminal blood sampling of Recovery animals, 3 samples were taken from each animal: one for haematology (1.2 mL blood, in tubes with K3-EDTA as anticoagulant, 1.6 mg/mL blood), one for blood clotting times (1.4 mL blood for APTT and PT measurements, in tubes with sodium citrate as anticoagulant) and one to obtain serum (approximately 1 mL blood as practical, in tubes with no anticoagulant) for clinical chemistry.

For Day 14 blood sampling of Main animals selected (subgroup B), 2 samples were taken from each scheduled animal: one for haematology (1.2 mL blood, in tubes with K3-EDTA as anticoagulant, 1.6 mg/mL blood) and one to obtain serum (approximately 1 mL blood as practical, in tubes with no anticoagulant) for clinical chemistry. Due to technical problems at use of the VITROS 250 equipment, clinical chemistry results collected on Day 14 as available will be archived with the study file but are not reported. Additional blood samples were collected for clinical chemistry evaluation from the subgroup B Main animals prior to the scheduled necropsy by heart puncture under pentobarbital anaesthesia, into empty tubes with no anticoagulant to obtain serum.

For terminal blood sampling of Main animals selected (subgroup B), 2 samples were taken from each scheduled animal: one to obtain serum (approximately 1 mL blood as practical, in tubes with no anticoagulant) for clinical chemistry and one for blood clotting times (1.4 mL blood for APTT and PT measurements, in tubes with sodium citrate as anticoagulant).

For urine collection, the selected animals (Main subgroup B and Recovery) were placed in metabolic cages for approximately 16 hours and food and water deprived, then water were provided at libitum for at least approximately 2 hours prior to necropsy and organ weight measurements.

Main animals, 5 males and 5 females/group, “subgroup B”:

Laboratory examinations for haematology and clinical chemistry evaluation were conducted at the end of pre-mating period, on blood samples collected from the sublingual vein, prior to the start of mating on Day 14 from 5 animals/sex/group randomly selected (“subgroup B”). Coagulation evaluation (APTT and PT) was performed at the completion of the treatment, on blood samples collected by cardiac puncture from subgroup B animals under pentobarbital anaesthesia, immediately prior to scheduled necropsy.

Urine sampling (approximately 16 hours sampling period) was performed prior to necropsy from the same subgroup B (urinalysis on Day 28-males, PND 5-females).

Recovery animals:

Haematology, coagulation and clinical chemistry investigations were conducted at the completion of the Recovery period, 14 days after the first scheduled euthanasia of Main dams. Blood samples were collected by cardiac puncture under pentobarbital anaesthesia, immediately prior to scheduled necropsy.

Urine sampling (approximately 16 hours sampling period) was performed from the Recovery animals prior to necropsy (urinalysis on the day of necropsy, conducted 14 days after the first scheduled euthanasia of the Main dams).

Haematology and blood clotting times

The parameters evaluated are detailed in a table under any other information on materials and methods below.
Blood smears (red cell morphology) were prepared for all subgroup B Main and all Recovery animals. As no evaluation is considered required with Sponsor’s approval, based on the haematology results, the slides will be archived at LAB Research Ltd. with study specimens. Additional blood samples were collected from all Main animals immediately prior to the scheduled necropsy, by heart puncture under pentobarbital anaesthesia, into empty tubes with no anticoagulant to obtain serum. The serum was stored frozen at approximately - 20°C, then will be discarded prior to finalization of the study report with Sponsor’s approval, as no additional investigations are considered required to prove exposure of the animals to the test item, since dark yellow and/or orange discoloration of the urine collected prior to necropsy from animals placed in metabolic cages was observed.

Clinical chemistry

The parameters evaluated are detailed in a table under any other information on materials and methods below.

Urinalysis

The parameters evaluated are detailed in a table under any other information on materials and methods below.

Sacrifice and pathology:

Pathology

Gross necropsy was performed on all animals. Terminally, after completion of the treatment or Recovery periods as applicable, animals were sacrificed under pentobarbital anaesthesia followed by exsanguination. After exsanguination the external appearance was examined, cranium, thoracic and abdominal cavities were opened and the appearance of the tissues and organs were observed macroscopically. Any abnormality was recorded with details of the location, colour, shape and size, as appropriate. Special attention was paid to the organs of the reproductive system. The number of implantation sites and of corpora lutea was recorded in the Main females as applicable.

At the time of termination, body weight and weight of the following organs of all parental animals were determined:

- With a precision of 0.01 g: uterus (with and without cervix), vagina, testes, epididymides (total and cauda), prostate, seminal vesicles with coagulating glands, brain
- With a precision of 0.001 g: ovaries, pituitary

The weighed organs and all organs showing macroscopic lesions of all adult animals were preserved. The eyes with the optic nerve were retained in modified Davidson’s fixative. Testes and epididymides were preserved in Bouin’s solution, all other organs in 10% buffered formalin solution.

In addition, for 5 animals/sex/group (subgroup B, Main) and for Recovery animals, the following organs and tissues, or representative samples, were preserved:

Gross findings, Liver, Small intestine (8), Adrenals, Lungs with bronchi (5), Spinal cord (cervical, lumbar, and thoracic levels), Animal identification (1), Lymph nodes (6), Aorta, Mammary gland (inguinal), Spleen, Brain (2), Ovaries with oviduct, Sternum with marrow, Epididymides, Pancreas, Stomach, Eyes with optic nerves (7), Pituitary, Testes, Oesophagus, Prostate, Thymus, Femur with marrow , Salivary gland (mandibular), Thyroid with parathyroids (7), Heart (3), Sciatic nerve, Tongue, Kidneys, Seminal vesicles, Trachea (with main stem bronchi), Large intestine (4), Coagulating glands, Urinary bladder, Lacrimal glands, Skeletal muscle (quadriceps), Uterus (9), Harderian glands, Skin and subcutis (inguinal), Vagina.

1. Fixation and preservation only.
2. Cerebral cortex, midbrain, cerebellum and medulla.
3. Section including both ventricles and atria, septum with papillary muscle.
4. Caecum, colon and rectum.
5. Lungs of euthanized animals were infused with formalin.
6. Mandibular and mesenteric.
7. Parathyroids and optic nerves were examined histologically only if present in routine sections.
8. Duodenum, ileum and jejunum with Peyer’s patches.
9. Horns, body and cervix.


From subgroup B Main animals and Recovery animals, the following organs were weighed in addition to the ones previously mentioned:

- With a precision of 0.01 g: heart, kidneys, liver, spleen and thymus
- With a precision of 0.001 g: adrenals.

For all organs, paired organs were weighed individually. Individual and/or paired absolute organ weight are reported for each animal and adjusted for the body and brain weights. Paired organ weights as applicable were summarised. Relative organ weight (to body and brain weight) were calculated and reported.

For the adult animals, detailed histological examination was performed on the selected list of retained organs in the Control and High dose groups (Main and Recovery) and all macroscopic findings (abnormalities) from all animals. As no test item related pathology findings were noted, no additional histopathology evaluation was considered required. Special attention was paid to evaluation of the stages of spermatogenesis in the male gonads and histopathology of interstitial testicular cell structure. Detailed histological examination of the ovaries covered the follicular, luteal, and interstitial compartments of the ovary, as well as the epithelial capsule and ovarian stroma.

The retained tissues and organs were embedded in paraffin wax, sections were cut at 4-6µ by microtome and transferred to slides. Tissue sections were stained with haematoxylin-eosin/phloxine and examined by light microscope.

Statistics:

Data were recorded on the appropriate forms from the relevant SOPs of LAB Research Ltd., and then tabulated using the Microsoft Office Word and/or Excel, 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. The homogeneity of variance between groups was checked by Bartlett’s homogeneity of variance test. Where no significant heterogeneity was detected, 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. Getting 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.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Expected staining effect on urine

Mortality:

mortality observed, treatment-related

Description (incidence):

Expected staining effect on urine

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:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

Expected staining effect on urine

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Test substance colouration

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

MORTALITY

No test item related mortality occurred during the study.
Low dose female 2504 was found dead on Day 39, due to incidentally difficult parturition. Prior to its death, this female displayed no clinical signs between Days 0 and 37 of treatment. On the day of parturition (treatment Day 38), after delivery of 9 live pups, vaginal bleeding, paleness, piloerection, decreased activity and increased respiration were noted, followed by death on PPD1. At necropsy, one foetus was found dead in the uterus of this female, placed in both uterine horns (transversally), which was considered the cause of the difficult parturition followed by bleeding and incidental death. In addition, dark red, non-collapsed lungs, red fluid in the thoracic cavity and dark, as possible post-mortem changes, and orange discoloration in the stomach due to the coloring effect of the test item were noted.

CLINICAL OBSERVATIONS

In the surviving animals, no clinical signs were noted following test item administration under the conditions of this study, or in the Control animals administered 10 mL/kg vehicle (distilled, sterile water for injection).
In the Main animals, it should be mentioned that dark yellow urine was noted at 250 mg/kg bw/day in 5/5 male and 5/5 female Mid dose animals, and orange, or dark orange at 1000 mg/kg bw/day in all High dose Main animals, at urinalysis performed prior to necropsy after the animals were placed overnight in metabolic cages for urine collection. These changes were ascribed to elimination of the test item or its metabolites through urine (urine collection in metabolic cages) and an expected staining effect.

NEUROLOGICAL ASSESSMENT

There were no toxicologically significant changes in the animal behaviour, general physical condition, in the reactions to different type of stimuli, grip strength or motor activity in the control or treated groups, at the evaluation performed towards the end of the treatment or Recovery periods.
Increased vocalization was observed on occasion in the animals throughout all the dose groups when subjected to the modified Irwin test (functional observation battery). However, no treatment-related differences to the Control, or dose, or gender related response, were noted, and this sign was considered to be without toxicological significance and within the normal biological variation with respect to behaviour, reactions to different type of stimuli or manipulations.
No test item related effects or statistically significant variations were observed in the landing foot splay test. When compared to Control, there were no statistically or toxicologically significant differences in the mean grip strength values of the forelimbs or hind limbs in the Main animals when evaluated on Day 24 am (males) or PND 3 am (females). In the Recovery 1000 mg/kg bw/day High dose animals, slightly higher than Control mean grip strength of the forelimbs was observed in the females (24%, p<0.01), however, difference was minor, the mean value was lower than Control in the High dose males, without attaining statistical significance, and these variations were regarded as incidental and not to reflect an adverse or a test item related effect.

OPHTHALMOLOGY

No test item related changes compared to pre-treatment were noted during ophthalmoscopy examination of 5 male and 5 female Control and High dose Main animals during the last week of treatment prior to necropsy (males, Day 24 pm, females, PND 3 pm), thus no additional evaluation was required in other dose groups or Recovery animals.


BODY WEIGHT AND BODY WEIGHT GAIN

No adverse effects considered toxicologically significant were noted on the mean body weight and body weight gain values following daily administration of REACTIVE ORANGE F08-0314 at dose levels of up to and including 1000 mg/kg bw/day, either during the treatment or Recovery periods.
In the Main animals, there were no statistically significant differences to Control. In the Recovery animals, lower mean body weight (-5%, p<0.05) and body weight gain (p<0.05) were noted in the High dose males during the second week of treatment; as no similar observations were recorded in the females, or in the Main animals and this variation occurred with isolated incidence, with no associated adverse effects, it was ascribed to individual variability (i.e. male 4017) with no toxicological significance.

FOOD CONSUMPTION

There were no test item-related differences to Control in the mean daily food consumption in any test-item treated Main or Recovery group (62.5, 250, or 1000 mg/kg bw/day) when compared to the Control.
Minor differences to Control were noted or variations within the group, generally associated with changes in the study schedule including mating, delivery, or fasting before blood collection for clinical pathology evaluation, unrelated to treatment and with no statistical or toxicological significance.

CLINICAL PATHOLOGY

HAEMATOLOGY

No test item related effects, or changes considered toxicologically significant were noted in the haematology parameters evaluated in either Main or Recovery animals.
Variations were noted in a few parameters, on occasion attaining statistical significance, including statistically higher MPV in the Main High dose males, (8%, p<0.05), lower MPV in the Recovery High dose females (-11%, p<0.05), higher MCV (4%, p<0.05) or NE (32%, p<0.05, but -22 % lower in the males) in the Main High dose females. Evaluation of the mean and individual results in comparison with the Control data did not reveal any test-item related cause of the changes noted, and/or no consistent dose or gender-related response was observed. Therefore, these differences observed between the Control and treated groups were considered to be incidental or individual findings, which were not related to treatment, were generally comparable with the expected physiological range or were with no toxicological significance.

CLINICAL CHEMISTRY

In the Main animals evaluated at the completion of the treatment prior to necropsy, an apparent total bilirubin T BIL increase was noted in the 1000 mg/kg bw/day Main High dose males and females (74% and 61%, respectively, p<0.01). This was considered to be related to a possible spectral interference with the analytical method caused by the discolouration of the serum by the test item and not to reflect an adverse effect on the liver function. Although T-BIL was 25% higher than Control in the High dose 1000 mg/kg bw/day Recovery females on Day 56, the difference did not attain statistical significance, was not observed in the males, and was ascribed to individual variability (for example, female 4515) and not a test item related effect.
Other clinical chemistry parameters showed on occasion statistically significant variations, however, there was no dose or gender response or the values were within the physiological ranges. For this reason, these variations were not considered toxicologically significant or related to treatment.

URINALYSIS

Test item administration daily by oral gavage at up to and including 1000 mg/kg bw/day did not result in any test item-related effects considered adverse at urinalysis performed prior to necropsy in either Main or Recovery animals.
In the Main animals, dark yellow urine was noted at 250 mg/kg bw/day in 5/5 male and 5/5 female Mid dose animals, and orange, or dark orange at 1000 mg/kg bw/day in all High dose Main animals (2/5 males and 3/5 females, dark orange, and 3/5 males and 2/5 females, orange), at urinalysis performed prior to necropsy after the animals were placed overnight in metabolic cages for urine collection. These changes were ascribed to elimination of the test item or its metabolites through urine (urine collection in metabolic cages) and an expected staining effect.
The volume of urine and/or urinary pH showed minor variations, on occasion statistically significant, however, with no dose or gender-dependent, and not considered to be of toxicological importance in correlation with test item administration in the conditions of this study. The few other minor variations observed did not attain statistical significance and/or were regarded as normal background changes.

PATHOLOGY EVALUATION

TERMINAL

MAIN (DAY 28 or PND5)

Parental Generation (including subgroup B)

Macroscopic Findings:

Treatment-related macroscopic findings were observed in the stomach, small intestine, cecum, colon and rectum. Dark discoloration red/orange of the stomach, small intestine, cecum, colon and/or rectum was recorded in 13/23, 24/24 and 24/24 surviving adult rats from the Low, Mid and High Dose groups, respectively.

All other macroscopic findings recorded including dark, red discoloration or pale mottling of the lungs or seminal vesicle, spleen enlargement, dilatation of the renal pelvis, or dark red, bilateral discoloration of the cornea were incidental or terminal procedure-related.

Microscopic Findings:

There were no test item-related findings observed histologically in the stomach, small intestine, colon, cecum and rectum and no correlation with the macroscopic findings noted at necropsy was observed.

No evidence of treatment-related histological findings was recorded in the High and Control animals in the reproductive organs. The follicular, luteal and interstitial compartments of the ovary as well as epithelial capsule and stroma were similar histological structure in both Control and High Dose females. Histopathological evaluation of the male gonads as well as testicular interstitial cell structure, the spermatogenic cells representing different phases of the development and differentiation of the spermatozoons were similar in Control and High Dose males.

RECOVERY (DAY 56)

Macroscopic Findings:

The sporadic, macroscopic changes observed both in the male and female rats were incidental or terminal procedure-related.

Microscopic Findings:

There was no evidence of the test item-related microscopic findings. The changes in the kidneys, spleen, pituitary, lungs, liver, uterus and prostate were seen unilaterally and/or with low incidence or severity and were considered to be incidental, or were regarded as terminal procedure-related or incidental.

In summary, a daily oral (gavage) administration of the test item to Wistar RJHan:WI rats was associated with treatment-related dark red/orange discoloration of the stomach, small intestines and/or cecum, colon and/or rectum recorded in 13/23, 24/24 and 24/24 surviving adult rats from the 62.5, 250 and 1000 mg/kg bw/day Mid and High Dose Parental Main rats, respectively. Histologically, no test-item related changes could be observed in the above mentioned organs. Following a 14 day recovery period, no test item-related macroscopic or histological findings were seen at a dose level 1000 mg/kg bw/day in Parental Generation.

ORGAN WEIGHTS

There were no toxicologically significant changes in organ weight values noted after test item administration at up to and including 1000 mg/kg bw/day, evaluated immediately after completion of the treatment, at necropsy on Day 28 (Main males), PND5 (Main females) or after additional 14 days after the first scheduled euthanasia of the dams on Day 41, with necropsy on Day 56 (Recovery male and female animals).

The mean spleen or liver absolute and/or relative weight adjusted for the body or brain weight was slightly higher than control, statistically significant in the Main 250 mg/kg bw/day Mid dose males, or in the Recovery 1000 mg/kg bw/day High dose females (spleen only). In the absence of any dose or gender response, or of any clinical pathology, macroscopic or microscopic changes, these variations were not considered toxicologically significant or related to treatment.

Other absolute organ weights or relative to the body and/or brain weights were similar in the control and test item treated groups, or showed minor variations, ascribed to biological variability (for example vagina weight in the Recovery 1000 mg/kg bw/day High dose females).

Effect levels

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No toxicologically significant effect at highest dose tested (1000 mg/kg bw/day)

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

In summary, the test item administered daily by oral gavage to Wistar rats did not result in test item related mortality or clinical adverse effects at daily, weekly or neurological assessment, in ophthalmological changes, or changes in the body weight, food consumption, haematology, coagulation, clinical chemistry, or urinalysis parameters at dose levels of 62.5, 250, or 1000 mg/kg bw/Day during either the treatment or after a 14-Day Recovery period under the conditions of this study. There were no test item, or effects considered adverse on the reproductive, gestation/parturition or post-partal parameters evaluated.

In the Main animals, dark yellow urine was noted at 250 mg/kg bw/day in 5/5 male and 5/5 female Mid dose animals, and orange, or dark orange at 1000 mg/kg bw/day in all High dose Main animals (2/5 males and 3/5 females, dark orange, and 3/5 males and 2/5 females, orange), at urinalysis performed prior to necropsy after the animals were placed overnight in metabolic cages for urine collection. These changes were ascribed to elimination of the test item or its metabolites through urine (urine collection in metabolic cages) and an expected staining effect.

Treatment-related dark red/orange discoloration of the stomach, small intestines and/or cecum, colon and/or rectum recorded in 13/23, 24/24 and 24/24 surviving adult rats from the 62.5, 250 and 1000 mg/kg bw/day Mid and High Dose Parental Main rats, respectively. Histologically, no test-item related changes could be observed in the above mentioned organs. Following a 14 day recovery period, no test item-related macroscopic or histological findings were seen at a dose level 1000 mg/kg bw/day in Parental Generation.

In conclusion, under the conditions of this study, the no observed adverse effect level (NOAEL) for parental effects is considered to be 1000 mg/kg bw/day.

Executive summary:

The purpose of this Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test in the Rat study was to obtain information on the possible toxic effects of the test item following repeated daily administration by oral gavage to Wistar rats. Reversibility of any treatment-related changes was evaluated following a 14-day Recovery period. The study also comprised a reproductive/developmental toxicity screening test, intended to provide initial information on possible effects on male and female reproductive performance such as gonadal function, mating behaviour, conception, pregnancy, parturition and also on the development of the F1 offspring from conception to Day 4 post-partum. In addition, the test item was evaluated for genotoxic effects by examining the induction of micronuclei in bone marrow erythrocytes of treated and Control animals.

In the Main Groups, male and female Wistar rats were treated for 2 weeks pre-mating, then during the mating/postmating period, males for 28 days and females throughout gestation period and up to and including postnatal/lactation Day PND 5, according to the following Experimental Design:

 

Gr. No.	Group Designation	Dose Level (mg/kg bw/day)	Conc. (mg/mL)	Dose volume (mL/kg bw)	Animal Numbers/ID (Main)
					Male	Female
1	Control	0	0	10	1001-1012	1501-1512
2	Low dose	62.5	6.25		2001-2012	2501-2512
3	Mid dose	250	25		3001-3012	3501-3512
4	High dose	1000	100		4001-4012	4501-4512

 

Additional 5 male and 5 female rats from the Control and High dose Recovery Groups 1 and 4 scheduled for follow-up observations were not mated, but treated up to the first scheduled euthanasia of the Main dams (Day 41), then kept at least for 14 days without treatment to detect delayed occurrence, or persistence of, or recovery from toxic effects, and subjected to necropsy with macroscopic examination on Day 56. 

 

Gr. No.	Group Designation	Dose Level (mg/kg bw/day)	Conc. (mg/mL)	Dose volume (mL/kg bw)	Animal Numbers/ID (Recovery)
					Male	Female
1	Control	0	0	10	1013-1017	1513-1517
4	High dose	1000	100		4013-4017	4513-4517

 

Parameters measured during the study included signs of morbidity and mortality twice daily, daily or detailed weekly observation of clinical signs, neurological and ophthalmoscopic assessment, weekly body weight and food consumption, and clinical pathology evaluation, including haematology, coagulation, clinical chemistry and urinalysis. In addition, the reproductive performance and indices, pregnancy, parturition and post-partal/lactation period were monitored in the adult Main animals, and viability, clinical signs and development were evaluated in their F1 offspring until PND4. At termination, necropsy with macroscopic examination was performed. Weights of selected organs were recorded and representative tissues/organs were sampled and preserved in appropriate fixatives from the adult animals. Histopathology evaluation was conducted on selected tissues and organs retained in fixative and processed to slides from the Control and High dose 1000 mg/kg bw/day animals and on all organs with macroscopic findings from the Low 62.5 mg/kg bw/day and Mid 250 mg/kg bw/day dose groups. In addition, bone marrow smears were prepared at necropsy and evaluation of induction of micronuclei in bone marrow erythrocytes of treated and Control animals was conducted from the Control and High dose Main animals.

 

Analysis of formulations (concentration, homogeneity) and assessment of test item stability in this vehicle in the conditions employed on the study was performed in the Analytical Laboratory of LAB Research Ltd. Stability tests at concentrations from approximately 1 to 100 mg/mL in ultrapure water indicated up to 3 days stability at room temperature and up to 7 days, while stored refrigerated at 2-8ºC, when the recovery range was 93%-101%, which lies within the acceptance range of 100 ± 10%. 

 

Concentration and homogeneity of formulations were evaluated by UV-HPLC method on duplicate samples collected from the top, middle and bottom of test item solutions, and one sample from the control taken and analyzed fresh on 3 occasions during the study. The measured concentrations varied between 95% and 103% of the nominal concentrations (6.25, 25 and 100 mg/mL). No test item was detected in the Control solution samples. These results were considered suitable for the study purposes.  

No test item related mortality or clinical signs were noted.

 

One low dose female was found dead on Day 39, due to incidentally difficult parturition. Prior to its death, this female displayed no clinical signs between Days 0 and 37 of treatment. On the day of parturition (treatment Day 38), after delivery of 9 live pups, vaginal bleeding, paleness, piloerection, decreased activity and increased respiration were noted, followed by death on PPD1. At necropsy, one foetus was found dead in the uterus of this female, placed in both uterine horns (transversally), which was considered the cause of the difficult parturition followed by bleeding and incidental death. In addition, dark red, non-collapsed lungs, red fluid in the thoracic cavity and dark, as possible post-mortem changes, and orange discoloration in the stomach due to the coloring effect of the test item were noted. 

In the surviving animals, there were no clinical signs and all animals were normal at the daily or weekly clinical examinations.

 

There were no toxicologically significant changes in the animal behaviour, general physical condition, in the reactions to different type of stimuli, grip strength or motor activity in the control or treated groups, at the evaluation performed towards the end of the treatment or Recovery periods. Increased vocalization was observed on occasion in the animals throughout all the dose groups when subjected to the modified Irwin test (functional observation battery). However, no treatment-related differences to the Control, or dose, or gender related response, were noted, and this sign was considered to be without toxicological significance and within the normal biological variation with respect to behaviour, reactions to different type of stimuli or manipulations. No test item related effects or statistically significant variations were observed in the landing foot splay test. When compared to Control, there were no statistically or toxicologically significant differences in the mean grip strength values of the forelimbs or hind limbs in the Main animals when evaluated on Day 24 am (males) or PND 3 am (females). In the Recovery 1000 mg/kg bw/day High dose animals, slightly higher than Control mean grip strength of the forelimbs was observed in the females (24%, p<0.01), however, difference was minor, the mean value was lower than Control in the High dose males, without attaining statistical significance, and these variations were regarded as incidental and not to reflect an adverse or a test item related effect.  

On ophthalmoscopy evaluation, there were no test item related changes compared to pre-treatment during ophthalmoscopy examination of 5 male and 5 female Control and High dose Main animals during the last week of treatment prior to necropsy.

 

No adverse effects considered toxicologically significant were noted on the mean body weight and body weight gain values.

 

There were no test item-related differences to Control in the mean daily food consumption in any test-item treatedor Recovery groups.

No test item related adverse effects, or changes considered toxicologically significant were noted in the haematology, coagulation, clinical chemistry or urinalysis parameters evaluated in either Main or Recovery animals. Variations were noted in the mean values of various parameters, on occasion attaining statistical significance, however, they were generally minor and within the historical range, showed no dose and/or gender related response, or were considered incidental or ascribed to individual variability and not related to test item administration.

 

In the Main animals evaluated at the completion of the treatment prior to necropsy, an apparent total bilirubin T‑BIL increase was noted in the 1000 mg/kg bw/day Main High dose males and females (74% and 61%, respectively, p<0.01). This was considered to be related to a possible spectral interference with the analytical method caused by the discolouration of the serum by the test item and not to reflect an adverse effect on the liver function. 

Although T-BIL was 25% higher than Control in the High dose 1000 mg/kg bw/day Recovery females on Day 56, the difference did not attain statistical significance, was not observed in the males, and was ascribed to individual variability (for example, female 4515) and not a test item related effect. 

 

At urinalysis, in the Main animals, dark yellow urine was noted at 250 mg/kg bw/day in 5/5 male and 5/5 female Mid dose animals, and orange, or dark orange at 1000 mg/kg bw/day in all High dose Main animals (2/5 males and 3/5 females, dark orange, and 3/5 males and 2/5 females, orange), at urinalysis performed prior to necropsy after the animals were placed overnight in metabolic cages for urine collection. These changes were ascribed to elimination of the test item or its metabolites through urine (urine collection in metabolic cages) and an expected staining effect. 

On pathology evaluation, a daily oral (gavage) administration of the test item to Wistar RJHan:WI rats was associated with treatment-related dark red/orange discoloration of the stomach, small intestines and/or cecum, colon and/or rectum recorded in 13/23, 24/24 and 24/24 surviving adult rats from the 62.5, 250 and 1000 mg/kg bw/day Mid and High Dose Parental Main rats, respectively. Histologically, no test-item related changes could be observed in the above mentioned organs. Following a 14 day recovery period, no test item-related macroscopic or histological findings were seen at a dose level 1000 mg/kg bw/day in Parental Generation.

There were no toxicologically significant changes in absolute or relative organ weights adjusted for the body or brain weights. Statistically significant, slightly higher spleen, liver or vagina weights were noted on occasion, with no dose or gender response, or any clinical pathology, macroscopic or microscopic changes, and thus, these variations were not considered toxicologically significant or related to treatment.

In conclusion, under the conditions of this study, the no observed adverse effect level (NOAEL) for parental and F1 effects is considered to be 1000 mg/kg bw/day.