Polymer with 2-Butyne-1,4-Diol and (Chloromethyl-)Oxirane, Brominated, Dehydrochlorinated, Methoxylated

Endpoint summary

Description of key information

A 4-week inhalation toxicity study has been conducted with Polyol IXOL M125 in which rats were exposed for 6 hours/day, 5 days/week. The NOAEL for systemic effects of Polyol IXOL M125 was considered to be 290 mg/m3 for females and 950 mg/m3 for males. Since evidence of local toxicity in the upper respiratory tract was still found at this concentration, a NOAEC for local effects could not be established. Exposure to the structural analogue Polyol IXOL® B350 at concentrations up to 300 mg/m3 (the highest concentration tested) for 90 days, did not result in any treatment-related changes in the parameters tested. Therefore, the high concentration level of 300 mg/m3 was also considered to be the No-Observed-Adverse-Effect-Level (NOAEL) for systemic and local toxicity for Polyol IXOL M125.

Based on read-across from the structural analogue Polyol IXOL B350, the most critical effect for IXOL M125 after repeated oral exposure are expected to be effects on the kidney. Oral exposure to Polyol IXOL B350 (OECD 443, GLP) at dosages of 0, 75, 150 and 450 mg/kg bw/day resulted in treatment-related adverse findings consisting of intratubular hemorrhage in the kidneys of F0 males administered 450 mg/kg/day and thyroid adenomas in F0 males adminstered ≥ 75 mg/kg/day, one female adminstered 450 mg/kg/day, and one F1 male administered 75 mg/kg/day. It should be noted that the relevance of such thyroid effects in rat studies - in quantitative terms - to humans is limited. Therefore the kidney effect is considered the most critical effect of Polyol IXOL B350 after repeated oral exposure. Based on the available study, the overall NOAEL for systemic effects is 150 mg/kg bw/day.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

150 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Quality of whole database:

GLP complaint OECD guideline study, klimisch 1

Organ:

kidney

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-compliant guideline study, available as unpublished report, no restrictions, fully adequate for assessment.

Qualifier:

according to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories
- Age at study initiation: 8 weeks
- Weight at study initiation: main study: 270 g (males) and 179 g (females),
- Housing: in macrolon cages with a bedding of wood shavings and strips of paper as environmental enrichment; 5 animals of the same sex per cage
- Diet: Rat & Mouse No. 3 Breeding Diet, RM3, ad libitum, except during exposure and fasting period before blood withdrawal
- Water: domestic tap water suitable for human consumption, ad libitum, except during exposure and fasting period before blood withdrawal
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3
- Humidity (%): 30-70
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

clean air

Remarks on MMAD:

MMAD / GSD: The average MMAD for the low, mid and high concentration groups were 2.3 µm (gsd of 2.5), 2.0 µm (gsd of 2.5) and 2.2 µm (gsd of 2.5) respectively.

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: nose-only exposure units (a modification of the design of the chamber manufactured by ADG Developments Ltd., Codicote, Hitchin, Herts, SG4 8UB, United Kingdom) consisting of a cylindrical polypropylene (group 1) or aluminium (groups 2-5) column, surrounded by a transparent cylinder.
- Method of holding animals in test chamber: plastic animal holders (Battelle), positioned radially through the outer cylinder around the central column
- Source of air: humidified compressed air
- System of generating particulates/aerosols: heated air-driven atomizer (Schlick type 970/S, Coburg, Germany) placed at the top inlet of the exposure chamber
- Method of particle size determination: Particle size distribution measurements were carried out using a 10-stage cascade impactor (2110k, Sierra Instruments, Canne Valley, California, USA) once weekly and at least once during preliminary generation of the test atmosphere for each exposure
condition. The Mass Median Aerodynamic Diameter (MMAD) and the geometric standard deviation (gsd) were be calculated
- Temperature and humidity in exposure chamber: 21.7 (± 0.4)°C, 22.9 (± 0.5)°C, 23.0 (± 0.4)°C and 23.1 (± 0.3) °C for the control, low, mid and high concentration groups, resp.; 40.1 (± 3.1)%, 48.5 (± 2.7)%, 47.9 (± 2.7)% and 48.1 (± 2.7) % for the control, low, mid and high concentration groups, resp.

TEST ATMOSPHERE
- Brief description of analytical method used: The actual concentration (by weight) of the non-volatile fraction of Polyol IXOL B 350 in the test atmospheres was determined at least three times per day during each exposure by means of gravimetric analysis.
- Samples taken from breathing zone: yes

VEHICLE (if applicable)
- Justification for use and choice of vehicle: To generate the test atmospheres, the test material was diluted with water (70% Polyol IXOL B 350 and 30% water, based on weight; solutions were prepared weekly)
- Concentration of test material in vehicle: 70%

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The actual concentration (by weight) of the non-volatile fraction of Polyol IXOL B 350 in the test atmospheres was determined at least three times per day during each exposure by means of gravimetric analysis. Representative test atmosphere samples were obtained by passing the test atmosphere at 4.6 Ln/min through fiber glass filters (Sartorius 13400-47) for groups 2, 3, 4 or respectively. Filters were weighed before sampling, loaded with a sample of test atmosphere and weighed again. During preliminary measurements, it was established that drying of the loaded filters was not necessary, because the weight was constant.
To investigate whether filter weights should be corrected for dry matter content or possible hygroscopy of the test material, known amounts of undiluted Polyol IXOL B 350 were applied to glass fiber filters and the filters were dried with ambient air until a stable filter weight was reached. The percentage of captured weight on the filters was 102.8% for Polyol IXOL B 350, indicating slight hygroscopy of the test materials. This percentage was used to correct the weight of the filters after test atmosphere sampling for gravimetric analysis.

Duration of treatment / exposure:

90 days

Frequency of treatment:

6 hours/day, 5 days/week

Dose / conc.:

30 mg/m³ air (nominal)

Dose / conc.:

100 mg/m³ air (nominal)

Dose / conc.:

300 mg/m³ air (nominal)

Dose / conc.:

30.14 mg/m³ air (analytical)

Remarks:

SD ± 3.21

Dose / conc.:

100.1 mg/m³ air (analytical)

Remarks:

SD ± 4.54

Dose / conc.:

300.7 mg/m³ air (analytical)

Remarks:

SD ± 25.46

No. of animals per sex per dose:

10/sex/dose

Control animals:

yes

Details on study design:

- Dose selection rationale: based on the results of two previously performed sub-acute (28-day) inhalation studies
- Rationale for animal assignment (if not random): computer randomization proportionally to body weight (males and females separately)

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily in the morning hours; a group-wise observation was made halfway through each exposure day. During exposure, special
attention was paid to any breathing abnormalities and restlessness; observation of other abnormalities was limited due to the animals’ stay in restraining tubes.

BODY WEIGHT: Yes
- Time schedule for examinations: The body weight of each animal was recorded three (males) or four days (females) before the start of exposure and prior to exposure on the first day (day 0). Subsequently, animals of the range finding study were weighed twice weekly for the first four weeks (Mondays and Fridays). Thereafter, the frequency was reduced to once weekly (Fridays), because there were no statistically significant effects on body weight in the first four weeks. At the end of the in-life phase, the animals were weighed on the day before overnight fasting prior to their scheduled sacrifice, and on the day of sacrifice in order to calculate the correct organ to body weight ratios.

FOOD CONSUMPTION:
- Food consumption was measured per cage by weighing the feeders. The consumption was measured over 7-day periods, except at the start (a 4-day period for males; a 3-day period for females) and at the end of the exposure period (a 3-day period for males; a 4-day period for females). The results were expressed in g per animal per day.

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at necropsy from the abdominal aorta of overnight fasted rats
- Anaesthetic used for blood collection: Yes (phenobarbital)
- Animals fasted: Yes, overnight
- How many animals: all animals
- Parameters examined: haemoglobin, packed cell volume, red blood cell count, reticulocytes, total white blood cell count, differential white blood cell count, prothrombin time, trombocyte count, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at necropsy from the abdominal aorta of overnight fasted rats
- Anaesthetic used for blood collection: Yes (phenobarbital)
- Animals fasted: yes, overnight
- How many animals: all animals
- Parameters examined: alkaline phosphatase activity (ALP), aspartate aminotransferase activity (ASAT), alanine aminotransferase activity (ALAT), gamma glutamyl transferase activity (GGT), total protein, albumin, ratio albumin to globulin, urea, creatinine, fasting glucose, bilirubin total, cholesterol, triglycerides, phospholipids, calcium, sodium, potassium, chloride, inorganic phosphate

Sacrifice and pathology:

GROSS PATHOLOGY:
Yes, the weights of the following organs were determined: adrenals, brain, epididymides, heart, kidneys, liver, lungs with trachea and larynx, spleen, testes, thymus, thyroid, ovaries, uterus
HISTOPATHOLOGY:
For histopathological examination, samples of the following tissues and organs of all animals of groups 1-4 were preserved in a neutral aqueous phosphate-buffered 4 per cent solution of formaldehyde (10% solution of formalin). The lungs (after weighing) were infused with the fixative under ca. 15 cm water pressure to insure fixation.
- adrenals,
- aorta,
- axillary lymph nodes,
- brain (brain stem, cerebrum, cerebellum),
- caecum,
- colon,
- epididymides,
- eyes (with optic nerve),
- exorbital lachrymal glands,
- femur with joint,
- heart,
- kidneys,
- liver,
- lungs/trachea/larynx,
- mammary glands (females),
- cervical lymph nodes,
- nasopharyngeal tissue (with nasal associated lymphoid tissue and teeth),
- nerve peripheral,
- oesophagus,
- olfactory bulb,
- ovaries,
- pancreas,
- parathyroids,
- pharynx,
- parotid salivary glands,
- pituitary,
- prostate,
- rectum,
- seminal vesicles,
- skeletal muscle,
- skin (flank),
- small intestines,
- spinal cord (cervical, mid-thoracic, and lumbar),
- spleen,
- sternum with bone marrow,
- stomach,
- sublingual salivary glands and submaxillary salivary glands,
- testes,
- thymus,
- thyroid,
- tongue,
- tracheobroncial (mediastinal) lymph nodes,
- ureter,
- urethra,
- urinary bladder,
- uterus (with cervix).

Slide preparation
Tissues to be examined were embedded in paraffin wax, sectioned at 5 μm and stained with haematoxylin and eosin.
 
Histopathological examination
All preserved tissues of all animals of the control and high concentration groups were examined histopathologically (by light microscopy). In addition, all relevant gross lesions observed in rats of the intermediate concentration groups were examined microscopically. The nasopharyngeal tissues were examined at 6 levels with 1 level to include the nasopharyngeal duct and the Nasal Associated Lymphoid Tissue (NALT), the larynx at 3 levels (1 level to include the base of the epiglottis), the trachea at 3 levels (including the bifurcation, and 1 longitudinal section through the carina), and each lung lobe at 1 level.

Other examinations:

Functional Observational Battery (FAB) and measurement of motor activity were included in the study.
Urinalysis was performed. The following determination were carried out in individual samples:
- volume,
- density,
- appearance,
- dipstick measurements (pH, glucose, occult blood, ketones, protein, bilirubin, urobilinogen)
- microscopic examination of the sediment (red blood cells, white blood cells, epithelial cells, amorphous material, crystals, casts, bacteria, sperm cells, worm eggs).

Statistics:

Body weight data collected after initiation of treatment: ‘Ancova & Dunnett’s Test’ with ‘Automatic’ as data transformation method.
Pretreatment body weight, Haematology, clinical chemistry, quantitative urinalysis and organ weight data: ‘Generalised Anova/Ancova Test’ with ‘Automatic’ as data transformation method.
Food consumption data: Dunnett’s multiple comparison test.
Incidences of histopathological changes: Fisher’s exact probability test.
Tests are performed as two-sided tests with results taken as significant where the probability of the results is <0.05 or <0.01.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

no effects observed

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

no effects observed

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

The exposure to the test material up to a concentration of 300.70 mg/m3 was well tolerated as evidenced by the absence of any relevant toxicological effect. Clinical, neurobehavioural and ophthalmoscopic observations; growth and food consumption results; haematology, clinical chemistry and urinalysis parameters; organ weights; and necropsy and histopathology findings did not reveal any exposure-related changes.

Dose descriptor:

NOAEC

Remarks:

local and systemic effects

Effect level:

300 mg/m³ air (analytical)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No treatment-related effects observed at the highest concentration tested.

Critical effects observed:

no

Conclusions:

Exposure to Polyol IXOL® B350 at concentrations up to 300 mg/m3 (the highest concentration tested) for 90 days, did not result in any treatment-related changes in the parameters tested. Therefore, the high concentration level of 300 mg/m3 was considered to be the No-Observed-Adverse-Effect-Level (NOAEL) for sub-chronic inhalation exposure to Polyol IXOL®B350 in male and female rats.

Executive summary:

The inhalation toxicity of Polyol IXOL® B350 was studied in a GLP compliant sub-chronic inhalation toxicity study in Wistar rats according to OECD Guideline 413. Four groups of 10 male and 10 female rats were exposed nose-only to target concentrations of 0 (control), 30, 100 or 300 mg/m3 Polyol IXOL® B350 for 6 hours/day, 5 days/week over a 14-week period, with a total of 65 exposure days. The animals were sacrificed on the day after the last exposure. To investigate the toxicity, data on clinical and neurobehavioural observations, ophthalmoscopy, body weight, food consumption, urinalysis haematology and clinical chemistry were collected. At necropsy, the animals were examined for gross macroscopic abnormalities, organs were weighed and a selection of organs and tissues (including the complete respiratory tract with nasal passages) was examined microscopically.

The mean actual concentrations (± standard deviation) as measured by gravimetric analysis were very close to the target concentrations, i.e. 30.14 (± 3.21), 100.06 (± 4.54) and 300.70 (± 25.46) mg/m3 Polyol IXOL® B350 for the low, mid and high concentration groups, respectively.

All animals survived until scheduled sacrifice. No treatment-related clinical or ophthalmoscopic abnormalities were observed in response to the exposure to Polyol IXOL® B350. Neurobehavioural observations (arena and Functional Observational Battery testing) and motor activity assessment did not indicate any neurotoxic potential of the test material. Treatment-related differences in growth or food consumption were not seen. Haematology, clinical chemistry and urinalysis conducted in all rats at the end of the exposure period, did not reveal any treatment-related abnormalities. No changes in absolute and relative (to body weight) organ weight were observed at the end of the exposure period. Furthermore, macroscopic examination at necropsy and histopathological examination of organs and tissues – including the full respiratory tract – did not reveal any treatment-related gross or microscopic changes

The high concentration level of 300 mg/m3 was considered to be the No-Observed- Adverse-Effect-Level (NOAEL) for sub-chronic inhalation exposure to Polyol IXOL® B350 in male and female rats.

Reference 2

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH
Further information is included as attachment in Section 13.

Reason / purpose for cross-reference:

read-across source

Dose descriptor:

NOAEC

Remarks:

local and systemic effects

Effect level:

300 mg/m³ air (analytical)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: No treatment-related effects observed at the highest concentration tested

Critical effects observed:

no

Conclusions:

Based on read-across from the structural analogue Polyol IXOL B350, no critical effects are to be expected for IXOL M125 after repeated inhalation exposure up to 300 mg/m3. Based on the available study, the NOAEC for local and systemic effects is 300 mg/m3, the highest concentration tested.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

300 mg/m³

Study duration:

subchronic

Species:

rat

Quality of whole database:

GLP compliant guideline study, klimisch 1

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

Study duration:

chronic

Species:

rat

Quality of whole database:

GLP compliant guideline study, klimisch 1

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

Oral Route:

No oral repeated dose toxicity studies are available for Polyol IXOL M125. Therefore, the information from the structural analogue Polyol IXOL B350 was used to evaluate the possible effects of Polyol IXOL M125 after repeated oral exposure.

For POLYOL IXOL B350, a GLP compliant Extended One-Generation Study is available in which Sprague Dawley rats were exposed daily by oral gavage to dose levels of 0, 75, 150 and 450 mg/kg bw/day. F0 males were treated 10 weeks prior to mating and throughout mating to termination (total of 128 to 131 days). F0 females were treated 10 weeks prior to mating and continued throughout mating, pregnancy and lactation until termination after the weaning of their litters(total of up to 113 to 127 days). Based on these results of this study, the no observed adverse effect level (NOAEL)of POLYOL IXOL B350 on fertility and development toxicity was found to be 450 mg/kg/day. 

Test item-related histopathological effects were observed in the liver, thyroid, and pituitary in F0 and F1 animals and in the kidney and heart of F0 animals. Adverse findings consisted of intratubular hemorrhage in the kidneys of F0 males administered 450 mg/kg/day and thyroid adenomas in F0 males administered ≥ 75 mg/kg/day, one F0 female administered 450 mg/kg/day, and one F1 male administered 75 mg/kg/day.

Test item-related changes on thyroid hormone included increased TSH in F0 and F1 males at ≥ 150 mg/kg/day and F1 females at 450 mg/kg/day, and decreased T4 in F0 males at ≥ 75 mg/kg/day, F1 males at ≥ 150 mg/kg/day and F1 females at ≥75 mg/kg/day. These changes correlated with thyroid hypertrophy/hyperplasia (non-adverse changes) in F0 and F1 males and females at ≥ 75 mg/kg/day and thyroid adenomas (adverse changes) in F0 males at ≥ 75 mg/kg/day, one F0 female at 450 mg/kg/day, and one F1 male at 75 mg/kg/day. Based on the thyroid gland adenomas, the NOAEL of POLYOL IXOL B350 on systemic toxicity was considered to be 150 mg/kg/day for F0 females, and 450 mg/kg/day for F1 females, and less than 75 mg/kg/day for F0 and F1 males. These thyroid findings (increase of TSH, decrease of T4, thyroid follicular hyperplasia and thyroid gland adenoma) could reflect a hypothyroidism induced by the test item. The test item used for the EOGRTS study contains perchlorate as impurity at 0.23% (w/w). Perchlorate is well-known to competitively inhibits uptake of iodine in the thyroid. The perchlorate anion interacts with the sodium-iodide symporter protein (NIS). As consequence a sustained inhibition of iodine uptake could cause depletion of thyroid stores of hormones T3 and T4 and lower thyroid hormone serum levels. Decrease in circulating levels of thyroid hormones, will trigger the hypothalamic-pituitary-thyroid (HPT) feedback pathway, resulting in an increase in secretion of TSH (thyroid stimulating hormone). Persistent stimulation of the thyroid gland by elevated levels of TSH results in increases in thyroid size and weight (goitre) (ATSDR, 2008a).

In the EOGRTS the rats were exposed to POLYOL IXOL B350 dose levels of 75, 150 and 450 mg/kg bw/day, corresponding to exposure levels of 0.17, 0.35 and 1.0 mg/kg bw/day based on the perchlorate anion. The NOAEL of < 75 mg/kg/day for systemic effects (thyroid adenomas) corresponds to 0.17 mg/kg/day for the perchlorate anion. For comparison, in a reliable 90 -day toxicity study with ammonium perchlorate a significant decrease of T3 and T4 levels was observed for both sexes at > 0.01 mg/kg/day while a significant increase of TSH was observed in males at > 0.2 mg/kg/day (Siglin et al, 2000). These effect levels correspond well with the effect levels observed in the EOGRTS study recalculated for perchlorate anion (decreased T4 in males at > 0.17 mg/kg and increased TSH in males and females at > 0.35 mg/kg). Based on the similarity of the thyroid findings (both qualitatively and quantitatively) in the EOGRTS with POLYOL IXOL B350 and the repeated dose toxicity studies with perchlorate, it can reasonably be assumed that the antithyroid findings observed in the EOGRTS are caused by the perchlorate anions present as impurity in the test substance and not by a direct effect of the test substance itself, respectively its main constituents. The in the EOGRTS with POLYOL IXOL B350 observed effects in the thyroid gland are to be considered to relate to an inhibited uptake of iodine by perchlorate anions.

Overall, the available animal studies for perchlorate consistently show antithyroid effects due to repeated perchlorate exposure leading to changes in levels of thyroid hormones and thyroid-stimulating hormone (TSH), thyroid weight increases, and histological findings in the thyroid (colloid depletion, follicular cell hypertrophy and hyperplasia) and goitre (EFSA 2015). However, whereas thyroid function and regulation are qualitatively similar in rats and humans (Bianco et al. 2002), important differences in serum thyroid hormone binding and clearance rates lead to important quantitative differences between the two species (NRC 2005): rats have more than 100 times lower serum thyroid hormone binding affinity contributing to higher thyroid hormone clearance rates and the need for a higher rate of thyroid hormone production per unit of body weight (Dohler et al. 1979). Therefore the potency of perchlorate is lower in humans than in animals, because of the substantial differences in the dynamics of the two systems (NRC 2005). This shows that based on the available data at comparable doses, rats are much more sensitive to disturbance of

thyroid homeostasis by perchlorates than are humans, so the relevance of rat studies - in quantitative terms - to humans is limited.

For this reason, the most critical effect of the substance after repeated oral exposure were effects on the kidney - intratubular hemorrhage in the kidneys of F0 males administered 450 mg/kg bw/day. Based on the available study, the NOAEL for systemic effects is 150 mg/kg bw/day.

Additionally, a GLP compliant 14-day dose range finding study is available with application via the oral route (Hongping Wan, 2014). The test substance was administered as a solution in 1% (w/v) Gum traganth powder in purified water by oral gavage to 4 groups of 16 male and 16 female Sprague-Dawley rats each, once a day. The control group was administered vehicle only for 14 consecutive days. The test article-treated groups were dosed at 417, 625, or 938 mg/kg/day for 14 consecutive days. There were no test article-related effects on clinical signs, body weight, food consumption, hematology, coagulation, or serum chemistry at any dose levels tested. Test article-related pathology changes were noted as enlarged liver in the males given ≥417 mg/kg/day, increased liver weights in both sexes given ≥417 mg/kg/day, and enlarged thyroid glands in the males given ≥417 mg/kg/day and females given ≥625 mg/kg/day. Based on the increased liver weights (females and males at all dose levels) and enlarged thyroid glands in males (males at all dose levels, females at mid and high dose), a LOAEL of 417 mg/kg bw/day was established.

Inhalation route:

One sub-acute inhalation toxicity study is available for Polyol IXOL M125. Since no sub-chronic studies are available for Polyol IXOL M125,information from the structural analogue Polyol IXOL B350 was used to evaluate the toxicity of Polyol IXOL M125 after sub-chronic exposure.

In a GLP compliant subacute repeated dose toxicity study, performed according to OECD guideline 412, Wistar rats (5/sex/dose) were treated with Polyol IXOL M125 (0, 0.1, 0.3, and 1 g/m3) for 6 hours/day, 5 days/week over a 28-day period, with a total of 20 exposure days (TNO Triskelion BV 2012). The concentration levels chosen for the 28-day study were based on the results of a 7-day range finding study. No treatment-related clinical abnormalities, differences in food consumption and body weight, and changes in haematology parameters were observed. Investigation of clinical chemistry parameters revealed a decreased plasma activity of alkaline phosphatase in females of the high concentration group. Absolute and relative weights of the kidneys and liver were statistically significantly increased in females of the high concentration group (liver weights could not be determined in males, because these organs were used for unscheduled DNA synthesis). Analysis of sperm parameters did not reveal any treatment-related abnormalities with respect to sperm morphology, motility and count. In addition, no organ weight changes or histopathological abnormalities were found in the male reproductive tissues. Macroscopic examination at necropsy did not show any treatment-related gross pathology. Microscopic examination revealed treatment-related changes in the larynx, consisting of focal, keratinizing squamous metaplasia in the epiglottis, accompanied by focal epithelial hyperplasia in some animals. The metaplasia was observed at all concentration levels, occurred in a concentration-dependent fashion with respect to incidence and severity, and reached statistical significance in males and females of the mid and high concentration groups. In conclusion, exposure to Polyol IXOL M 125 resulted in treatment-related local histopathological changes in the epiglottis at all concentration levels. Systemic changes upon exposure to Polyol IXOL M 125 were limited to increased kidney and liver weight in females of the high concentration group, accompanied by a decreased plasma activity of alkaline phosphatase. Therefore, the NOAEL for systemic effects of Polyol IXOL M 125 was considered to be 0.29 g/m3 for females and 0.95 g/m3.

The sub-chronic toxicity of Polyol IXOL® B350 (TNO, 2013) was studied in a 90-day inhalation toxicity study in Wistar rats. Four groups of 10 male and 10 female rats were exposed nose-only to target concentrations of 0 (control), 30, 100 or 300 mg/m3 Polyol IXOL® B350 for 6 hours/day, 5 days/week over a 14-week period, with a total of 65 exposure days. The animals were sacrificed on the day after the last exposure. To investigate the toxicity, data on clinical and neurobehavioural observations, ophthalmoscopy, body weight, food consumption, urinalysis haematology and clinical chemistry were collected. At necropsy, the animals were examined for gross macroscopic abnormalities, organs were weighed and a selection of organs and tissues (including the complete respiratory tract with nasal passages) was examined microscopically. The mean actual concentrations (± standard deviation) as measured by gravimetric analysis were very close to the target concentrations, i. e. 30.14 (± 3.21), 100.06 (± 4.54) and 300.70 (± 25.46) mg/m3 Polyol IXOL® B350 for the low, mid and high concentration groups, respectively. All animals survived until scheduled sacrifice. No treatment-related clinical or ophthalmoscopic abnormalities were observed in response to the exposure to Polyol IXOL® B350. Neurobehavioural observations (arena and Functional Observational Battery testing) and motor activity assessment did not indicate any neurotoxic potential of the test material. Treatment-related differences in growth or food consumption were not seen. Haematology, clinical chemistry and urinalysis conducted in all rats at the end of the exposure period, did not reveal any treatment-related abnormalities. No changes in absolute and relative (to body weight) organ weight were observed at the end of the exposure period. Furthermore, macroscopic examination at necropsy and histopathological examination of organs and tissues – including the full respiratory tract – did not reveal any treatment-related gross or microscopic changes. The high concentration level of 300 mg/m3 was considered to be the No-Observed- Adverse-Effect-Level (NOAEL) for sub-chronic inhalation exposure to Polyol IXOL® B350 in male and female rats.

Dermal route

For the dermal route, no data are available.

References:

ATSDR (2008a). Toxicological profile for Perchlorates, U.S. Department of Health and Human Services, Public Health Service, Atlanta, GA

Bianco et al. (2002). Biochemistry, cellular and molecular biology, and physiological roles of the iodothyronine selenodeiodinases. Endocr. Rev. 2002; 23: 38 -89

BAuA (2016). Substance Evaluation Conculsion as required by REACH Article 48 and Evaluation Report for Sodium Perchlorate. Evaluating Member State: Germany. 10 August 2016.

Dohler KD, Wong CC and von zur Muhlen A (1979). The rat as model for the study of drug effects on thyroid function: consideration of methodological problems. Pharmacology & therapeutics Part B: General & systematic pharmacology 5:305-318

EFSA (2015).Scientific Opinion on the risks to public health related to the presence of perchlorate in food, in particular fruits and vegetable

NRC (National Research Council), 2005. Health implications of perchlorate ingestion. National Academics Press, Washington DC, 2005

Siglin JC, Mattie DR, Dodd DE, Hildebrandt PK and Baker WH, 2000. A 90 -day drinking water toxicity study in rats of the environmental contaminant ammonium perchlorate. Toxicological Sciences 57, 61 -74.

Justification for classification or non-classification

In the 28-day inhalation toxicity study, microscopic examination revealed treatment-related changes in the larynx, consisting of focal, keratinizing squamous metaplasia in the epiglottis, accompanied by focal epithelial hyperplasia in some animals. These effects can be considered as adaptive responses and they did not result in functional changes.This is confirmed by the absence of these effects in the 90-day inhalation toxicity study with the structural analogue Polyol IXOL B350 in which no treatment-related changes were observed in any of the parameters tested. Therefore the high concentration level of 300 mg/m3 was considered to be the No-Observed-Adverse-Effect-Level (NOAEL) for sub-chronic inhalation exposure in male and female rat.

In the Extended One-Generation Toxicity study with the structural analogue Polyol IXOL B350, test item-related changes on thyroid hormone included increased TSH in F0 and F1 males at ≥ 150 mg/kg/day and F1 females at 450 mg/kg/day, and decreased T4 in F0 males at ≥ 75 mg/kg/day, F1 males at ≥ 150 mg/kg/day and F1 females at ≥75 mg/kg/day. These changes correlated with thyroid hypertrophy/hyperplasia (non-adverse changes) in F0 and F1 males and females at ≥ 75 mg/kg/day and thyroid adenomas (adverse changes) in F0 males at ≥ 75 mg/kg/day, one F0 female at 450 mg/kg/day, and one F1 male at 75 mg/kg/day. Based on the thyroid gland adenomas, the NOAEL of POLYOL IXOL B350 on systemic toxicity was considered to be 150 mg/kg/day for F0 females, and 450 mg/kg/day for F1 females, and less than 75 mg/kg/day for F0 and F1 males. Based on a NOAEL of < 75 mg/kg/day, a classification of POLYOL IXOL B350 as STOT RE 2; H373 (oral route, affected organ: thyroid) would be warranted.

However, the antithyroid findings observed in the EOGRTS can be correlated with the presence of perchlorate anions as impurity (0.23% w/w) in the test substance used for the EOGRTS since perchlorate is well-known to competitively inhibits the update of iodine in the thyroid. Based on the available data at comparable doses it is known that rats are much more sensitive to disturbance of thyroid homeostasis by perchlorates than are humans, so the relevance of rat studies - in quantitative terms - to humans is limited. For this reason, the most critical effect of the substance after repeated oral exposure were effects on the kidney - intratubular hemorrhage in the kidneys of F0 males administered 450 mg/kg bw/day. Based on the available study, the NOAEL for systemic effects is 150 mg/kg bw/day.  

According to the Guidance on the Application of the CLP Criteria, chapter 3.9.2.3.2 “Any information pertaining to the relevance of findings in animals to humans must be taken into account and may be used to modify the classification from how it would be if based on the available animal data. For instance, it may be shown that the findings in animals are not relevant for humans, for example if the toxicity in animals is mediated by a mode of action that does not occur in humans. This would potentially provide a supporting case for no classification (CLP Guidance 2015)".

The availability of sufficient human data on thyroid toxicity of perchlorate leads to a classification of the substance sodium perchlorate as STOT RE 2; H373 (affected organ: thyroid). Since sodium perchlorate is present as impurity at a maximum concentration of 0.5% (w/w) and the accounted NOAEL for POLYOL IXOL B350 is 150 mg/kg bw/day based on kidney effects at 450 mg/kg bw/day based, a classification as STOT RE 2 is not warranted for POLYOL IXOL B350. Since similar concentrations of perchloric acid were found in both target and source substance, the same conclusion for STOT RE classification is valid for Polyol IXOL M125.