N-(2-(4-amino-N-ethyl-m-toluidino)ethyl)methanesulphonamide sesquisulphate

Endpoint summary

Description of key information

Combined 28-Day Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test (according to OECD 422), oral, rat: systemic NOAEL >= 50 mg/kg bw/day (highest dose tested)

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 Nov 2017 - 14 Aug 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted in 2016

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EPA OPPTS 870.3550, Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test

Version / remarks:

adopted in 2000

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Remarks:

Crl: WI(Han)

Details on species / strain selection:

The Wistar Han rat was chosen as the animal model for this study as it is an accepted rodent species for toxicity testing by regulatory agencies. The laboratory has general and reproduction/developmental historical data in this species from the same strain and source.

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany
- Females nulliparous and non-pregnant: yes
- Age at study initiation: males approx. 10 weeks, females approx. 13 weeks
- Weight at study initiation: males 266-299 g, females 191-242 g
- Fasting period before study: no
- Housing: On arrival and until mating animals were group housed (up to 5 animals of the same sex and same dosing group together) in polycarbonate cages (Macrolon, MIV type, height 18 cm). During the mating phase, males and females were cohabitated on a 1:1 basis in Macrolon plastic cages (MIII type, height 18 cm). During the post-mating phase, males were housed in their home cage (Macrolon plastic cages, MIV type, height 18 cm) with a maximum of 5 males/cage. During pregancy and lactation females were individually housed in Macrolon plastic cages (MIII type, height 18 cm). Pups were housed with the dam, except during locomotor activity monitoring of the dams.
- Diet: pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany), ad libitum
- Water: municipal tap water via water bottles, ad libitum
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-22
- Humidity (%): 43-54
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES (main study): From: 23 Jan 2018 To: 20 Mar 2018

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Test item dosing formulations (w/w) were homogenized to visually acceptable levels at appropriate concentrations to meet dose level requirements.The dosing formulations were prepared weekly as a solution, filled out in daily portions and stored in the refrigerator protected from light. The dosing formulations were removed from the refrigerator and stirred at room temperature for at least 30 minutes before dosing.

VEHICLE
- Concentration in vehicle: 1.67, 5 and 16.7 mg/mL
- Amount of vehicle: 3 mL/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Dose formulation samples were collected at one occasion during the study (week 1). Analyses were performed using a validated UPLC analytical procedure. Concentration analysis was performed for all groups and homogeneity analysis was performed for the low and high dose group.
Concentration results were considered acceptable if mean sample concentration results were within or equal to ± 10% for solutions of target concentration. Homogeneity results were considered acceptable if the coefficient of variation (CV) of concentrations was ≤ 10%.

Stability analyses performed previously in conjunction with the method development and validation study demonstrated that the test item is stable in the vehicle when prepared and stored under the same conditions at concentrations bracketing those used in the present study.

The concentrations analysed in the formulations of all test item groups were in agreement with target concentrations (i.e. mean accuracies between 90% and 110%). No test item was detected in the vehicle control formulation. The formulations of the low and high dose groups were homogeneous (i.e. coefficient of variation ≤ 10%).

Duration of treatment / exposure:

Males were treated for 29 days up to and including the day before scheduled necropsy. This included a minimum of 14 days prior to mating and during the mating period.
Females that delivered were treated for 50 to 56 days, i.e. 14 days prior to mating, the variable time to conception, the duration of pregnancy and at least 14 days after delivery, up to and including the day before scheduled necropsy.
One mid dose female which failed to deliver was treated for 41 days.

Frequency of treatment:

daily, 7 days/week

Dose / conc.:

5 mg/kg bw/day (actual dose received)

Dose / conc.:

15 mg/kg bw/day (actual dose received)

Dose / conc.:

50 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dose levels were selected based on the results of a 10-day dose range finder with oral administration of the test item in rats, and in an attempt to produce graded responses to the test item. In this range finding study, dose levels of 75 and 150 mg/kg bw/day were tested to three female rats/dose. At 150 mg/kg bw/day, all females were sacrificed in extremis on Day 3. At 75 mg/kg bw/day, clinical signs were noted consisting of hunched posture and piloerection and more incidentally abnormal gait, lethargy and/or shallow respiration, one female showed body weight loss (4%) on Day 5 and displayed gray-white foci on the heart; and liver and kidney weight were considered increased.

Positive control:

no

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least twice daily; during the dosing period, observations were performed at 0-15 min and 1 hour (±15 min) after dosing (based on the peak effect of occurrence of clinical signs observed in the dose range finder).

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once weekly at 1 hour (±15 min) after dosing

FUNCTIONAL TESTS: Yes
- Time schedule: males during week 4; females during the last week of lactation
- How many animals: 5 selected males and femles/group
- Parameters examined: hearing ability, pupillary reflex, static righting reflex, fore- and hind-limb grip strength, locomotor activity

BODY WEIGHT: Yes
- Time schedule for examinations: on the first day of treatment and weekly thereafter; mated females were weighed on Days 0, 4, 7, 11, 14, 17, and 20 post-coitum and during lactation on PND 1, 4, 7, and 13

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
Food consumption was quantitatively measured weekly, except for males and females which were housed together for mating and for females without evidence of mating. Food consumption of mated females was measured on Days 0, 4, 7, 11, 14, 17, and 20 post-coitum and during lactation on PND 1, 4, 7, and 13.

WATER CONSUMPTION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: prior to scheduled necropsy
- Anaesthetic used for blood collection: Yes (isoflurane)
- Animals fasted: males: yes, overnight with a maximum of 24 h, females: no
- How many animals: 5 males and 5 females/group
- Parameters examined: white blood cells (WBC), neutrophils (absolute), lymphocytes (absolute), monocytes (absolute), eosinophils (absolute), basophils (absolute), red blood cells (RBC), reticulocytes (absolute), red blood cell distribution width (RDW), haemoglobin, haematocrit, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), platelets, prothrombin time (PT), activated partial thromboplastin time (APTT)

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: prior to scheduled necropsy
- Animals fasted: males: yes, overnight with a maximum of 24 h, females: no
- How many animals: 5 males and 5 females/group
- Parameters examined: alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), alkaline phosphatase (ALP), total protein, albumin, total bilirubin, bile acids, urea, creatinine, glucose, cholesterol, sodium, potassium, chloride, calcium, inorganic phosphate (Inorg. Phos)

THYROID HORMONES: Yes
- Time schedule for collection of blood: prior to scheduled necropsy
- How many animals: all parental males
- Parameters examined: total thyroxine (T4)

Sacrifice and pathology:

SACRIFICE
- Male animals: All animals following the mating period (a minimum of 28 days of administration)
- Maternal animals which delivered: PND 14-16
- Maternal animals which did not deliver: post-coitum day 25

GROSS NECROPSY
- All animals were subjected to a full post mortem examination, with special attention being paid to the reproductive organs; the numbers of former implantation sites were recorded for all paired females.

ORGAN WEIGHTS
- Organ weights recorded for 5 males and 5 females/group: brain, cervix, epididymis, adrenal gland, coagulation gland together with seminal vesicle, prostate, parathyroid weighed together with thyroid, prostate, heart, kidney, liver, ovaries, spleen, testes, thymus, uterus
- Organ weights recorded for all remaining animals: epididymis, coagulation gland together with seminal vesicle, prostate, parathyroid weighed together with thyroid, testes

HISTOPATHOLOGY
- for 5 males and 5 females/group: bone marrow, bone (femur, sternum), brain (seven levels), cervix, epididymides, eye, adrenal, coagulation gland, mammary gland, parathyroid, pituitary, prostate, seminal vesicle, thyroid, gross lesions/masses, gut-associated lymphoid tissue, heart, kidney, large intestine (cecum, colon, rectum), liver, lung, lymph node (mandibular and mesenteric site), skeletal muscle, sciatic nerve, ovaries, small intestine (duodenum, ileum, jejunum), spinal cord, spleen, stomach, testes, thymus, trachea, urinary bladder, uterus, vagina
- for all remaining animals: cervix, epididymides, coagulation gland, mammary gland, parathyroid, pituitary, prostate, seminal vesicle, thyroid, gross lesions/masses, ovaries, testes, uterus, vagina

SPERM PARAMETERS
- for 5 parental males in the vehicle control and high dose group and one mid dose male that failed to sire:
detailed qualitative testes examination, taking into account the tubular stages of the spermatogenic cycle

Statistics:

All statistical tests were conducted at the 5% significance level. All pairwise comparisons were conducted using two sided tests and were reported at the 1% or 5% levels. Numerical data collected on scheduled occasions for the listed variables were analyzed as indicated according to sex and occasion. Descriptive statistics number, mean and standard deviation (or %CV or SE when deemed appropriate) were reported whenever possible. Inferential statistics were performed according to the matrix below when possible, butexcluded semi-quantitative data, and any group with less than 3 observations.

The following pairwise comparisons were made:
Low dose vs. vehicle control
Mid dose vs. vehicle control
High dose vs. vehicle control

Parametric: Datasets with at least 3 groups (the designated control group and 2 other groups) were compared using Dunnett-test (many-to-one-t-test).
Non-Parametric: Datasets with at least 3 groups was compared using a Steel-test (many-to-one rank test).
Incidence: An overall Fisher’s exact test was used to compare all groups at the 5% significance level. The above pairwise comparisons were conducted using Fisher’s exact test whenever the overall test is significant.

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Blue discolouration of the urine was recorded for most mid and high dose females during the last week of their scheduled treatment period. This finding occurred in the absence of adverse renal pathology. It is conceivable that the bluish discolouration had occurred due to presence of the test item and/or its metabolite(-s) in the urine resulting in a specific light diffraction.

One high dose female showed restless behaviour on the day preceding scheduled necropsy. This restless behaviour was considered not test item-related since none of the other animals at this dose showed similar signs.

No treatment-related clinical signs were noted during weekly arena observations.

Any other clinical signs noted during the treatment period occurred within the range of background findings to be expected for rats of this age and strain and did not show any apparent dose-related trend. At the incidence observed, these were considered to be unrelated to treatment.

Mortality:

no mortality observed

Description (incidence):

No mortality occurred during the study period.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Females: In the high dose, reduced mean weight gain or slight weight loss (up to 4% of the body weight on Day 1 of treatment) was recorded for females during the premating and mating period, being statistically significant only on Day 1 of the mating period. A slightly lower mean weight gain was also recorded for high dose females over Days 4-7 and 7-13 of lactation (4% vs. 8% in the control group over Days 1-7 of lactation, and 7% vs. 12% in the control group over Days 1-13 of lactation; not statistically significant). Mean body weights and weight gain during the postcoitum phase were considered not affected by treatment.
One high dose female showed a lower weight gain during the post-coitum phase. This same female had a lower litter size (5 pups). Since none of the other animals at this dose showed a similar change in body weight, this was considered not related to treatment with the test item.

These body weight variations were not accompanied by treatment-related changes in food intake, and clinically rats appeared in a healthy state. These variations were therefore considered not to be adverse, but the slightly lower body weights at the end of lactation may have resulted in lower pup body weights.

The statistically significantly lower mean body weight of low dose females on Day 8 of the premating period occurred in the absence of a dose related trend, and was therefore considered not to be related to treatment.

Males: Body weights and body weight gain of males remained in the same range as controls over the treatment period.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

One high dose female showed a reduced food intake before and after correction for body weight during lactation. Since none of the other animals at this dose showed a similar change in food intake, this was considered unrelated to treatment with the test item.

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

At the high dose, higher platelet counts were recorded for females (19% higher than control mean). However, these were not supported by other findings and the mean remained within the historical control data range. This finding was therefore considered not to be an adverse change.
Other haematological and coagulation parameters of treated rats were considered not to have been affected by treatment.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

At the high dose, a higher aspartate aminotransferase activity (ASAT) was recorded for females (factor 3 higher than control mean). The mean exceeded the historical control data range. No morphological correlate was noted and therefore, the finding was considered an adaptive rather than an adverse finding.
Other clinical biochemistry parameters of treated rats were considered not to have been affected by treatment.

Thyroid hormone analyses:
Serum levels of T4 in F0 males were not affected by treatment.
The statistically significantly lower T4 of low dose males was considered not to be related to treatment as this occurred in the absence of a dose-related trend.

Urinalysis findings:

not examined

Behaviour (functional findings):

effects observed, treatment-related

Description (incidence and severity):

In the high dose group, a lower mean motor activity (both total movements and ambulations) was recorded for males and females (mean total movements 26% and 46% lower than control means for males and females, respectively; not statistically significant, for details please refer to Table 1). Means remained within the historical control data range. For high dose females, the mean was predominantly affected by one low value for one animal. When this value is not included in the mean, the mean is 2851 counts (i.e. 37% lower than the control mean).
This lower motor activity was not supported by concurrent changes in grip strength measurements or clinical observations, and means remained within the historical control data range for rats of this age and strain. Histopathologically, there were no supportive morphological correlates in examined neuronal tissues. An increase in incidence and severity of myofiber degeneration and mononuclear cell infiltrate (up to slight degree) of the skeletal muscle was observed in females of the high dose group. However, there was no apparent correlation between this skeletal muscle degeneration and the measured lower motor activity on an individual animal basis. Overall, there were no indications that these findings represented an adverse effect on neurobehaviour or were detrimental to motion function or vitality of the animals. As such, these findings were considered not to be adverse.

All groups showed a similar motor activity habituation profile with a decreasing trend in activity over the duration of the test period.
Hearing ability, pupillary reflex and static righting reflex were normal in all examined animals. Grip strength was similar between control and high dose animals.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Test item-related higher liver weights (relative to body weights) were noted in high dose males and females (for details please fefer to Table 2). These higher weights were not supported by histopathological or clinical biochemistry changes and means remained within the historical control data range. As such, this higher liver weight may represent an adaptive change to treatment and was considered not to represent an adverse effect.

Any other differences in organ weights were considered not to be test item-related due to the direction of the change, lack of dose-related pattern, and/or general overlap and variability in individual values.

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no test item-related gross observations. All of the recorded macroscopic findings were within the range of background gross observations encountered in rats of this age and strain.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Test item-related microscopic findings were noted in the kidneys of males and skeletal muscles of females of the high dose group.

A subtle exacerbation of the incidence and severity of the background finding hyaline droplet accumulation of the kidneys (up to moderate) was observed in high dose males (for details refer to Table 3). These hyaline droplets are considered to represent alpha2μglobulin, a normal protein in male rats and in absence of any other test item related signs of kidney pathology considered as non-adverse.

An increased incidence and severity of myofiber degeneration and mononuclear cell infiltrate (up to slight degree) of the skeletal muscle was observed in high dose females (for details please refer to Table 4). These changes of the skeletal muscle were multifocal (scattered) present in most of the high dose females, while in general the skeletal muscles were focally affected in the few female rats of the other dose groups.

The remainder of the recorded microscopic findings were within the range of background pathology encountered in rats of this age and strain. There was no test item-related alteration in the prevalence, severity, or histologic character of those incidental tissue alterations.

Reproductive performance: There was 1/10 couples of the mid dose group with a non-pregnant female. No abnormalities were seen in the reproductive organs, which could account for their lack of fertility.
There were no morphological findings in the reproductive organs of either sex which could be attributed to the test item and stage aware evaluation of the testes did not show any indication for abnormal spermatogenesis.

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Description (incidence and severity):

No effects were noted on sperm measures.

Key result

Dose descriptor:

NOAEL

Effect level:

>= 50 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no adverse effects noted up to and including the high dose of 50 mg/kg bw/day

Critical effects observed:

no

Table 1. Motor activity test summary

Dose level (mg/kg bw/day)	0	5	15	50
	Males
Total movements
Mean	3580	3596	3672	2661
St. Dev.	1212	304	948	892
N	5	5	5	5
Abulations
Mean	696	791	756	550
St. Dev.	378	121	224	210
N	5	5	5	5
	Females
Total movements
Mean	4499	3569	4216	2440
St. Dev.	1397	1004	1122	1008
N	5	5	5	5
Abulations
Mean	1072	851	974	512
St. Dev.	327	211	209	258
N	5	5	5	5

 

Table 2. Mean percent liver weights differences from control groups

		Males			Females
Dose level (mg/kg/day):	5	15	50	5	15	50
LIVER
Absolute	5	4	8	0	5	11
Relative to body weight	2	1	8*	-2	0	11*

* P < 0.05

Table 3. Summary Test Item-Related Microscopic Findings Kidneys

Dose level (mg/kg/day):KIDNEYS^a Hyaline droplet accumulation Minimal Slight Moderate			Males
	0	5	15	50
	5	5	5	5
	2	-	1	-
	-	-	1	2
	-	-	-	1

a  = Number of tissues examined from each group

Table 4. Summary Test Item-Related Microscopic Findings Skeletal Muscle

	Females
Dose level (mg/kg bw/day)	0	5	15	50
Skeletal muscle^a	5	5	5	5
Myofiber degeneration
Minimal	-	2f	1f	1mf
Slight	-	-	-	3mf
Mononuclear cell infiltrate
Minimal	2f	1f	1f	1mf
Slight	-	-	-	3 mf

a=Number of tissues examined from each group

f=focal, mf=multifocal

Conclusions:

In the present study, the NOAEL with respect to general systemic toxicity were set at 50 mg/kg bw/day, the highest dose level tested. It should be noted that this high dose was selected based on severe toxicity observed at 75 and 150 mg/kg bw/day in the 10-day range finding study.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

50 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

The available information comprises an adequate, reliable (Klimisch 1) and consistent study, and is thus sufficient to fulfil the standard information requirements set out in Annex VIII, 8.6, of Regulation (EC) No. 1907/2006.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Repeated dose toxicity: oral

A reliable oral Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test withN-(2-(4-amino-N-ethyl-m-toluidino)ethyl)methanesulphonamide sesquisulphate (CAS 25646-71-3) is available and was performed according to OECD 422 (van Otterdijk, 2018) and in compliance with GLP. Groups of 10 male and 10 female Wistar rats were exposed to the test substance at dose levels of 5, 15 and 50 mg/kg bw/day by oral gavage once daily for 7 days/week for at least 29 (males) and 50-56 (pregnant females) consecutive days. Control animals (10 per sex and dose) received the concurrent vehicle, water, only. Dose levels in this study were based on the results of a dose range finding study. In this range finding study, rats received 75 and 150 mg/kg bw by daily oral gavage up to 10 days. At 150 mg/kg bw, all females were sacrificed in extremis on Day 3. At 75 mg/kg bw, various clinical signs were noted, at necropsy, one female showed several gray-white foci on the heart with slight weight loss, and mean liver and kidney weight was increased.

Observations and examinations of the animals in the current study included clinical signs, functional observations (for 5 selected animals/sex/group), body weight, food consumption, estrous cycle determination, haematology (for 5 selected animals/sex/group), clinical chemistry (for 5 selected animals/sex/group), measurement of thyroid hormone T4 (parental males), gross necropsy, organ weights and histopathology.

Blue discolouration of the urine was recorded for most mid and high dose females during the last week of their scheduled treatment period. This finding occurred in the absence of adverse renal pathology. It is conceivable that the bluish discolouration had occurred due to presence of the test item and/or its metabolite(s) in the urine resulting in a specific light diffraction. Further in-life findings were confined to a slightly lower mean weight gain or slight weight loss (up to 4% of the body weight on Day 1 of treatment) for high dose females during the premating period and during the last week of lactation. These variations were not accompanied by treatment-related changes in food intake, and clinically rats appeared in a healthy state. These body weight variations were therefore considered not to be adverse. At the high dose, a lower mean motor activity was recorded for both sexes, being 26% and 46% lower than control means for males and females, respectively. Upon excluding one low value for high dose females, the mean was 37% lower than the control mean. This lower motor activity was not supported by concurrent changes in grip strength measurements or clinical observations, and means remained within the historical control data range for rats of this age and strain. Histopathologically, there were no supportive morphological correlates in examined neuronal tissues. An increase in incidence and severity of myofiber degeneration and mononuclear cell infiltrate (up to slight degree) of the skeletal muscle was observed in females of the high dose group. However, there was no apparent correlation between this skeletal muscle degeneration and the measured lower motor activity on an individual animal basis. Also, no apparent correlation was present between the factor 3 higher aspartate aminotransferase activity (a non-specific hallmark for muscle damage) recorded for high dose females and muscle fiber degeneration. Overall, there were no indications that these findings represented an adverse effect on neurobehaviour or were detrimental to motion function or vitality of the animals. As such, these findings were considered not to be adverse.

Higher platelet counts were recorded for high dose females, (19% higher than control mean), but these were not supported by other findings and the mean remained within the historical control data range. This was therefore considered not to be an adverse change. An increased incidence and severity of hyaline droplet accumulation of the kidneys was observed in high dose males (up to moderate). These hyaline droplets are considered to represent alpha2µglobulin, a normal protein in male rats and in absence of any other test item related hallmark of kidney pathology considered as non-adverse. Higher liver weights (relative to body weights) in the high dose groups (approximately 10% higher than control means) were not supported by histopathological or clinical biochemistry changes and means remained within the historical control data range. As such, this higher liver weight may represent an adaptive change to treatment and was considered not to represent an adverse effect.

No treatment-related changes were noted in any of the remaining parameters investigated in this study (i.e. other functional observations, food consumption, male T4 thyroid hormone levels and macroscopic examination). In the absence of systemic toxicity, a NOAEL of ≥50 mg/kg bw/day was derived.

Justification for classification or non-classification

The available data on repeated dose toxicity of the test item do not meet the criteria for classification according to Regulation (EC) 1272/2008, and are therefore conclusive but not sufficient for classification.