2-hydroxy-3-phenoxypropyl acrylate

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 July 2018 - 15 October 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

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)

Version / remarks:

29 July 2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-hydroxy-3-phenoxypropyl acrylate

EC Number:

241-045-8

EC Name:

2-hydroxy-3-phenoxypropyl acrylate

Cas Number:

16969-10-1

Molecular formula:

C12H14O4

IUPAC Name:

2-hydroxy-3-phenoxypropyl acrylate

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: breeder: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: approximately 10 weeks old for males and 11 weeks for females
- Mean body weight: at the beginning of the treatment period, the males had a mean body weight of 409 g (range: 387 g to 430 g) and the females had a mean body weight of 263 g (range: 241 g to 292 g)
- Fasting period before study: no
- Housing: F0 animals were individually housed, except during mating (males + females) and lactation (females + pups), in polycarbonate cages with stainless steel lids and containing autoclaved sawdust. Individual housing of F0 animals was chosen as group housing for pregnant animals can adversely affect gestation and lactation, and to avoid aggressive behaviour around mating
- Diet: SSNIFF R/M-H pelleted diet (free access)
- Water: tap water filtered with a 0.22 µm filter (free access)
- Acclimation period: males were acclimated to the study conditions for 7 days before treatment and females were acclimated to the study conditions for 5 days before the beginning of estrous cycle monitoring during the pre-treatment period
- Parental females selected according to their estrous cyclicity checked before initiation of treatment

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%): 50 ± 20%
- Air changes (per hr): about 8 to 15 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12 h/12 h.

IN-LIFE DATES: 21 August 2018 to 15 October 2018.

Administration / exposure

Route of administration:

oral: gavage

Details on route of administration:

The oral route was selected as it is a route of administration recommended by the Regulatory Authorities for this type of study.
The dose formulations were administered by gavage using a plastic syringe fitted with a plastic gavage tube, once a day, at approximately the same time.

Vehicle:

other:

Remarks:

0.5% (w/v) methylcellulose aqueous solution

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Type of method: High Performance Liquid Chromatography with UV detection (HPLC/UV)
Test item concentrations: the actual test item concentrations in the analyzed dose formulations (i.e. in Weeks 1, 3 and 6) remained within an acceptable range of variation (-3.6% to +9.8%) when compared with the nominal values (nominal concentration ± 15% required).
The dose formulations containing the test item and prepared at 1 mg/mL, 5 mg/mL and 200 mg/mL in 0.5% methylcellulose in water treated by reverse osmosis (w/v) were found to be homogeneous and stable after 14 days (1 mg/mL) and 10 days (5 and 200 mg/mL) at room temperature and protected from light.

Duration of treatment / exposure:

In the males:
- 2 weeks before mating,
- during the mating period (up to 4 days),
- until euthanasia (i.e. after 30 days of treatment),

In the females:
- 2 weeks before mating,
- during the mating period (up to 4 days),
- during gestation,
- during lactation until Day 13 p.p. inclusive,
- until euthanasia for females with no evidence of mating or no delivery.

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

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

Doses / concentrations 2

Dose / conc.:

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

Doses / concentrations 3

Dose / conc.:

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

Doses / concentrations 4

Dose / conc.:

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

No. of animals per sex per dose:

10 animals

Control animals:

yes, concurrent vehicle

Positive control:

no (not required)

Examinations

Observations and examinations performed and frequency:

MORTALITY/MORBIDITY:
- Time schedule: each animal was checked for mortality and morbidity once a day before the treatment period and at least twice a day during the treatment period, including weekends and public holidays.

DETAILED CLINICAL OBSERVATIONS:
- Time schedule: detailed clinical examinations were performed on all animals, once before the beginning of the treatment period and then once a week until the end of the study.

CLINICAL SIGNS:
- Time schedule: from arrival, each animal was observed once a day as part of routine examinations. From the start of the treatment period, each animal was observed once a day, at approximately the same time, for the recording of clinical signs.

BODY WEIGHT:
- Time schedule: the body weight of each male was recorded on the first day of treatment (Day 1), then once a week until euthanasia.
The body weight of each female was recorded on the first day of treatment (Day 1), then once a week until mated (or until euthanasia for the female with no evidence of mating), on Days 0, 7, 14 and 20 post coitum (p.c.) (and on the day of euthanasia for females which did not deliver), and on Days 1, 4, 8 and 13 p.p.
One prematurely euthanized female from group 3 was weighed before euthanasia.

FOOD CONSUMPTION:
- Time schedule: the quantity of food consumed by each male was measured once a week from the first day of treatment until the start of the mating period.
The quantity of food consumed by each female was measured once a week from the first day of treatment until the start of the mating period, during gestation for the intervals Days 0-7, 7-14 and 14-20 p.c. and during lactation for the interval Days 1-4, 4-8 and 8-13 p.p.

During the mating period, food consumption was not measured for males or females.

NEUROBEHAVIOURAL EXAMINATION:
- Time schedule: the first five males and lactating females from each group euthanized as scheduled were evaluated with a Functional Observation Battery once at the end of the treatment period. For females, this was performed on Day 13 p.p. after euthanasia of the pups.
This included a detailed clinical examination, the assessment of reactivity to manipulation and to different stimuli and motor activity.
All animals were observed in the cage, in the hand and in the standard arena.

HAEMATOLOGY:
- Time schedule: the parameters were determined from the first five males and five lactating females from each group euthanized as scheduled, on the day of euthanasia.

COAGULATION:
- Time schedule: the parameters were determined from the first five males and five lactating females from each group euthanized as scheduled, on the day of euthanasia.

CLINICAL CHEMISTRY:
- Time schedule: the parameters were determined from the first five males and five lactating females from each group euthanized as scheduled, on the day of euthanasia.

THYROID HORMONES:
- Time schedule:
* at termination on Day 4 p.p. from at least two culled pups/litter,
* at termination on Day 13 p.p. from at least 2 pups/litter,
* at termination on Day 14 p.p. from all F0 females,
* at termination from all F0 males.
The levels of the thyroid hormone (T4) and thyroid stimulating hormone (TSH) were determined respectively by LC-MS/MS or Luminex MAP® technology for pups sampled on Day 13 p.p. and for F0 males sampled at termination.

Sacrifice and pathology:

SACRIFICE
- Males: after the end of the pairing period (at least 4 weeks of treatment in total),
- Females: on Day 14 p.p.

The following F0 females were euthanized by the same way without overnight fasting:
- females which did not deliver: on Day 26 p.c. (after a body weight recording to check for a possible un-noticed delivery),
- female with no evidence of mating: 25 days after the end of the mating period (after a body weight recording).

ORGAN WEIGHTS: see Tissue Procedure Table below
The body weight of each F0 animal euthanized as scheduled (after the end of the mating period for males or on Day 14 p.p. for females) (including females that did not mate or conceive, and pregnant females that did not deliver) was recorded before euthanasia. For these animals, the organs specified in the Tissue Procedure Table were weighed wet as soon as possible after dissection, or after fixation for thyroids with parathyroids.

GROSS NECROPSY:
A complete macroscopic post-mortem examination was performed on all F0 animals including one prematurely euthanized female (group 3, difficulties to deliver). This included examination of the external surfaces, all orifices, the cranial cavity, the external surfaces of the brain and spinal cord, the thoracic, abdominal and pelvic cavities with their associated organs and tissues and the neck with its associated organs and tissues. Special attention was paid to reproductive organs.
The numbers of corpora lutea and implantation sites were recorded for females euthanized as scheduled on Day 14 p.p. and for two females (one from group 3 and one from group 4) euthanized on Day 26 p.c. due to no delivery.
For apparently 3 non-pregnant females (one from group 1, one from group 2 and one from group 3), the presence of implantation scars on the uterus was checked using the ammonium sulphide staining technique.

PRESERVATION OF TISSUES
The tissues of F0 animals specified in the Tissue Procedure Table were preserved in 10% buffered formalin (except for the eyes with optic nerves and Harderian glands, and the testes and epididymides which were fixed in Modified Davidson's fixative).
Thyroids with parathyroids of the selected pups/litter euthanized on Day 13 p.p. were preserved in 10% buffered formalin.

PREPARATION OF HISTOLOGICAL SLIDES
All tissues required for microscopic examination were trimmed based on the RITA guidelines, when applicable (Ruehl-Fehlert et al., 2003; Kittel et al., 2004; Morawietz et al., 2004), embedded in paraffin wax, sectioned at a thickness of approximately four microns and stained with hematoxylin-eosin (except testes and epididymides which were stained with hematoxylin/PAS).
This tissue processing was performed at Citoxlab France.

HISTOPATHOLOGY:
A microscopic examination was performed on:
- all tissues listed in the Tissue Procedure Table from the first five euthanized as scheduled males and lactating females of the control and high-dose groups (groups 1 and 4),
- all macroscopic lesions of all groups,
- reproductive organs from animals that did not mate or conceive, or from pregnant females that did not deliver, to investigate possible causes i.e. one male and one female (group 1), one male and one female (group 2), two females and one male (group 3), another female (group 3) and one female (group 4).

Special emphasis was paid to the stages of spermatogenesis in the male gonads and histopathology of interstitial testicular cell structure.

Based upon the results of the microscopic examination of the high-dose group, the stomach of the low- and intermediate-dose groups was examined in the first five euthanized as scheduled males and the first five females euthanized on Day 14 p.p.

Statistics:

yes

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Ptyalism was observed mainly in males given 100 mg/kg/day and in some test item-treated females during the premating period. This clinical sign was still observed in some females at 100 mg/kg/day during pregnancy but was no longer noted during the lactation period. This sign, commonly noted when a test item is administered by gavage, was not considered to represent an adverse effect.
At 30 mg/kg/day, piloerection, round back and emaciated appearance were noted in 1/7 females (N23428) on Day 4 p.p. As these clinical signs were not dose-related and/or were most probably due to parturition conditions (this female lost 55 g over the first 4 days of the lactation period), a test item relationship was considered to be unlikely.

All the other clinical signs (i.e. areas of hair loss, cutaneous lesions, scabs, chromodacryorrhea, abnormal growth of teeth, and/or placenta in the bedding) were considered to be unrelated to the test item as they were present in control animals, were not dose-related, were reported sporadically in only a few animals, are commonly observed findings in this species and strain and/or resulted from a logical sequence of parturition.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

There were no unscheduled deaths in males.

In females, there were the following unscheduled deaths:
. At 0 mg/kg/day : Female N23412 was euthanized on Day 26 p.c. for absence of delivery. No remarkable clinical signs were observed prior to euthanasia. A slight body weight loss of 11 g was noted between Days 14 and 20 p.c. At necropsy, no macroscopic post-mortem findings were observed. This female was non-pregnant. At microscopic examination, no relevant changes were observed in the reproductive organs of this female and its corresponding male.
. At 10 mg/kg/day : Female N23417 was euthanized on Day 26 p.c. for absence of delivery. No remarkable clinical signs were observed prior to euthanasia. A slight body weight loss of 7 g was noted between Days 14 and 20 p.c. At necropsy, no macroscopic post-mortem findings were observed. This female was non-pregnant. At microscopic examination, no relevant changes were observed in the reproductive organs of this female and its corresponding male.
. At 30 mg/kg/day : Female N23425 was euthanized on Day 53. This female did not mate and was therefore not pregnant. No remarkable clinical signs were observed prior to euthanasia. At necropsy, no macroscopic post-mortem findings were observed. At microscopic examination, no relevant changes were observed in the reproductive organs of this female. Its corresponding male N23041 had unilateral seminal vesicle and epididymis agenesis, and severe unilateral tubular atrophy/hypoplasia of the testes. These changes unrelated to test item administration, were the likely cause of absence of mating.
Female N23433 was euthanized on Day 26 p.c. for absence of delivery. No remarkable clinical signs were observed prior to euthanasia. A slight body weight loss of 20.8 g was noted between Days 20 and 26 p.c. At necropsy, no macroscopic post-mortem findings were observed. This female was pregnant with 14 implantation sites. At microscopic examination, no relevant changes were observed in the reproductive organs of this female.
Female N23436 was euthanized on Day 24 p.c. due to difficulties to deliver. Signs of poor clinical condition (i.e. pallor of eyes and extremities, piloerection, round back, hypoactivity and abdominal breathing) were observed prior to euthanasia. Eleven live pups and three dead or cannibalized pups were found in the bedding, and 15 implantation scars and one dead fetus were noted in the uterus. The subcutaneous tissue of the thoracic region and the thymus (which was also reduced in size) had a gelatinous appearance, the kidneys, stomach and the wall of intestines showed tan discoloration and/or irregular color, and the periphery of the lungs was whitish. Macroscopic findings observed in kidneys and thymus correlated microscopically with marked necrosis and marked lymphoid atrophy, respectively. In the absence of similar changes in other test item-treated animals, including at the high-dose, these changes are considered to be related to dystocia and stress and not directly test item-related.
. At 100 mg/kg/day: Female N23437 was euthanized on Day 26 p.c. for absence of delivery. Piloerection was observed prior to euthanasia and a body weight loss of 43.8 g was noted between Days 20 and 26 p.c. This female was pregnant with three implantation sites. At necropsy, agenesis of the right kidney, ureter and uterine horn was noted. This was considered as being the likely cause of non delivery. Enlarged corpora lutea were observed in the ovary (considered normal given the ongoing pregnancy).

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

There were no statistically significant differences on mean body weight or mean body weight change at any dose level in males or in females during the premating, gestation and lactation periods.
Lower mean body weight gain was noted in females at 30 or 100 mg/kg/day between Days 1 and 4 p.p. (+2 g and + 6 g, respectively, vs. +17 g in controls, not statistically significant) and then between Days 8 and 13 p.p. in females at 100 mg/kg/day (+9 g vs. +15 g in controls), leading to a lower mean body weight gain at the high-dose level over the whole lactation period (+32 g vs. +43 g in controls).
At 30 mg/kg/day, this effect was mainly due to the body weight loss of female N23428 at parturition and was therefore considered to be incidental.
At 100 mg/kg/day, these differences were considered to be of minor toxicological importance as they were of slight magnitude, isolated and/or with no effects on the mean body weight.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

There were no relevant effects on mean food consumption in males or females at any dose level.
Differences between control and test item-treated animals consisted of slight lower mean food consumption between Days 8 and 15 of the premating period in females at 30 or 100 mg/kg/day (-16% and -12% vs. controls, respectively).
A relationship with the test item was considered to be unlikely as these variations were not dose-related and mainly due to the high value of one control female (43 g/animal/day).

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

There were no statistically significant test item-related effects on hematology parameters at any dose level.
Test item-related differences from controls consisted of low mean neutrophil (-18% and -13% in males and females at 100 mg/kg/day, respectively), eosinophil (-17% and -13% in males and females at 100 mg/kg/day, respectively) and basophil (-20% in males at 30 mg/kg/day and -20% and -33% in males and females at 100 mg/kg/day, respectively) counts, high mean lymphocyte (+16% in females at 100 mg/kg/day) and monocyte (+26% in males at 100 mg/kg/day) counts and/or low mean reticulocyte count (-13% in females at 100 mg/kg/day).
As these variations were of slight magnitude, not statistically significant, within or close to the range of the Historical Control Data, marginal, without any relationship to microscopic findings and/or poorly dose related, they were considered to be of no toxicological importance.

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

At 100 mg/kg/day and when compared with controls, statistically significant, dose-related, higher mean chloride level was noted in males (+2%) and lower mean inorganic phosphorus level was recorded in females (-17%) compared to controls. As mean values were within or close to the range of the Historical Control Data, in the absence of any correlates with microscopic observations on kidneys and/or in view of their slight magnitude, these differences were considered to be of minor toxicological importance.
The other differences from controls consisted of low mean inorganic phosphorus level (females at 10 or 30 mg/kg/day), low mean urea level (females from 10 mg/kg/day), high mean albumin level (females at 10 mg/kg/day), low mean cholesterol level (males at 100 mg/kg/day),high mean triglyceride level (males and females from 10 mg/kg/day), high mean alkaline phosphatase activity (females from 10 mg/kg/day), low mean aspartate aminotransferase activity (males from 10 mg/kg/day and females from 30 mg/kg/day) and/or low mean alanine aminotransferase activity (males from 10 mg/kg/day). In view of the slight magnitude and the direction of the changes, in the absence of effects in the other sex and/or relationships to microscopic findings, and/or as mean values were not dose-related and/or within the range of the Historical Control Data, and/or differences resulted from higher mean control values, these findings were not considered as toxicologically important.

Urinalysis findings:

not examined

Behaviour (functional findings):

effects observed, non-treatment-related

Description (incidence and severity):

There were no relevant differences between the test item-treated and control groups in motor activity (horizontal movements and rearing) in males and females.
At 10 mg/kg/day in males and females, differences from controls were noted in the mean number of horizontal movements (males: -24%) and rearing movements (males: -19% and females: +49%). Females given 100 mg/kg/day also showed variations in the mean number of rearing movements (+20% vs. controls). These values were considered to be of no toxicological importance as they were of opposite trend, not statistically significant, poorly dose-related and/or as values remained close to or within the standard deviation of control values.
There were no test item treatment-related neurologic abnormalities.
An absence of urination was recorded in 4/5 males at 30 or 100 mg/kg/day versus 2/5 control males and in 3/5 females at 10 or 100 mg/kg/day versus 1/5 control females. Absence of grooming was noted in 5/5 males at 30 or 100 mg/kg/day versus 3/5 control males and in 4/5 females at 100 mg/kg/day versus 2/5 in control females. Higher mean landing foot splay was recorded in males (102 mm vs. 68 mm in controls) and in females (108 mm vs. 94 mm in controls) at 100 mg/kg/day and higher mean rectal temperature (38.2°C vs. 37.4 in controls) was observed in males at 100 mg/kg/day. These findings were considered to be of no toxicological importance as they were within the range of physiological values and only observed in one sex (rectal temperature), poorly dose-related (urination) and/or did not correlate with each other, and/or with any other findings (urination, grooming, landing foot splay and rectal temperature).

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No relevant differences in organ weights between test item-treated and control groups were observed. Statistically significant differences were occasionally observed (minimal increases in pituitary weight in males at the low dose and in brain weight in females at the mid dose), but given the absence of dose relationship and the low magnitude of the changes, these differences were considered fortuitous.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Unscheduled deaths: Mid-dose female No. N23436 (30 mg/kg/day) was killed moribund on Day 42 because of difficulties to deliver. Relevant macroscopic observations were irregular tan discoloration of kidneys and reduced thymic size, correlating microscopically with marked necrosis and marked lymphoid atrophy, respectively. In the absence of similar changes in other test item-treated animals, including at the high-dose, these changes are considered to be related to dystocia and stress and not directly test item-related.

At the end of the treatment period : High dose female N23443 had white discoloration of the forestomach and thickening of the wall, which correlated microscopically with slight acanthosis.
All other macroscopic observations were spontaneous in nature. This includes a focal red discoloration of the stomach in high dose female N23442, with no histological correlate.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Dose-related hyperplasia of the squamous epithelium of the stomach was observed at all dose levels, except in males dosed at 10 mg/kg/day. It was accompanied by hyperkeratosis.
This finding is most probably related to local irritancy of the test item. It was not accompanied by noticeable inflammation and clinical signs and was therefore considered non adverse.

Histopathological findings: neoplastic:

no effects observed

Other effects:

no effects observed

Description (incidence and severity):

The thyroid hormone levels were considered to be unaffected by the test item in F0 males.
When compared with controls, there was a statistically significant, lower mean T4 concentration at 10 mg/kg/day and there were lower mean TSH concentrations from 10 mg/kg/day reaching statistically significance from 30 mg/kg/day. These variations were considered to be fortuitous as they did not correlate between each other, were not dose-related, remained within the range of the Historical Control Data and had no histopathological correlates on thyroid and pituitary glands.

Effect levels

1

Dose descriptor:

NOEL

Remarks:

(local toxicity)

Effect level:

< 10 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

2

Dose descriptor:

NOAEL

Remarks:

(systemic effects)

Effect level:

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

Based on:

test mat.

Sex:

male/female

Remarks on result:

not determinable due to absence of adverse toxic effects

Target system / organ toxicity

Critical effects observed:

no

Applicant's summary and conclusion

Conclusions:

Based on the experimental conditions of this study:the No Observed Adverse Effect Level (NOAEL) for parental systemic toxicity was considered to be 100 mg/kg/day in the absence of adverse findings at this high-dose level. And the No Observed Effect Level (NOEL) for parental local toxicity could not be determined as microscopic findings were observed in the stomach in females from 10 mg/kg/day and in males from 30 mg/kg/day.

Executive summary:

Three groups of ten male and ten female Sprague-Dawley rats received the test item, 2-Hydroxy-3-phenoxypropyl acrylate.The test item was administereddaily by the oral route (gavage) at dose levels of 10, 30 or 100 mg/kg/day, under a constant dosage volume of 5 mL/kg/day.

Males were treated for an overall period of at least 4 weeks: 2 weeks before mating, during the mating period (up to 1 week) and until the day before euthanasia. Females were treated for an overall period of 7 to 8 weeks: 2 weeks before mating, throughout mating (up to 4 days) and gestation (3 weeks) until Day 13post-partum(p.p.) inclusive. A control group of ten males and ten females received the vehicle only (0.5% methylcellulose aqueous solution) under the same experimental conditions.

There were no test item-related unscheduled deaths. Ptyalism occurred in both sexes and in all test item-treated groups during the premating period, with the exception of males at 30 mg/kg/day, and persisted in some females at 100 mg/kg/day during the gestation period. This sign, commonly observed when a test item is administered by gavage, was not considered as an adverse effect.There were no relevant effects on Functional Observation Battery tests or motor activity data at any dose level.

There were no statistically significant differences on mean body weight or mean body weight change at any dose level in males or in females during the premating, gestation and lactation periods. At 100 mg/kg/day and when compared with controls, a few variations of body weight gain were noted in females during the lactation period. These differences were considered to be related to the test item but of minor toxicological importance in view of their slight magnitude and in the absence of effects on body weight.

There were no relevant effects on food consumption at any dose level.

There were no statistically significant test item-related effects on hematology parameters at any dose level. Minor changes observed were considered to be of no toxicological importance as they did not correlate with microscopic findings, were of slight magnitude, poorly dose-related, and/or within or close to the range of the Historical Control Data.

At 100 mg/kg/day andwhen compared with controls,blood biochemistry changes included increased chloride level in males (+2%, p<0.05) and decreased inorganic phosphorus level in females (-17%, p<0.05). In view of their magnitude, as mean values remained within the range of the Historical Control Data and in absence of histopathological findings on kidneys, these changes were considered to be of minor toxicological importance.

There were notest item-related effects onT4 or TSH levels in F0 males or pups at any dose level.

 

There were no relevant differences in organ weights between test item-treated and control groups. Dose-related hyperplasia of the squamous epithelium of the stomach, accompanied by hyperkeratosis, possibly related to a local irritant effect was observed in the stomach in 1/5 females at 10 mg/kg/day, 3/5 males and 3/5 females at 30 mg/kg/day and in 4/5 males and 5/5 females at 100 mg/kg/day. This change was not accompanied by noticeable inflammation and was considered non adverse.

Based on the experimental conditions of this study:the No Observed Adverse Effect Level (NOAEL) for parental systemic toxicity was considered to be 100 mg/kg/day in the absence of adverse findings at this high-dose level. And the No Observed Effect Level (NOEL) for parental local toxicity could not be determined as microscopic findings were observed in the stomach in females from 10 mg/kg/day and in males from 30 mg/kg/day.