Zinc methacrylate

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

9 August 2012 - 22 February 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

other: Audited draft report

Title:

Unnamed

Year:

2013

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

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Hydroxy(2-methylprop-2-enoato-O)zinc

EC Number:

264-202-2

EC Name:

Hydroxy(2-methylprop-2-enoato-O)zinc

Cas Number:

63451-47-8

Molecular formula:

C4H6O3Zn

IUPAC Name:

hydroxy(2-methylprop-2-enoato-O)zinc

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Hydroxy(2-methylprop-2-enoato-O)zinc
- Physical state: White powder
- Analytical purity: >85.5%
- Lot/batch No.: Y1109025
- Expiration date of the lot/batch: 15 December 2012
- Storage condition of test material: At ambient temperature; protected from light and humidity.

Test animals

Species:

rat

Strain:

other: Crl:CD(SD) rat

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Limited
- Age of F0 animals at study initiation: Approximately 10 weeks
- Weight of F0 animals at study initiation: Males: 327-388 g; Females: 229-280 g
- Housing: No. of animals per cage - Pre-pairing: 5 males and 5 females; during pairing: 1 male and 1 female; Males after mating: 5 animals; Gestation: 1 female; Lactation: 1 female + litter. Solid (polycarbonate) bottom cages were used during the acclimatisation, pre-pairing, gestation, littering and lactation periods. Grid bottomed cages were used during pairing. These were suspended above absorbent paper which was changed daily during pairing.
- Diet (e.g. ad libitum): SDS VRF1 Certified pelleted diet, ad libitum
- Water (e.g. ad libitum): Potable water from the public supply via polycarbonate bottles with sipper tubes, ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 19-23 °C
- Humidity: 40-70 %
- Air changes: Filtered fresh air which was passed to atmosphere and not recirculated.
- Photoperiod: 12 h dark / 12 h fluorescent light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 0.5 % sodium carboxymethylcellulose

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
- The test substance, Hydroxy(2-methylprop-2-enoato-O)zinc was prepared for administration as a series of graded concentrations in the vehicle. Starting with the lowest concentration, the required amount of Hydroxy(2-methylprop-2-enoato-O)zinc was weighed, transferred to a suitably sized mortar and ground to a fine powder using a pestle. Small amounts of the vehicle were added and mixed with the test substance to form a smooth paste, ensuring any agglomerates were broken down at this stage. The suspension was poured into a measuring cylinder which had been wetted with the vehicle. The mortar was rinsed thoroughly with the vehicle and the rinsed residue was added to the measuring cylinder. The required volume was achieved by addition of the remaining vehicle, and the suspension was transferred to a beaker and mixed using a high shear homogeniser until homogenous. During magnetic stirring, the suspension was transferred to the final containers. Remaining concentrations were prepared in ascending group order using the same method. All formulations were prepared freshly each week and stored refrigerated (2-8 °C) before use.

VEHICLE
- Concentration in vehicle: 10, 30 and 100 mg/mL
- Amount of vehicle (if gavage): 10 mL/kg bw/day

STABILITY:
- The homogeneity and stability of Hydroxy(2-methylprop-2-enoato-O)zinc in 0.5% sodium carboxymethylcellulose formulations was assessed with respect to the level of concentration at nominal concentrations of 1 and 200 mg/mL. Homogeneity and stability were confirmed during distribution between the bottles, during magnetic stirring for 2 h, and on re-suspension following storage at ambient temperature for 1 day and refrigeration for up to 15 days. At each time-point, the mean analysed concentration for the three samples remained within 2 % of the initial time zero value and the coefficient of variation was less than 3 %.
- The discrete stability in volumetric flasks was confirmed following refrigerated storage for up to 15 days, the mean analysed concentration remained within 10 % of the initial time zero value.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

- Samples of each formulation prepared for administration in Weeks 1 and 4 of treatment were analysed for achieved concentration of the test substance.
- Results: Mean concentrations of Hydroxy(2-methylprop-2-enoato-O)zinc in test formulations analysed were within applied limits +10%/-15%, confirming the accuracy of formulation.

Duration of treatment / exposure:

- F0 males were treated for two weeks before pairing up to necropsy after a minimum of five weeks.
- F0 females were treated daily for two weeks before pairing, throughout pairing, gestation and lactation until the day prior to termination on Day 7 of lactation.

Frequency of treatment:

Once daily

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 100, 300 and 1000 mg/kg bw/day
Basis:
actual ingested

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dose levels chosen for investigation in this study (0, 100, 300 or 1000 mg/kg bw/day) were selected based on the results of a 14-day toxicity study by oral (gavage) administration to CD rats (Huntingdon Life Sciences Study No. AJY0027).
- Rationale for animal assignment: Randomly allocated on arrival. Using the sequence of cages in the battery, one animal at a time was placed in each cage with the procedure being repeated until each cage held the appropriate number of animals.

Positive control:

Not applicable

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Animals were inspected visually at least twice daily for evidence of ill-health or reaction to treatment. During the acclimatisation period, observations of the animals and their cages were recorded at least once per day.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily during the first week of treatment, weekly from Week 2 for all F0 animals and on Days 0, 6, 13 and 20 of gestation and Days 1 and 6 of lactation for F0 females. Viability check was performed near the start and end of each working day. Before treatment commenced, weekly during each week of treatment for all F0 animals and on Days 0, 6, 13 and 20 after mating and Days 1 and 6 of lactation for F0 females, detailed physical examination and arena observations were performed.

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule: Examinations were performed on the five lowest numbered surviving males in each group prior to dose administration during Week 5 of treatment and on the five lowest numbered lactating females in each group on Days 4-6 of lactation (except in the 1000 mg/kg bw/day group, where only two females survived to this stage).
- Parameters: Sensory reactivity and grip strength and motor activity

BODY WEIGHT: Yes
- Time schedule for examinations:
F0 animals: The day that treatment commenced (Week 0), weekly thereafter and on the day of necropsy.
F0 females after mating: Days 0, 6, 13 and 20 after mating, and Days 1, 4 and 7 of lactation.

FOOD CONSUMPTION: Yes
- Time schedule for examinations:
F0 animals: Weekly until paired for mating. Food consumption was not recorded during pairing (Week 3) and then recommenced in Week 4 for the F0 males.
F0 females after mating: Days 0-5, 6-12, 13-19 and Days 1-3 and 4-6 of lactation.

WATER CONSUMPTION: No

HAEMATOLOGY AND CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Week 2 of treatment. The five lowest numbered surviving F0 males and females per group.
- Animals fasted: Yes, overnight fasting
- Animals were held under light general anaesthesia induced by isoflurane. Blood samples (nominally 0.5 mL) were withdrawn from the sublingual vein.
- Haematology parameters: Haematocrit, Haemoglobin concentration, Erythrocyte count (RBC), Absolute reticulocyte count, Mean cell haemoglobin, Mean cell haemoglobin concentration, Mean cell volume, Total leucocyte count, Differential leucocyte count: Neutrophils, Lymphocytes, Eosinophils, Basophils, Monocytes, Large unstained cells, Platelet count, Morphology: Anisocytosis, Macrocytosis, Microcytosis, Hypochromasia, Hyperchromasia, Prothrombin time and Activated partial thromboplastin time.
- Blood Chemistry parameters: Alkaline phosphatase (ALP), Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Gamma-glutamyl transpeptidase (gGT), Total bilirubin, Urea, Creatinine, Glucose, Total cholesterol, Triglycerides, Sodium (Na), Potassium (K), Chloride (Cl), Calcium (Ca), Inorganic phosphorus, Bile acids, Total protein, Albumin - by chemical assay and Albumin/globulin ratio (A/G Ratio).

PARTURITION:
- From Day 20 after mating, females were inspected three times daily for evidence of parturition. The progress and completion of parturition was monitored, numbers of live and dead offspring were recorded and any difficulties observed were recorded.

Sacrifice and pathology:

SACRIFICE
- F0 males: After Week 5 investigations completed.
- F0 females: Scheduled kill - Day 7 of lactation; Failing to produce viable litter - Day 25 after mating; Litter death before Day 7 of lactation - on or after day last offspring dies.
- Method of sacrifice: Carbon dioxide asphyxiation with subsequent exsanguination.

GROSS NECROPSY
- F0 Females:
Each uterine horn - Number of implantation sites
Females failing to produce a viable litter - The number of uterine implantation sites were checked after staining with ammonium sulphide (modification of the Salewski staining technique (Salewski 1964)).
- All external features and orifices were examined visually. Any abnormality in the appearance or size of any organ and tissue (external and cut surface) was recorded and the required tissue samples preserved in appropriate fixative. See table 7.8.1/1 for further details.

HISTOPATHOLOGY / ORGAN WEIGHTS
- The organs weighed, tissue samples fixed and sections examined microscopically are detailed in table 7.8.1/1.

Other examinations:

DETAILS ON MATING PROCEDURE
- M/F ratio per cage: 1: 1
- Length of cohabitation: Up to 2 weeks
- Proof of pregnancy: Presence of sperm within the vaginal smear and/or ejected copulation plugs referred to as Day 0 of pregnancy.

Statistics:

See section "Any other information on materials and methods incl. tables”.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

refer to "details on results" section

Mortality:

mortality observed, treatment-related

Description (incidence):

refer to "details on results" section

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

refer to "details on results" section

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

refer to "details on results" section

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):

refer to "details on results" section

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

refer to "details on results" section

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

refer to "details on results" section

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

refer to "details on results" section

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

refer to "details on results" section

Histopathological findings: neoplastic:

not examined

Details on results:

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
- Treatment with Hydroxy(2-methylprop-2-enoato-O)zinc at 1000 mg/kg bw/day was not tolerated by pregnant/lactating females, with 7/10 females prematurely killed between mid-gestation and Day 1 of lactation. One female was killed for welfare reasons on Day 12 of gestation due to deteriorating clinical condition suggested possible disturbance to the respiratory tract. The remaining six females that were prematurely killed showed evidence of abnormal parturition, manifest as either failure of onset or completion. These females had all shown low weight gain during the last week of gestation, and were killed for welfare reasons between Day 23 of gestation and formal assignment to Day 1 of lactation due to deteriorating clinical condition; three of these females had shown no evidence of the onset of parturition and three had given birth to a small number of pups, however all of the females were found to have several pups retained in utero, the majority of which were dead, and therefore the aetiology of the poor clinical condition of the six females was considered to be attributable to intrauterine fetal deaths. Among parental animals that survived to scheduled termination, there were no signs observed during the detailed arena observations/physical examinations or in relation to dose administration that were attributable to treatment.

BODY WEIGHT (PARENTAL ANIMALS)
- At 1000 mg/kg bw/day, overall mean bodyweight gain of males during the course of the study was 0.80X Control, attributable to reduced weight gain during the first two weeks of treatment. In females at this dose level, mean weight gain was unaffected in Week 1, but lower than Control during Week 2 (0.40X Control) due to two females which recorded weight loss during this period. Thereafter, mean weight gain of these females was similar to Control until the final week of gestation, when the marked decline in clinical condition became apparent. Bodyweight performance of animals receiving 100 or 300 mg/kg bw/day was unaffected by treatment.

FOOD CONSUMPTION (PARENTAL ANIMALS)
- Food consumption of males and females receiving 1000 mg/kg bw/day was slightly lower than Control during Week 1 of treatment. Thereafter, mean food intake of all groups of treated animals was similar to Control.

NEUROBEHAVIOURAL EXAMINATION (PARENTAL ANIMALS)
Sensory reactivity, grip strength and motor activity were unaffected by treatment with Hydroxy(2-methylprop-2-enoato-O)zinc.

HAEMATOLOGY (PARENTAL ANIMALS)
- A dose-dependent decrease in haematocrit and haemoglobin concentration was evident in all groups of treated males after 2 weeks of treatment. At 1000 mg/kg bw/day, decreases in erythrocytes, mean cell haemoglobin and mean cell volume and an increase in red cell distribution width were apparent in males and females, with females also showing a decrease in haematocrit, haemoglobin concentration and mean cell haemoglobin concentration. Assessment of leucocytic parameters revealed an increase in all leucocyte parameters at 1000 mg/kg bw/day, particularly neutrophil concentrations in males and females and eosinophil concentrations in males, with an associated increase in total white blood cell counts; females also showed an increase in platelet counts.

BLOOD CHEMISTRY (PARENTAL ANIMALS)
- Among animals receiving 1000 mg/kg bw/day, biochemical analysis of blood plasma revealed an increase in alkaline phosphatase and alanine amino-transferase activities and bilirubin concentrations and a reduction in total protein and albumin concentrations in males and females after 2 weeks of treatment. Males also showed a decrease in bile acids and increased triglyceride concentrations, and females a decrease in aspartate amino-transferase activity and cholesterol concentrations. Chloride concentrations were high for males receiving 300 or 1000 mg/kg bw/day and for females receiving 1000 mg/kg bw/day.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
- Mating performance and fertility of the F0 generation animals, as assessed by pre-coital interval, percentage mating and conception rate were unaffected by treatment with Hydroxy(2-methylprop-2-enoato-O)zinc. All animals mated at the first oestrus opportunity after cohabitation. Gestation length, parturition and gestation index of females receiving 1000 mg/kg bw/day was adversely affected by treatment with Hydroxy(2-methylprop-2-enoato-O)zinc. Of the eight pregnant females in the dose group which survived to the end of gestation, only two dams completed parturition and one of these two females had a gestation length of 23.5 days, slightly longer than the expected range of 22-23 days. Abnormal parturition was apparent in the remaining six pregnant females requiring premature termination of these animals; either the onset of parturition did not occur, or a small number of pups were born with the remainder retained in utero. At 300 mg/kg bw/day, there was a suggestion of a slight shift towards a longer gestation length with 5/10 females showing a gestation length of 23 days compared to 2/10 Controls.
- Among females receiving 1000 mg/kg bw/day that survived to scheduled termination on Day 7 of lactation, there was a suggestion of a slight reduction in implantation counts, with a concomitant slight reduction total litter size on Day 1 of lactation.

ORGAN WEIGHTS (PARENTAL ANIMALS)
- At scheduled termination, changes in organ weights were limited to increased spleen weights among males receiving 1000 mg/kg bw/day and increased kidney weights in females at 1000 mg/kg bw/day; there were no associated macroscopic/microscopic abnormalities in these organs to explain the differences in weight.

GROSS PATHOLOGY (PARENTAL ANIMALS)
- Macroscopic examination revealed pale areas in the prostate of 2 out of 10 males receiving 300 mg/kg bw/day and 4 out of 10 males receiving 1000 mg/kg bw/day.

HISTOPATHOLOGY (PARENTAL ANIMALS)
- Treatment-related histopathological changes occurred in the stomach, duodenum, pancreas, eyes, and prostate.
- In the stomach, abnormalities comprised: a dose dependent incidence/severity of inflammatory cell infiltrate composed of a variable number of eosinophils and neutrophils and globule leukocytes infiltration in the glandular stomach in males and females at 300 and 1000 mg/kg bw/day; minor inflammatory changes at 100 mg/kg bw/day; mucosal erosion/ulceration in females at 1000 mg/kg bw/day; focal intestinal metaplasia in the glandular stomach in a single male at 1000 mg/kg bw/day.
- At 1000 mg/kg bw/day, slight villous hypertrophy, characterised by a diffuse increase in villous height was seen in in the duodenum, moderate acinar degeneration/atrophy was observed in the pancreas and slight to moderate retinal atrophy in the eyes.
- In the prostate, suppurative inflammation/abscess(es) was seen with increased degree/severity at 300 and 1000 mg/kg bw/day. Minor inflammatory changes in the prostate were also seen in a single male given 100 mg/kg bw/day.
- Histopathological changes detected among the females killed prematurely at 1000 mg/kg bw/day which were considered secondary effects of treatment comprised: minimal to slight leukocytic infiltration of the endometrium of the uterus (in the presence of dead fetuses); cortical hypertrophy of the adrenal glands; involution/atrophy of the thymus.

Effect levels

Key result

Dose descriptor:

NOAEL

Remarks:

systemic toxicity

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

None

Applicant's summary and conclusion

Conclusions:

Under the study conditions, the NOAEL for systemic toxicity was considered to be 100 mg/kg bw/day in male and female rats.

Executive summary:

In a GLP-compliant Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test conducted according to OECD Guideline 422, the test item Hydroxy(2-methylprop-2-enoato-O)zinc was administered to three groups of Crl:CD(SD) rats at 0, 100, 300 and 1000 mg/kg bw/day by oral (gavage). The F0 males were treated for two weeks before pairing up to necropsy after a minimum of five weeks. The F0 females were treated daily for two weeks before pairing, throughout pairing, during gestation and lactation until the day prior to termination on Day 7 of lactation. During the study, data was recorded on mortality, clinical signs, behavioural assessments, body weight change, food and water consumption, haematology, blood chemistry, mating performance, fertility and gestation length. All animals were subjected to a gross necropsy examination, selected organs were weighed and histopathological evaluation of selected tissues was performed. Treatment with Hydroxy(2-methylprop-2-enoato-O)zinc at 1000 mg/kg bw/day was not tolerated by pregnant/lactating females, with 7/10 females prematurely killed between mid-gestation and Day 1 of lactation; in this 6/7 females showed evidence of abnormal parturition. All of the females were found to have several pups retained in utero, the majority of which were dead, and therefore the aetiology of the poor clinical condition of the six females was considered to be attributable to intrauterine fetal deaths. At 1000 mg/kg bw/day, overall mean bodyweight gain of males during the course of the study was 0.80X Control, attributable to reduced weight gain during the first two weeks of treatment. In females at this dose level, mean weight gain was unaffected in Week 1, but lower than Control during Week 2 (0.40X Control) due to two females which recorded weight loss during this period. Thereafter, mean weight gain of these females was similar to Control until the final week of gestation, when the marked decline in clinical condition became apparent. Bodyweight performance of animals receiving 100 or 300 mg/kg bw/day was unaffected by treatment. Food consumption of males and females receiving 1000 mg/kg bw/day was slightly lower than Control during Week 1 of treatment. Thereafter, mean food intake of all groups of treated animals was similar to Control. Sensory reactivity, grip strength and motor activity were unaffected by treatment with test item. A dose-dependent decrease in haematocrit and haemoglobin concentration was evident in all groups of treated males after 2 weeks of treatment. At 1000 mg/kg bw/day, decreases in erythrocytes, mean cell haemoglobin and mean cell volume and an increase in red cell distribution width were apparent in males and females, with females also showing a decrease in haematocrit, haemoglobin concentration and mean cell haemoglobin concentration. At 1000 mg/kg bw/day, an increase in all leucocyte parameters, particularly neutrophil concentrations in males and females and eosinophil concentrations in males, with an increase in total white blood cell counts; females also showed an increase in platelet counts. At 1000 mg/kg bw/day, an increase in alkaline phosphatase and alanine amino-transferase activities and bilirubin concentrations and a reduction in total protein and albumin concentrations in males and females were observed after 2 weeks of treatment. Males also showed a decrease in bile acids and increased triglyceride concentrations, and females a decrease in aspartate amino-transferase activity and cholesterol concentrations. Chloride concentrations were high for males receiving 300 or 1000 mg/kg bw/day and for females receiving 1000 mg/kg bw/day. Mating performance and fertility of the F0 generation animals were unaffected by treatment. Gestation length, parturition and gestation index of females receiving 1000 mg/kg bw/day was adversely affected by treatment with test item. Of the eight pregnant females in the dose group which survived to the end of gestation, only two dams completed parturition and one of these two females had a gestation length of 23.5 days, slightly longer than the expected range of 22-23 days. Abnormal parturition was apparent in the remaining six pregnant females requiring premature termination of these animals; either the onset of parturition did not occur, or a small number of pups were born with the remainder retained in utero. At 300 mg/kg bw/day, there was a suggestion of a slight shift towards a longer gestation length with 5/10 females showing a gestation length of 23 days compared to 2/10 Controls. Among females receiving 1000 mg/kg bw/day that survived to scheduled termination on Day 7 of lactation, there was a suggestion of a slight reduction in implantation counts, with a concomitant slight reduction total litter size on Day 1 of lactation. At scheduled termination, there were increased spleen weights in males and increased kidney weights in females at 1000 mg/kg bw/day without any association of macroscopic/microscopic abnormalities. Macroscopic examination revealed pale areas in the prostate of 2/10 males receiving 300 mg/kg bw/day and 4/10 males receiving 1000 mg/kg bw/day. Treatment-related histopathological changes occurred in the stomach, duodenum, pancreas, eyes, and prostate. In the stomach, a dose dependent incidence/severity of inflammatory cell infiltrate composed of a variable number of eosinophils and neutrophils and globule leukocytes infiltration in the glandular stomach in males and females at 300 and 1000 mg/kg bw/day; minor inflammatory changes at 100 mg/kg bw/day; mucosal erosion/ulceration in females at 1000 mg/kg bw/day; focal intestinal metaplasia in the glandular stomach in a single male at 1000 mg/kg bw/day. At 1000 mg/kg bw/day, slight villous hypertrophy, characterised by a diffuse increase in villous height was seen in in the duodenum, moderate acinar degeneration/atrophy was observed in the pancreas and slight to moderate retinal atrophy in the eyes. In the prostate, suppurative inflammation/abscess(es) was seen with increased degree/severity at 300 and 1000 mg/kg bw/day. Minor inflammatory changes in the prostate were also seen in a single male at 100 mg/kg bw/day. Histopathological changes detected among the females killed prematurely at 1000 mg/kg bw/day which were considered secondary effects of treatment comprised: minimal to slight leukocytic infiltration of the endometrium of the uterus (in the presence of dead fetuses); cortical hypertrophy of the adrenal glands; involution/atrophy of the thymus. Under the test condition, the NOAEL for systemic toxicity was considered to be 100 mg/kg bw/day in male and female rats (Stanndard, 2013).