2,2'-ethylenedioxydiethyl dimethacrylate

Endpoint summary

Description of key information

Subacute (33-40 day) study; oral (gavage); rat, OECD 422, GLP: NOAEL = 1000 mg/kg bw/d
Subacute (14 day), subchronic (90 day) and chronic (78 weeks) studies; dermal; mouse, m (no specific guideline, GLP): no systemic toxicity, local irritation at the site of application

Data from the metabolites after rapid hydrolysis

TREG: Subchronic (90d) study, oral, feeding, rat, OECD 408, GLP: NOAEL 1522 mg/kg bw/d males & 1622 mg/kg bw/d females

MAA: Subchronic (90d) study, inhalation, rat, OECD 408, GLP: NOAEC local & systemic 100 ppm = 352 mg/m3

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 April 2012-16 June 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 22 March 1996

Deviations:

no

GLP compliance:

yes

Limit test:

no

Specific details on test material used for the study:

Name: Triethyleneglycol dimethacrylate

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source:Hsd: Sprague Dawley SD rats from Harlan Italy s.r.l., San Pietro al Natisone (UD), Italy
- Age at study initiation: 7 to 8 weeks old and weighing 200-204g for males and 178-179g for females.
- Weight at study initiation: (P) Males: 297- 361g; Females:208-255g;
- Fasting period before study:no
- Housing:5sex/cage
- Diet (e.g. ad libitum):ad libitum throughout the study, except during clinical pathology investigations
- Water (e.g. ad libitum):d libitum throughout the study, except during clinical pathology investigations - Males only. Ad libitum for females
- Acclimation period:18 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C):22+/-2
- Humidity (%):55+/-15
- Air changes (per hr):There were approximately 15 to 20 air changes per hour
- Photoperiod (hrs dark / hrs light):rooms were lit by artificial light for 12 hours each day

IN-LIFE DATES: From: To:05 April 2012 to 16 June 2012

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: The dosing formulations were prepared daily

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Before the start of treatment, analysis was performed to confirm that the proposed formulation procedure was acceptable and that the stability of the formulation was satisfactory. Samples of the formulations prepared during the study were also analysed to check the homogeneity and concentration.
Chemical analysis was carried out by the Analytical Chemistry Department at RTC

Duration of treatment / exposure:

Males were treated for a total of 5 weeks (2 weeks before pairing and 3 weeks during the paring period). Females were treated for approximately 6 weeks (2 weeks before pairing, 3 weeks of gestation until post partum Day 3).

Frequency of treatment:

Daily

Dose / conc.:

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

Dose / conc.:

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

Dose / conc.:

1 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

10/sex/dose

Control animals:

yes

Details on study design:

- Dose selection rationale:
Dose levels of 100, 300 and 1000 mg/kg/day were selected in consultation with the Sponsor based on information from preliminary studies.

Observations and examinations performed and frequency:

Mortality

Throughout the study, all animals were checked early in the morning and in the afternoon. At
weekends and Public Holidays a similar procedure was followed except that the final check
was carried out at approximately mid-day. This allowed post mortem examinations to be
carried out during the working period of that day.

Clinical signs

All observations were recorded for individual animals.
Examination of individual animals for signs of reaction to treatment was carried out daily
prior to dosing and at suitable intervals after dosing. The number and timing of these daily
observations were reviewed by the Study Director at the end of the first week of treatment.

Clinical observations (Functional Observation Battery Tests)

Once before commencement of treatment and at least once a week thereafter, each animal
was given a detailed clinical examination. Each animal was removed from the home cage
and observed in an open arena. The tests included observation of changes in gait and posture,
reactivity to handling, presence of clonic or tonic movements, stereotypies or bizarre
behaviour and effects on the autonomic nervous system (e.g. lachrymation, piloerection,
pupil size, unusual respiratory pattern).
Grip strength and sensory reactivity to stimuli

Once during the study, towards the end of treatment, 5 males and 5 females were randomly
selected from each group for evaluation of sensory reactivity to stimuli of different
modalities (e.g. auditory, visual and proprioceptive stimuli) and for assessment of grip
strength. Measurements were performed using a computer generated random order.

Motor activity assessment (MA)

Once during the study, towards the end of treatment, 5 males and 5 females were randomly
selected from each group and the motor activity was measured (for approximately 5 minutes)
by an automated activity recording device. Measurements were performed using a computer
generated random order.

Food consumption

The weight of food consumed by each cage of males and females was recorded weekly
during the pre-mating period starting from allocation. Individual food consumption for the
females was measured on gestation Days 7, 14 and 20 starting from Day 0 post coitum and
on Day 4 post partum starting from Day 1 post partum.

Body weight

Males were weighed weekly from allocation to termination.
Females were weighed weekly from allocation to pairing and on gestation Days 0, 7, 14 and
20. Dams were also weighed on Days 1 and 4 post partum.
Clinical pathology investigations

As a part of the sacrificial procedure, samples of blood were withdrawn under isofluorane
anaesthesia from the abdominal vena cava from 5 males and 5 females (females with viable
litters, if possible) randomly selected from each group, under condition of food deprivation.
The blood samples collected were divided into tubes as follows:

EDTA anticoagulant for haematological investigations
Heparin anticoagulant for biochemical tests
Citrate anticoagulant for coagulation tests
The measurements performed on blood samples are listed below:

Haematology

Haematocrit
Haemoglobin
Red blood cell count
Reticulocyte count
Mean red blood cell volume
Mean corpuscular haemoglobin
Mean corpuscular haemoglobin concentration
White blood cell count
Differential leucocyte count - Neutrophils
- Lymphocytes
- Eosinophils
- Basophils
- Monocytes
- Large unstained cells
- Platelets
- Prothrombin time
Clinical chemistry

Alkaline phosphatase
Alanine aminotransferase
Aspartate aminotransferase
Gamma-glutamyltransferase
Urea
Creatinine
Glucose
Triglycerides
Bile acids
Phosphorus
Total bilirubin
Total cholesterol
Total protein
Albumin
Globulin
A/G Ratio
Sodium
Potassium
Calcium
Chloride
Urinalysis (Only males)

At the same time interval as the clinical pathology investigations, individual overnight urine
samples were also collected from the same animals under the same conditions. Before
starting urine collection, water bottles were removed from each cage and each animal
received approximately 10 mL/kg of drinking water by gavage, in order to obtain urine
samples suitable for analysis.

Appearance
Volume
Specific gravity
pH
Protein
Glucose
Ketones
Bilirubin
Urobilinogen
Blood

The sediment, obtained from centrifugation at approximately 3000 rpm for 10 minutes, was
examined microscopically for:

Epithelial cells
Leucocytes
Erythrocytes
Crystals
Spermatozoa and precursors
Other abnormal components

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Other examinations:

Males were treated for 2 weeks prior to pairing and during pairing with females until the day before necropsy, for a total of 35/37 days.
Females were treated for 2 weeks prior to pairing, during pairing and throughout the gestation and lactation periods until Day 3 post partum or the day before necropsy.
The following investigations were performed in all groups: body weight, clinical signs (including neurotoxicity assessment, motor activity and sensory reaction to stimuli), food consumption, oestrous cycle, mating performance, clinical pathology investigations (haematology, clinical chemistry and males urinalysis), litter weight, pups observations, macroscopic observations and organ weights.
External examination for pups at Day 4 of lactation and external and internal examination in pups found dead were also performed.

The histopathological examination was performed on control and high dose groups (five males and five females randomly selected). The examination included also the identification of the stages of the spermatogenic cycle.

Statistics:

Means and standard deviations were calculated as appropriate. For body weight, body weight gain, food consumption, clinical pathology, sensory reaction to stimuli and motor activity, terminal body weight and organ weights (absolute and relative) the significance of the differences amongst group means was assessed by Dunnett’s test or a modified t test, depending on the homogeneity of data.
The non-parametric Kruskal-Wallis analysis of variance was used for all the other parameters. The criterion for statistical significance was p<0.05.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Statistically significant reduction in body weight was noted in high dose males compared to controls from Day 15 of treatment to sacrifice.

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

Bile acids showed an increase in almost all treated females. Changes were 40% to 156% and were dose-related.

Urinalysis findings:

no effects observed

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

A slight increase in absolute and relative liver weight was observed high dose females compared to controls.

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

Although changes in body weight gain of high dose males, bile acids and liver weight of high dose females were observed and since the microscopic examination revealed no lesion in any organs, the dosage of 1000 mg/kg bw/day is considered the NOAEL for this study.

Dose descriptor:

NOAEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: no adverse effects observed

Critical effects observed:

no

A total of 10 females were proved not pregnant at necropsy: 4 females in the control group, 2 in the low dose group (including one female which did not mate), 2 in the mid-dose group and 2 in the high dose group. One control female showed unilateral total resorption. All remaining females gave birth and the number of dams with litters per group were: 5 in the control and 8 each in the remaining treated groups.

Clinical signsand clinical observations (Functional ObservationBatteryTests)

Clinical signs and functional observation battery tests were unaffected by treatment.

Body weight and body weight gain

Statistically significant reduction in body weight was noted in high dose males compared to controls from Day 15 of treatment to sacrifice.

Food consumption

No effects on food consumption were observed.

Motor activity and sensory reactivity to stimuli

No differences of toxicological significance were seen.

Haematology

No changes of toxicological significance were seen. No changes were recorded for coagulation parameters.

Clinical chemistry

Bile acids showed an increase in almost all treated females.

Urinalysis – males only

No changes were observed.

Oestrus cycle, reproductive parameters, pairing combination and mating performance

No treatment related changes were seen.

Implantation, pre-birth loss data and gestation length of females

No treatment-related effects were seen.

Litter data and sex ratio of pups

Litter data and sex ratios were unaffected by treatment.

Clinical signs of pups

Clinical signs were comparable between treated and control groups.

Necropsy findings in decedent pups and in pups sacrificed on Day 4post partum

No treatment-related effects were seen.

Terminal body weight and organ weights

A slight increase in absolute and relative liver weight was observed high dose females compared to controls.

Macroscopic observations

No relevant changes were detected at post mortem examination in treated animals, when compared with controls.

Microscopic observations

No treatment-related changes were seen in selected organs/tissues evaluated in males or females receiving Triethyleneglycol dimethacrylate nor in the abnormalities detected in all groups at post mortem including the staging in the spermatogenic cycle.

Conclusions:

Although changes in body weight gain of high dose males, bile acids and liver weight of high dose females were observed and since the microscopic examination revealed no lesion in any organs, the dosage of 1000 mg/kg bw/day is considered to be the NOAEL for this study.

Executive summary:

In a Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test according to OECD Guideline 422 (22 March 1996) TREGDMA was administered to 10 Hsd: Sprague Dawley SD rats/sex/dose orally by gavage at dose levels of 0 (control), 100, 300 and 1000 mg/kg bw/d. The treatment schedule included 2 weeks before pairing, during pairing, post coitum and post partum periods up to day 3 post partum. Animals were administered for approximately 5 and 8 weeks for males and females, respectively.  

No mortality occurred in the study. No clinical signs of toxicological significance were reported. Statistically significant reduction in body weight was noted in high dose males compared to controls from Day 15 of treatment to sacrifice; body weights of females were unaffected by treatment.

Food consumption was comparable between the control and treated groups.

No differences in motor activity, grip strength and sensory reactivity to stimuli were observed. The differences noted in land foot splay noted in low dose males and females were considered incidental since they were inconsistent between males (increase) and females (reduction) and without any dose correlation.

In haematology and urinanalysis no changes of toxicological significance were seen. The statistically significant decrease of reticulocytes recorded in females dosed with 1000 mg/kg bw/d was considered of no toxicological relevance since no associated alterations of the erythrocytes were observed. No changes in prothrombine time were noted. Bile acids showed a dose-related increase in almost all treated females. No other changes of toxicological significance were observed. Two males of the high dose group showed an increase of urea (mean value 35% above controls). However, due to the low incidence, this finding cannot be conclusively attributed to treatment.

Other statistically significant fluctuations of some biochemical parameters were recorded in treated animals, such as: chloride, calcium, sodium and potassium. Changes were of minimal magnitude, not consistent between sexes and/or not dose-related, therefore considered incidental.

All females mated with the exception of on female of the low dose group. Two females, 1 in the low dose group and 1 in the mid-dose group showed an irregular cycle (oestrus was never observed); the low dose female did not mate, the mid-dose female was found sperm positive after 8 days of paring but not pregnant at necropsy. These isolated cases were considered incidental. In the control group a total of 5 females were found not pregnant and 1 female had unilateral implantation with total resorption. In addition, 1 female in the low dose group, 2 females in the mid-dose group and 2 females in the high dose group were not pregnant.

Measurements of copulatory index, fertility index Pre-coital interval and the number of copulation plugs did not show differences between treated and control groups. No significant differences were observed in the number of implantation, corpora lutea, total litter size, pre-implantation loss, pre-birth loss and gestation length between control and treated groups.

Litter data and sex ratios were unaffected by treatment. Clinical signs of pups were comparable between groups. Decedent pups were found in all groups without dose relationship. Necropsy findings in decedent pups and in pups sacrificed on Day 4post partumdid not reveal any treatment-related effect.

A slight reduction in terminal body weight was noted in the mid- and high dose males (statistically significant in high dose). Terminal body weight of females was unaffected by treatment. A slight increase in absolute and relative liver weight was observed in high dose females compared to controls. No relevant changes were detected at post mortem examination in treated animals, when compared with controls.

No treatment-related changes were seen in selected organs/tissues evaluated in males or females nor in the abnormalities detected in all groups at post mortem including the staging in the spermatogenic cycle.

Although changes in body weight gain of high dose males, bile acids and liver weight of high dose females were observed and since the microscopic examination revealed no lesion in any organs, the dosage of 1000 mg/kg bw/d is considered to be the NOAEL for this study.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Read across from the methacrylic metabolite
REPORTING FORMAT FOR THE ANALOGUE APPROACH
see attached category document

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
see attached category document, chapter 1.1ff

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
see attached category document, chapter 1

3. ANALOGUE APPROACH JUSTIFICATION
see attached category document, chapter 5 (Toxikokinetics) and endpoint specific chapters

4. DATA MATRIX
see attached category document, table in chapter 1.2 and endpoint specific chapters

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Age when supplied; sex: about 7 weeks, male and female
Supplier: Charles River Laboratories, Research Models and Services, Germany GmbH; Sandhofer Weg 7, 97633 Sulzfeld
During the period when the rats were not exposed they were housed singly in wire cages (type DK III, Becker & Co., Castrop-Rauxel, FRG (floor area about 800 cm²)). Underneath the cages, waste trays were fixed containing bedding material (Type Lignocel FS14 fibres,
dustfree bedding supplied by SSNIFF, Soest, Germany)
The motor activity measurements were conducted in Polycarbonate cages with wire covers from Ehret, Emmendingen, FRG (floor area about 800 cm²) and bedding.
The animals were kept in fully air-conditioned rooms in which a temperature in the range of 20 - 24°C and relative humidity in the range of 30 - 70% were ensured by means of a central air-conditioning system.
A light/dark rhythm of 12 hours was maintained.
The room was completely disinfected using a disinfector ("AUTEX", fully automatic, formalinammonia-based terminal disinfector) before the start of the study. Usually, each week the floor and the walls were cleaned with water containing about 1 % Mikroquat®.
The animals were maintained on milled mouse/rat laboratory diet “GLP”, (Provimi Kliba SA, Kaiseraugst, Basel Switzerland) and tap water ad libitum.

Route of administration:

inhalation

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

For each concentration, the test substance was supplied to the two-component atomizer of a thermostated vaporizer at a constant rate by means of the piston metering pump. The vapor was generated by spraying the substance with compressed air into a counter current of conditioned supply air (about 50% ± 20% relative humidity, 22°C ± 2°C). Thereafter it was further mixed with conditioned supply air and passed into the inhalation system.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentrations of the inhalation atmospheres in test groups 1 - 4 were analyzed by HPLC.

Duration of treatment / exposure:

90 days

Frequency of treatment:

6 hours/day, 5 days/week

Dose / conc.:

20 ppm

Remarks:

= 70 mg/m3

Dose / conc.:

40 ppm

Remarks:

= 141 mg/m³

Dose / conc.:

100 ppm

Remarks:

= 352 mg/m³

Dose / conc.:

350 ppm

Remarks:

= 1232 mg/m³

No. of animals per sex per dose:

10/sex/dose

Control animals:

yes, sham-exposed

Details on study design:

Ten male and ten female Sprague Dawley rats per test group were whole body exposed to a vapor of the test substance on 6 hours per working day for 90 days (65 exposures). The target concentrations were 20, 40, 100 and 350 ppm (corresponding to 70, 141, 352 and 1232 mg/m3). A concurrent control group was exposed to conditioned air.

Observations and examinations performed and frequency:

The animals were examined for evident signs of toxicity or mortality twice a day (in the morning and in the late afternoon) from Mondays to Fridays and once a day (in the morning) on Saturdays, Sundays and public holidays. The clinical condition of the test animals was recorded once during the preflow period and on post-exposure observation days and at least 3 times (before, during and after exposure) on exposure days.
During exposure only a group wise examination was possible.The body weight of the animals was determined at the start of the preflow, at the start of the exposure period and then, as a rule, once a week as well as one day prior to gross necropsy. As a rule, the animals were weighed at the same time of the day.
Body weight change was calculated as the difference between body weight on the respective exposure day and body weight on the day of the first exposure. Group means were derived from the individual differences.
Food consumption was determined weekly and calculated as mean food consumption in grams per animal and day.Food efficiency (group means) was calculated based upon individual values for body weight and food consumption.
Before the start of the exposure period (day -6) the eyes of all animals, and at the end of the study (day 82) the eyes of the animals of test group 0 (control group) and test group 4 (high concentration) were examined with an ophthalmoscope (HEINE Optotechnik, Herrsching, FRG)) for any changes in the refracting media.
Functional observation battery (FOB) was carried out on the assigned animals once before the exposure period and once against the end of the exposure period.Motor activity was measured on the same day and with the same animals as FOB was performed.

Sacrifice and pathology:

In the morning, blood was taken from the retro-orbital venous plexus from fasted animals. The animals were anaesthetized using isoflurane (Isoba®, Essex GmbH Munich, Germany). The blood sampling procedure and the subsequent analysis of the blood and serum samples were carried out in a randomized sequence. For urinalysis the individual animals were transferred to metabolism cages (withdrawal of food and water) and urine was collected overnight. The urine samples were evaluated in a randomized sequence. At necropsy specimen were sampled from fasted anesthetized male animals in a randomized sequence for sperm analyses.
Hematological parameters were determined in blood with EDTA-K3 as anticoagulant using a particle counter (Advia 120 model; Bayer, Fernwald, Germany): Furthermore differential blood smears were prepared and stained according to Wright without being evaluated.
An automatic analyzer (Hitachi 917; Roche, Mannheim, Germany) was used to examine the clinicochemical parameters.
With the exception of volume, color, turbidity, sediment examination and the specific gravity, all the urine constituents were determined semi-quantitatively using test strips (Combur-9-test M, Roche, Mannheim, Germany) and a reflection photometer (Miditron M; Roche, Mannheim, Germany).
Immediately after necropsy and organ weight determination the right testis and cauda epididymis were taken from all male animals.
Sperm motility examinations were carried out in a randomized sequence. Sperm morphology and sperm head count (cauda epididymis and testis) were evaluated for the control and highest dose group, only.
The animals were killed under Narcoren anesthesia by exsanguination from the abdominal aorta and vena cava. The animals were then be necropsied and subjected to a grosspathological assessment. Animals that died intercurrently or were killed in a moribund state were necropsied and assessed by gross-pathology as quickly as possible.

Statistics:

DUNNETT, C.W. (1955): A multiple comparison procedure for comparing several treatments with a control. JASA, Vol. 50, 1096– 1121
DUNNETT, C.W. (1964). New tables for multiple comparisons with a control. Biometrics, Vol. 20, 482 –491
SIEGEL, S. (1956): Non-parametric statistics for the behavioural sciences. McGraw-Hill New York
Nijenhuis, A.; Wilf, H.S.(1978): Combinatorial Algorithms. AcademicPress New York, 32-33
Hettmansperger, T.P. ( 1984); Statistical Inference based on Ranks. John Wiley & Sons New York, 132-142
International Mathematical and Statistical Libraries, Inc., 2500 Park West Tower One, Houston, Texas 77042-3020, USA, nakl-1 -nakl-3
MILLER, R.G. (1981): Simultaneous Statistical Inference Springer-Verlag New York Inc., 165-167

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Details on results:

Subchronic vapor inhalation of the test substance led to the following treatment-related
adverse effects:
Test group 4 (350 ppm):
􀂾 Decreased body weight of the males (- 6.1% to - 12.8%) from study day 7 onward
􀂾 Decreased body weight change (gain) of the males (- 28.5% to - 64.8%) from study
day 7 onward
􀂾 Decreased food consumption in the male animals on study days 7 (- 13.5%),
14 (- 12.2%), and from study day 28 through to day 84 (from - 9.4% to - 13.7%)
􀂾 Decreased food efficiency in the male animals on study days 7, 28, 49 and 56
􀂾 Decrease of terminal body weights in both sexes
􀂾 Goblet cell hypertrophy/hyperplasia in the respiratory epithelium of the nasal cavity
(level I) of two females
Test group 1 (20 ppm), test group 2 (40 ppm) and test group 3 (100 ppm):
􀂾 No treatment-related findings

Dose descriptor:

NOAEC

Remarks:

systemic effects

Effect level:

100 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

food efficiency

Remarks on result:

other: = 352 mg/3

Dose descriptor:

NOAEC

Remarks:

local effects

Effect level:

100 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

Remarks on result:

other:

Remarks:

= 352 mg/3

Dose descriptor:

LOAEC

Effect level:

350 ppm

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

food efficiency

Remarks on result:

other: = 1232 mg/m3

Dose descriptor:

LOAEC

Remarks:

local effets

Effect level:

350 ppm

Based on:

test mat.

Sex:

female

Basis for effect level:

histopathology: non-neoplastic

Remarks on result:

other: = 1232 mg/m3

Critical effects observed:

not specified

Conclusions:

In a valid guideline study, the the no-observed adverse effect level (NOAEL) is 100 ppm for the male and female rats exposed by whole body inhalation for 90 days.

Executive summary:

In a valid guideline study acc OECD 413 ( Subchronic inhalation toxicity: 90 day exposure of rats) methacrylic acid induced signs of general toxicity as indicated by descreased body weight, body weight gain, food consumption and transiently food efficiency in the high concentration male animals. At a concentration as high as 350 ppm (1232 mg/m³), the local irritating effect was marginal, indicated by the hypertrophy/hyperplasia of the respiratory epithelium in the nasal cavity of two female animals. Substance-related changes of the sexual organs were not noted in any of the exposed animals, nor were there any changes of sperm mobility and sperm head counts. Under the current test conditions, the no-observed adverse effect level (NOAEL) in this study is 100 ppm (352 mg/m³) for the male and female rats.

NOTE: Any of data in this dataset are disseminated by the European Union on a right-to-know basis and this is not a publication in the same sense as a book or an article in a journal. The right of ownership in any part of this information is reserved by the data owner(s). The use of this information for any other, e.g. commercial purpose is strictly reserved to the data owners and those persons or legal entities having paid the respective access fee for the intended purpose.

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

subchronic study according to EPA Dermal Bioassay Workshops (April 28-29, 1987 and May 18-19, 1988).

GLP compliance:

yes

Limit test:

no

Specific details on test material used for the study:

- Name of test material (as cited in study report): triethylene glycol dimethacrylate

Species:

mouse

Strain:

other: C3H/HeNHsd

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Sprague-Dawley (Indianapolis, IN)
- Housing: individually
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 2-3 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 65-77
- Humidity (%): 40-70%
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

open

Vehicle:

acetone

Details on exposure:

TEST SITE
applied to the clipped interscapular region of the back
- Type of wrap if used: no wrap
- Time intervals for shavings or clipplings: during the week prior to the first dose and as needed during the dosing period, the fur was clipped from the dorsal area of the trunk

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50 µL
- Concentration (if solution): 5, 25, 50, 100%

USE OF RESTRAINERS FOR PREVENTING INGESTION: no

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

5 d/week

Dose / conc.:

100 mg/kg bw/day

Remarks:

= 5 %

Dose / conc.:

500 mg/kg bw/day

Remarks:

= 25 %

Dose / conc.:

1 000 mg/kg bw/day

Remarks:

= 50 %

Dose / conc.:

2 000 mg/kg bw/day

Remarks:

= 100 %

No. of animals per sex per dose:

10 males

Control animals:

yes, concurrent no treatment

yes, concurrent vehicle

Observations and examinations performed and frequency:

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: weekly starting 1 week before dosing

BODY WEIGHT: Yes
- Time schedule for examinations: weekly starting 1 week before dosing

HAEMATOLOGY: Yes
- Time schedule for collection of blood: prior to sacrifice
- How many animals: 5/group

NECROPSY: YES


ORGAN WEIGHTS: YES
-liver, kidneys, spleen, brain and testes were weighed.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: prior to sacrifice
- How many animals: 5/group

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: weekly starting 1 week before dosing
- Dose groups that were examined: all groups
- Battery of functions tested: observation in an open arena and the following endpoints were evaluated: stereotypy, arousal, approach response, startle response, tail pinch, salivation, Iacrimation, mouthbreathing, piloerection, gait, muscle tone, air righting reflex, convulsions, tremors, and diarrhea

OTHER: cutaneous cell proliferation evaluations using the PCNA procedure in 5/test group and 10/control group

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes (high dose group; Iungs, liver, kidneys, spleen, stomach, and gross lesions in all dose groups)

Other examinations:

Proliferating cell nuclear antigen (PCNA) immunohistochemical analysis

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

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):

inreased liver weights in 50 and 100% groups, but no clinical or histopathological evidence of liver toxicity

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

no other than dermal effects

Histopathological findings: neoplastic:

not examined

Dose descriptor:

NOAEL

Remarks:

local

Effect level:

100 mg/kg bw/day

Based on:

act. ingr.

Sex:

male

Basis for effect level:

other: acanthosis, hyperkeratosis

Remarks on result:

other: = 5%

Dose descriptor:

NOAEL

Remarks:

systemic

Effect level:

2 000 mg/kg bw/day

Based on:

act. ingr.

Sex:

male

Remarks on result:

other: = 100%; no relevant systemic effects observed

Critical effects observed:

not specified

For TREGDMA-treated animals, exfoliation/desquamation was observed in all animals of the 25, 50 and 100% dose groups at some time during the study. Ulceration and excoriation also were seen in a few animals from these groups that resolved by day 35. No findings were recorded in the 5% dose group.

Hyperkeratosis was observed in all animals from the 25, 50, and 100% dose groups and acanthosis was observed in 80 or 100% of the animals from these groups. A single animal was diagnosed with dermatitis from the 100% group. Grading of these lesions generally correlated with dose. No microscopic changes of the skin were noted for the 5% dosage.

Skin basal cell proliferation (PCNA assay) was increased in the 25, 50, and 100% groups, but statistically significant only in the 100% group.

Conclusions:

The 13 week-NOAEL of TREGDMA in mice for local effects (acanthosis, hyperkeratosis) was 5% in acetone (approx. 100 mg/kg bw/d). The 13 week-NOAEL for systemic effects was 100% (approx. 2000 mg/kg bw/d).

Executive summary:

In a 13 weeks dermal toxicity study, TREGDMA (91% a.i.) was applied to the clipped interscapular region of the back of 10 maleC3H/HeNHsd mice/dose at dose levels of 0 (control), 5, 25, 50 and 100% TREGDMA in acetone, corresponding to approx. 100, 500, 1000 and 2000 mg/kg bw/d. The doses were applied in 50 µL/animal/day 5 days per week.

During the treatment phase of the study, no effects were observed except for skin lesions at the site of treatment. Exfoliation and desquamation was observed in all animals of the 25, 50 and 100% dose groups at some time during the study. Ulceration and excoriation also were seen in a few animals from these groups that resolved by day 35. No findings were recorded in the 5% dose group.

The only treatment-related finding at necropsy, other than for treated skin, was an increase in liver weight of approx. 7 and 10% compared with the control group in the 50 and 100% groups, respectively. There was no clinical or histopathological evidence of liver toxicity, thus the etiology and biological significance of the increased weight was uncertain.

Hyperkeratosis was observed in all animals from the 25, 50, and 100% dose groups and acanthosis was observed in 80 or 100% of the animals from these groups. A single animal of the 100% group was diagnosed with dermatitis. No microscopic changes of the skin were noted for the 5% dosage.

Skin basal cell proliferation (PCNA assay) was increased in the 25, 50, and 100% groups, but was statistically significant only in the 100% group.

In this study, the 13 week-NOAEL of TREGDMA for local effects (acanthosis, hyperkeratosis) was 5% (approx. 100 mg/kg bw/d). The 13 week-NOAEL for systemic effects was 100% (approx. 2000 mg/kg bw/d).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

2 000 mg/kg bw/day

Study duration:

subchronic

Species:

mouse

Repeated dose toxicity: dermal - local effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

subchronic study according to EPA Dermal Bioassay Workshops (April 28-29, 1987 and May 18-19, 1988).

GLP compliance:

yes

Limit test:

no

Specific details on test material used for the study:

- Name of test material (as cited in study report): triethylene glycol dimethacrylate

Species:

mouse

Strain:

other: C3H/HeNHsd

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Sprague-Dawley (Indianapolis, IN)
- Housing: individually
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 2-3 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 65-77
- Humidity (%): 40-70%
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

open

Vehicle:

acetone

Details on exposure:

TEST SITE
applied to the clipped interscapular region of the back
- Type of wrap if used: no wrap
- Time intervals for shavings or clipplings: during the week prior to the first dose and as needed during the dosing period, the fur was clipped from the dorsal area of the trunk

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50 µL
- Concentration (if solution): 5, 25, 50, 100%

USE OF RESTRAINERS FOR PREVENTING INGESTION: no

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

5 d/week

Dose / conc.:

100 mg/kg bw/day

Remarks:

= 5 %

Dose / conc.:

500 mg/kg bw/day

Remarks:

= 25 %

Dose / conc.:

1 000 mg/kg bw/day

Remarks:

= 50 %

Dose / conc.:

2 000 mg/kg bw/day

Remarks:

= 100 %

No. of animals per sex per dose:

10 males

Control animals:

yes, concurrent no treatment

yes, concurrent vehicle

Observations and examinations performed and frequency:

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: weekly starting 1 week before dosing

BODY WEIGHT: Yes
- Time schedule for examinations: weekly starting 1 week before dosing

HAEMATOLOGY: Yes
- Time schedule for collection of blood: prior to sacrifice
- How many animals: 5/group

NECROPSY: YES


ORGAN WEIGHTS: YES
-liver, kidneys, spleen, brain and testes were weighed.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: prior to sacrifice
- How many animals: 5/group

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: weekly starting 1 week before dosing
- Dose groups that were examined: all groups
- Battery of functions tested: observation in an open arena and the following endpoints were evaluated: stereotypy, arousal, approach response, startle response, tail pinch, salivation, Iacrimation, mouthbreathing, piloerection, gait, muscle tone, air righting reflex, convulsions, tremors, and diarrhea

OTHER: cutaneous cell proliferation evaluations using the PCNA procedure in 5/test group and 10/control group

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes (high dose group; Iungs, liver, kidneys, spleen, stomach, and gross lesions in all dose groups)

Other examinations:

Proliferating cell nuclear antigen (PCNA) immunohistochemical analysis

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

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):

inreased liver weights in 50 and 100% groups, but no clinical or histopathological evidence of liver toxicity

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

no other than dermal effects

Histopathological findings: neoplastic:

not examined

Dose descriptor:

NOAEL

Remarks:

local

Effect level:

100 mg/kg bw/day

Based on:

act. ingr.

Sex:

male

Basis for effect level:

other: acanthosis, hyperkeratosis

Remarks on result:

other: = 5%

Dose descriptor:

NOAEL

Remarks:

systemic

Effect level:

2 000 mg/kg bw/day

Based on:

act. ingr.

Sex:

male

Remarks on result:

other: = 100%; no relevant systemic effects observed

Critical effects observed:

not specified

For TREGDMA-treated animals, exfoliation/desquamation was observed in all animals of the 25, 50 and 100% dose groups at some time during the study. Ulceration and excoriation also were seen in a few animals from these groups that resolved by day 35. No findings were recorded in the 5% dose group.

Hyperkeratosis was observed in all animals from the 25, 50, and 100% dose groups and acanthosis was observed in 80 or 100% of the animals from these groups. A single animal was diagnosed with dermatitis from the 100% group. Grading of these lesions generally correlated with dose. No microscopic changes of the skin were noted for the 5% dosage.

Skin basal cell proliferation (PCNA assay) was increased in the 25, 50, and 100% groups, but statistically significant only in the 100% group.

Conclusions:

The 13 week-NOAEL of TREGDMA in mice for local effects (acanthosis, hyperkeratosis) was 5% in acetone (approx. 100 mg/kg bw/d). The 13 week-NOAEL for systemic effects was 100% (approx. 2000 mg/kg bw/d).

Executive summary:

In a 13 weeks dermal toxicity study, TREGDMA (91% a.i.) was applied to the clipped interscapular region of the back of 10 maleC3H/HeNHsd mice/dose at dose levels of 0 (control), 5, 25, 50 and 100% TREGDMA in acetone, corresponding to approx. 100, 500, 1000 and 2000 mg/kg bw/d. The doses were applied in 50 µL/animal/day 5 days per week.

During the treatment phase of the study, no effects were observed except for skin lesions at the site of treatment. Exfoliation and desquamation was observed in all animals of the 25, 50 and 100% dose groups at some time during the study. Ulceration and excoriation also were seen in a few animals from these groups that resolved by day 35. No findings were recorded in the 5% dose group.

The only treatment-related finding at necropsy, other than for treated skin, was an increase in liver weight of approx. 7 and 10% compared with the control group in the 50 and 100% groups, respectively. There was no clinical or histopathological evidence of liver toxicity, thus the etiology and biological significance of the increased weight was uncertain.

Hyperkeratosis was observed in all animals from the 25, 50, and 100% dose groups and acanthosis was observed in 80 or 100% of the animals from these groups. A single animal of the 100% group was diagnosed with dermatitis. No microscopic changes of the skin were noted for the 5% dosage.

Skin basal cell proliferation (PCNA assay) was increased in the 25, 50, and 100% groups, but was statistically significant only in the 100% group.

In this study, the 13 week-NOAEL of TREGDMA for local effects (acanthosis, hyperkeratosis) was 5% (approx. 100 mg/kg bw/d). The 13 week-NOAEL for systemic effects was 100% (approx. 2000 mg/kg bw/d).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

100

Study duration:

subchronic

Species:

mouse

Quality of whole database:

The source is generally of good quality, however the amount of substance per area for local effects cannot be calculated as the application area is not properly defined ("interscapular region of the back").

Additional information

For TREGDMA, a reliable (RL=1), relevant and adequate study is available on repeated dose toxicity via the oral route, as well as a series of dermal studies ranging from 14 days exposure to chronic exposure (78 weeks) (all with RL=2). In addition, TREGDMA will rapidly be hydrolyzed by unspecific carboxylesterases in the liver into methacrylic acid, MAA, and Tryethylene glycol, TREG (for details, see chapter toxicokinetics and the category document, respectively). Therefore data from the metabolites, namely90 d OECD 408 repeated dose toxicity studies (RL1) with MAA (inhalation) and TREGDMA (oral feeding)can be used as supporting information for the evaluation of the repeated dose toxicity of TREGDMA with a high level of confidence, especially as the rather continuous dosing regime of these studies corresponds to both the general occupational exposure and the exposure to a metabolite.

 

Oral route

Triethylenegylcol dimethacrylate, TREGDMA

In a Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test according to OECD Guideline 422 (22 March 1996) TREGDMA was administered to 10 Hsd: Sprague Dawley SD rats/sex/dose orally by gavage at dose levels of 0 (control), 100, 300 and 1000 mg/kg bw/d. The treatment schedule included 2 weeks before pairing, during pairing, post coitum and post partum periods up to day 3 post partum. Animals were administered for approximately 5 and 8 weeks for males and females, respectively.

No mortality occurred in the study. No clinical signs of toxicological significance were reported. Statistically significant reduction in body weight was noted in high dose males compared to controls from Day 15 of treatment to sacrifice; body weights of females were unaffected by treatment.

Food consumption was comparable between the control and treated groups.

No differences in motor activity, grip strength and sensory reactivity to stimuli were observed. The differences noted in land foot splay noted in low dose males and females were considered incidental since they were inconsistent between males (increase) and females (reduction) and without any dose correlation.

In haematology and urinanalysis no changes of toxicological significance were seen. The statistically significant decrease of reticulocytes recorded in females dosed with 1000 mg/kg bw/d was considered of no toxicological relevance since no associated alterations of the erythrocytes were observed. No changes in prothrombine time were noted. Bile acids showed a dose-related increase in almost all treated females. No other changes of toxicological significance were observed. Two males of the high dose group showed an increase of urea (mean value 35% above controls). However, due to the low incidence, this finding cannot be conclusively attributed to treatment.

Other statistically significant fluctuations of some biochemical parameters were recorded in treated animals, such as: chloride, calcium, sodium and potassium. Changes were of minimal magnitude, not consistent between sexes and/or not dose-related, therefore considered incidental.

All females mated with the exception of on female of the low dose group. Two females, 1 in the low dose group and 1 in the mid-dose group showed an irregular cycle (oestrus was never observed); the low dose female did not mate, the mid-dose female was found sperm positive after 8 days of paring but not pregnant at necropsy. These isolated cases were considered incidental. In the control group a total of 5 females were found not pregnant and 1 female had unilateral implantation with total resorption. In addition, 1 female in the low dose group, 2 females in the mid-dose group and 2 females in the high dose group were not pregnant.

Measurements of copulatory index, fertility index Pre-coital interval and the number of copulation plugs did not show differences between treated and control groups. No significant differences were observed in the number of implantation, corpora lutea, total litter size, pre-implantation loss, pre-birth loss and gestation length between control and treated groups.

Litter data and sex ratios were unaffected by treatment. Clinical signs of pups were comparable between groups. Decedent pups were found in all groups without dose relationship. Necropsy findings in decedent pups and in pups sacrificed on Day 4 post partum did not reveal any treatment-related effect.

A slight reduction in terminal body weight was noted in the mid- and high dose males (statistically significant in high dose). Terminal body weight of females was unaffected by treatment. A slight increase in absolute and relative liver weight was observed in high dose females compared to controls. No relevant changes were detected at post mortem examination in treated animals, when compared with controls.

No treatment-related changes were seen in selected organs/tissues evaluated in males or females nor in the abnormalities detected in all groups at post mortem including the staging in the spermatogenic cycle.

Although changes in body weight gain of high dose males, bile acids and liver weight of high dose females were observed and since the microscopic examination revealed no lesion in any organs, the dosage of 1000 mg/kg bw/d is considered the NOAEL for this study.

 

Triethylene glycol, TREG (alcohol metabolite)

In the subchronic study (90 d, rats) with TREG at concentrations of 0, 748, 1522, 3849 mg TEG/kg/day (= 0, 10000, 20000 or 50000 ppm) for males and 0, 848, 1699, 4360 mg TEG/kg/day (= 0, 10000, 20000, 50000 ppm) for females, there was neither mortality nor signs of toxicity. and no dosage-related effects with serum chemistry, gross and microscopic pathology. Body weights were reduced during the dosing period with both males and females of the high dosage. Body weight gains were reduced at all dosages with males and females. No hematological effects were seen with females, but males of the mid- and high-dosage groups had slight reduced erythrocyte count and hematocrit, and high-dose males had decreased hemoglobin concentration with increased mean corpuscular volume. These were considered to reflect a mild hemodilution related to the absorption of large TEG doses. Urinalysis showed dosage-related decreased pH. and increased urine volume mainly at the high dose. These were probably related to the renal excretion of absorbed TEG and/or metabolites. Kidney weight was increased for high-dose females , and increased relative (to body) weight of kidneys for males and females from the mid- and high-dose groups were observed probably related to the renal excretion of the absorbed TEG and/or its metabolites. These findings indicate that the subchronic continuous per oral dosing of TEG to rats does not result in local or systemic specific organ or tissue toxicity. These findings contrast with the known repeated per oral toxicity. notably nephrotoxicity. produced by ethylene and diethylene glycols. Thus TEG has significantly lesser potential for systemic toxicity by the per oral route than its lower molecular weight homologues.

 NOAELs of 1522 mg/kg in males and 1699 mg/kg in females were observed.

 

Inhalative route

Methacrylic acid, MAA (methacrylic metabolite)

In an OECD 413, 90-day vapour inhalation study in Sprague Dawley rats with MAA revealed general toxicity at 350 ppm (1253 mg/m3) in male animals. Local, marginal irritation of the respiratory epithelium in the nasal cavity was observed in two female animals. No changes in sexual organs or sperm mobility and sperm head counts were noted. The NOAEL was 100 ppm (358 mg/m3) for local irritation effects in male and females The NOAEL for systemic effects based upon reduced body weight gain in the presence of reduced feed intake but no other systemic effects was also 100 ppm (358 mg/m3) in male and females.

 

Dermal route

TREGDMA

In a dose-range-finding study for a repeated-dose dermal toxicity study, TREGDMA (91% a.i.) was applied to the shaved skin of 5 male C3H/HeNHsd mice/dose at dose levels of 0, 25, 50 and 100% (applied in 50 µL), corresponding to approx. 500, 1000 and 2000 mg/kg bw/d for 14 days.

No mortality, no significant clinical signs, and no necropsy findings on internal organs were observed in all dose groups.

Desquamation and exfoliation was the only skin finding noted during the study and at necropsy in the 50 and 100% TREGDMA treated groups. Microscopic changes in the treated skin primarily consisted of dermatitis, intracorneal pustule formation, acanthosis, and hyperkeratosis. Epidermal necrosis or ulceration was not evident in the treated mice. 

The LOAEL for local effects (dermatitis, intracorneal pustules, acanthosis, hyperkeratosis) was 25% (approx. 500 mg/kg bw/d), a NOAEL for local effects could not be established. The 14 d-NOAEL for systemic effects was 100% (approx. 2000 mg/kg bw/d).

 

In a 14 day dermal toxicity study investigating cell proliferation in the skin, TREGDMA (91% a.i.) was applied daily to the clipped interscapular region of the back of 10 male C3H/HeNHsd mice/dose at dose levels of 0 (control), 5, 25, 50 and 100% TREGDMA in acetone, corresponding to approx. 100, 500, 1000 and 2000 mg/kg bw/d. The doses were applied in 50 µL/animal/day.

The mean body weight was decreased by approx. 10% in the 100% group. Other than gross and microscopic lesions of the treated skin, there were no effects from TREGDMA at doses up to 100%. Acanthosis was observed in all treated animals. Dermatitis and hyperkeratosis were observed in all animals from the 25, 50, and 100% groups. Statistically increased cell proliferation was observed for all doses.

The 14 day-LOAEL of TREGDMA in mice for local effects (acanthosis) was 5% in acetone (approx. 100 mg/kg bw/d). No NOAEL for local effects was established in this study.

 

In a 13 weeks dermal toxicity study, TREGDMA (91% a.i.) was applied to the clipped interscapular region of the back of 10 maleC3H/HeNHsd mice/dose at dose levels of 0 (control), 5, 25, 50 and 100% TREGDMA in acetone, corresponding to approx. 100, 500, 1000 and 2000 mg/kg bw/d. The doses were applied in 50 µL/animal/day 5 days per week.

During the treatment phase of the study, no effects were observed except for skin lesions at the site of treatment. Exfoliation and desquamation was observed in all animals of the 25, 50 and 100% dose groups at some time during the study. Ulceration and excoriation also were seen in a few animals from these groups that resolved by day 35. No findings were recorded in the 5% dose group.

The only treatment-related finding at necropsy, other than for treated skin, was an increase in liver weight of approx. 7 and 10% compared with the control group in the 50 and 100% groups, respectively. There was no clinical or histopathological evidence of liver toxicity, thus the etiology and biological significance of the increased weight was uncertain.

Hyperkeratosis was observed in all animals from the 25, 50, and 100% dose groups and acanthosis was observed in 80 or 100% of the animals from these groups. A single anima of the 100% group was diagnosed with dermatitis. No microscopic changes of the skin were noted for the 5% dosage. Skin basal cell proliferation (PCNA assay) was increased in the 25, 50, and 100% groups, but was statistically significant only in the 100% group. In this study, the 13 week-NOAEL of TREGDMA for local effects (acanthosis, hyperkeratosis) was 5% (approx. 100 mg/kg bw/d). The 13 week-NOAEL for systemic effects was 100% (approx.2000 mg/kg bw/d).

 

In a 78 weeks dermal carcinogenicity study, TREGDMA (91% a.i.) was applied to the clipped interscapular region of the back of 70 male C3H/HeNHsd mice/dose at dose levels of 5, 25 and 50% TREGDMA in acetone, corresponding to approx. 100, 500 and 1000 mg/kg bw/d. Untreated and acetone-treated control groups were used as controls.The doses were applied in 50 µL/animal/day 5 days per week.

Cutaneous treatment of male mice with TREGDMA did not result in any treatment-related changes in hematology, clinical chemistry, body weights or weight gain. There was a significant increase in mortality in the 50% TREGDMA dose group compared to the control groups. However, there were no clinical or histological effects to which the increased mortality could be attributed, and it was uncertain whether test substance related toxicity was directly responsible.

A dose-related increase in kidney weight was observed in the 25 and 50% dose groups at the terminal sacrifice. However, there were no correlating microscopic findings in the kidneys and the biological significance of the increase in weight was uncertain. Clinical signs of irritation, consisting primarily of exfoliation were observed in all dose groups. The time of onset, incidence, and severity of exfoliation were related to dose.

The mean measured rate of epidermal basal cell proliferation of the mid and high dose groups was consistently increased compared to both control groups at each measurement. There was no relationship between chronic inflammation of the skin and cell proliferation and the induction of skin tumors in normal mouse skin after 78 weeks of treatment although there was evidence of irritation and cell proliferation throughout the treatment period. There was no indication of carcinogenicity at any dose level.

The NOAEL for local effects was 5% (approx. 100 mg/kg bw/d). Taking into account the increased mortality and effects in the kidneys in the high dose group the systemic NOAEL is 25% (approx.500 mg/kg bw/d).

 

 

Summary

In a Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test (OECD 422) with triethyleneglycol dimethacrylate no relevant toxic effects were seen in parental animals up to the highest dose group of 1000 mg/kg bw/d. On the basis of the results obtained in the study, the NOAEL for both, general toxicity and reproduction/developmental toxicity was 1000 mg/kg bw/d (males/females).

The absence of adverse effects in the high dose group indicates only little likelihood that adverse effects at the same dose levels or effects at lower doses would occur in studies of longer duration (e.g. 90 day study).

This assumption is confirmed by a 90 day oral toxicity study of the alcohol TREG which is a metabolite in the first step after ester hydrolysis. In this study slight effects regarding body weight gain (males, females) and slight hematological effects (males) and increased kidney weights in mid and high dose group probably related to absorbed TREG and/or its metabolites were observed. NOAELs of 1522 mg/kg/d (males) and 1699 mg/kg/d (females) were determined for the alcohol TREG.

 

Following up to 78 weeks of cutaneous exposure to TREGDMA, only signs of local irritation at the site of application were observed in mice. No systemic toxicity has been observed.

 

The more recent OECD guideline 422 study was selected for risk assessment as the most relevant and adequate study due to more detailed documentation. From the dermal studies it can nevertheless be concluded that no systemic toxicity is to be expected for TREGDMA when administered via the dermal route even over longer duration.

 

Compliance to REACh requirements

The requirements are covered with an OECD 422 oral study in rats, a 90 d oral study in rats with the alcohol moiety Triethylene glycol and a 90 d inhalation study in rats with the methacrylic acid moiety MAA.

Justification for classification or non-classification

Based on the available data, TREGDMA does not need to be classified for repeated dose toxicity according to the criteria given in regulation (EC) 1272/2008 and UN-GHS. Thus, no labelling is required.