Hexamethylene diisocyanate, oligomerisation product, blocked with 2-butanone oxime

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Reliable without restriction, GLP guideline study

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes (incl. QA statement)

Remarks:

2009

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

(E)-(butan-2-ylidene)amino N-(5-{3-[6-(3-{6-[({[(butan-2-yl)amino]oxy}(hydroxy)methyl)amino]hexyl}-5-{5-[({[(E)-(butan-2-ylidene)amino]oxy}carbonyl)amino]pentyl}-2,4,6-trioxo-1,3,5-triazinan-1-yl)hexyl]-5-{5-[({[(E)-(butan-2-ylidene)amino]oxy}carbonyl)amino]pentyl}-2,4,6-trioxo-1,3,5-triazinan-1-yl}pentyl)carbamate; (E)-(butan-2-ylidene)amino N-[5-(3-{6-[({[(E)-(butan-2-ylidene)amino]oxy}carbonyl)amino]hexyl}-5-{5-[({[(E)-(butan-2-ylidene)amino]oxy}carbonyl)amino]pentyl}-2,4,6-trioxo-1,3,5-triazinan-1-yl)pentyl]carbamate; (E)-(butan-2-ylidene)amino N-[6-(3-{6-[({[(E)-(butan-2-ylidene)amino]oxy}carbonyl)amino]hexyl}-2,4-dioxo-1,3-diazetidin-1-yl)hexyl]carbamate

EC Number:

617-779-3

Cas Number:

85940-94-9

Molecular formula:

Not applicable (UVCB substance)

IUPAC Name:

(E)-(butan-2-ylidene)amino N-(5-{3-[6-(3-{6-[({[(butan-2-yl)amino]oxy}(hydroxy)methyl)amino]hexyl}-5-{5-[({[(E)-(butan-2-ylidene)amino]oxy}carbonyl)amino]pentyl}-2,4,6-trioxo-1,3,5-triazinan-1-yl)hexyl]-5-{5-[({[(E)-(butan-2-ylidene)amino]oxy}carbonyl)amino]pentyl}-2,4,6-trioxo-1,3,5-triazinan-1-yl}pentyl)carbamate; (E)-(butan-2-ylidene)amino N-[5-(3-{6-[({[(E)-(butan-2-ylidene)amino]oxy}carbonyl)amino]hexyl}-5-{5-[({[(E)-(butan-2-ylidene)amino]oxy}carbonyl)amino]pentyl}-2,4,6-trioxo-1,3,5-triazinan-1-yl)pentyl]carbamate; (E)-(butan-2-ylidene)amino N-[6-(3-{6-[({[(E)-(butan-2-ylidene)amino]oxy}carbonyl)amino]hexyl}-2,4-dioxo-1,3-diazetidin-1-yl)hexyl]carbamate

Details on test material:

- Name of test material (as cited in study report): HDI Trimer MEKO Blocked 85940-94-9

- Physical state: Liquid colorless, clear
- Analytical purity: 77.3% in acetone

- Lot/batch No.: GCZ 3405-1
- Expiration date of the lot/batch: 14 Oct 2009

- Stability under test conditions: The stability under the storage condition over the exposure period was guaranteed byt he sponsor and was checked during the study by analytical examination of filter samples.
- Storage condition of test material: Room temperature

Test animals

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories
- Age at study initiation: 10-12 weeks
- Weight at study initiation: Based on the pregnant animals the body weight on GD 0 varied between 147.6 -191.8 g.
- Fasting period before study:
- Housing: single-houses from GD 0-20
- Diet (e.g. ad libitum): mouse/rat "GLP" diet
- Water: ad libitum
- Acclimation period: yes. The animals were paired by the breeder and supplied on GD0 (=detection of vaginal plug/sperm). The animals arrived on
the same day (GD 0) at the experimental laboratory. The following day was designated as “GD 1”.
After delivery, the animals were subjected immediately to the acclimatization period in which they were adapted to the surroundings.
To reduce the stress during the exposure period, the animals were gently adapted to the daily handling and to the restraining head-nose inhalation systems from GD 1-GD 5 before start of exposure (pre-flow period).

During exposure, no food and drinking water were supplied.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): in the range of 20-24°C
- Humidity (%): in the range of 30-70%
- Air changes (per hr): 15 times per hour
- Photoperiod (hrs dark / hrs light): The light cycle rythm was 12 hours light from 06.00 h to 18.00 h and 12 hours darkness from 18.00 h to 06.00 h

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure (if applicable):

nose/head only

Vehicle:

acetone

Details on exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION:
See Table 7.8.2 a
- Exposure apparatus:
- Method of holding animals in test chamber: The rats were restrained in glass exposure tubes. Their snouts projected into the inhalation chamber
and thus they inhaled the aerosol.
- Source and rate of air: Conditioned supply air : 4.5 +/- 0.2 m3/h
- Method of conditioning air: Conditioned supply air is activated charcoal filtered air conditioned to about 50% +/- 20% relative humidity and 22°C +/- 2°C.
- System of generating particulates/aerosols: The aerosol was generated with compressed air in a mixing stage mixed with conditioned dilution air
and passed via the cyclonic separator into the inhalation system
- Temperature, humidity, pressure in air chamber:
- Air flow rate: See Table 7.8.2 a
- Air change rate: See Table 7.8.2 a
- Method of particle size determination:
See Table 7.8.2b
The particle size analysis was carried out with a cascade impactor. The calculation of the particle size
distribution was carried out in the Experimental Toxicology and Ecology of BASF SE on the basis of mathematical methods for evaluating particle
measurements (DIN 66141: Darstellung von Korngrößenverteilungen and DIN 66161: Partikelgrößenanalyse, Beuth-Vertrieb GmbH, Berlin und Köln,
Germany).
- Treatment of exhaust air: no data

TEST ATMOSPHERE
- Brief description of analytical method used:
The concentrations of the inhalation atmospheres were analyzed by gravimetry. A preweighed filter was placed into the filtration equipment. By means of a vacuum compressed air pump a defined volume of the aerosol was drawn through the filter.
The solvent concentration was determined by high pressure liquid chromatography (HPLC).
- Samples taken from breathing zone: yes

VEHICLE (if applicable)

- Composition of vehicle: acetone

- Concentration of test material in vehicle: 77.3% in acetone

- Purity of vehicle: no data

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

See Table 7.8.2abis
Analytical determination of concentrations
- Gravimetrical measurements
Daily means of the test substance concentration were calculated based on three measured samples per concentration and exposure. The
concentrations in mg/m³ were calculated from the difference between the weight of the preweighed filter and the weight of the filter after sampling, with reference to the sample volume of the inhalation atmosphere.
- HPLC measurements
Vapor concentrations of the solvent were determined once per exposure day in the control group and once every 4 days of exposure in test groups 1-3.

Details on mating procedure:

- Impregnation procedure: The animals were paired by the breeder and supplied on GD 0 (= detection of vaginal plug/sperm). After delivery, the
animals were subjected immediately to the acclimatization period in which they were adapted to the surroundings.

- M/F ratio per cage: The rats were single-housed from GD 0-20

- Length of cohabitation: No data


- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy
- Any other deviations from standard protocol:

Duration of treatment / exposure:

From Gestational Day (GD) GD6 to GD19.

Frequency of treatment:

6 hours per day

Duration of test:

From mating procedure foolowing by detection of vaginal plug (GD0) to GD 19. Day 20 necropsy of the dams

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/m³ air (nominal)

Doses / concentrations 2

Dose / conc.:

5 mg/m³ air (nominal)

Doses / concentrations 3

Dose / conc.:

25 mg/m³ air (nominal)

Doses / concentrations 4

Dose / conc.:

150 mg/m³ air (nominal)

No. of animals per sex per dose:

See Table 7.8.2c
25 female rats per dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The doses have been selected considering the 90-day inhalation repeated exposure (OECD 413).

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: A check was made twice a day on working days or once a day on Saturdays, Sundays or on public holidays (GD 0-20).


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: During pre-flow period and on the day of necropsy the animals were examined for clinical symptoms at least once a day. During the exposure period, a clinical inspection of each animal was performed at least three times a day (before, during and after exposure). During the exposure procedure a groupwise examination was conducted.

BODY WEIGHT: Yes
- Time schedule for examinations: All animals were weighed on GD 0, 1, 3, 6, 8, 10, 13, 15, 17, 19 and 20. The body weight change of the animals was
calculated based on the obtained results.

FOOD CONSUMPTION : Yes
With the exception of GD 0, the consumption of food was determined on the same days as body weight.


WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on GD 20
- Organs examined: Head, larynx, trachea, lungs and mediastinal lymph nodes
See Table 7.8.2d

OTHER:
Corrected (net) body weight gain: The corrected body weight gain was calculated after terminal sacrifice (terminal body weight on GD 20 minus weight of the unopened uterus minus body weight on GD 6).

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: Yes: [all per litter / half per litter / #? per litter ] / No / No data

Statistics:

See Table 7.8.2 d and e

Historical control data:

yes

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food efficiency:

not specified

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

The lung of one female animal (No. 98) of test group 3 (150 mg/m³) showed foci. This finding was regarded to be treatment-related.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

In the lungs of seven animals of test group 3 (150 mg/m³) multiple granuloma were observed.
These granuloma were focal agglomerations of mainly histiocytes and fewer neutrophils adjacent to or including the alveolar wall. In addition, in these animals histiocytes and fewer lymphocytes were observed peribronchiolar surrounding small bronchi. The particular animal with the macroscopic finding (foci) in the lung (No. 98) showed the most severe (grade 3) histopathologic effect.

Histopathological findings: neoplastic:

not specified

Maternal developmental toxicity

Number of abortions:

not specified

Pre- and post-implantation loss:

not specified

Description (incidence and severity):

One control (No. 16), one low dose (No. 35) and two mid dose (Nos. 67 and 68) dams were
pregnant by stain and had only very early resorptions (1-3) in the uterus. If this occurs in
isolation, it is not an unusual spontaneous finding in the strain of rats used for this study.

Description (incidence and severity):

One control (No. 16), one low dose (No. 35) and two mid dose (Nos. 67 and 68) dams were
pregnant by stain and had only very early resorptions (1-3) in the uterus. If this occurs in
isolation, it is not an unusual spontaneous finding in the strain of rats used for this study.

Dead fetuses:

not specified

Changes in pregnancy duration:

not specified

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not specified

Changes in number of pregnant:

no effects observed

Details on maternal toxic effects:

Maternal toxic effects:yes. Remark: lungs

Details on maternal toxic effects:
See Table 7.8.2f
The lung of one female animal (No. 98) of test group 3 (150 mg/m³) showed foci.This finding was regarded to be treatment-related.
Histopathology has been performed in all animals of the 3 groups.
In the lungs of seven animals of test group 3 (150 mg/m³) multiple granuloma were observed. These granuloma were focal agglomerations of mainly histiocytes and fewer neutrophils adjacent to or including the alveolar wall. In addition, in these animals histiocytes and fewer lymphocytes were
observed peribronchiolar surrounding small bronchi. The female animal (N°98) with the macroscopic finding (foci) in the lung (No. 98) showed the most severe (grade 3) histopathologic effect.

Effect levels (maternal animals)

1

Dose descriptor:

NOAEC

Effect level:

>= 25 - < 150 mg/m³ air (nominal)

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOEC

Effect level:

>= 150 mg/m³ air (nominal)

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Fetal body weight changes:

no effects observed

Changes in sex ratio:

no effects observed

External malformations:

effects observed, non-treatment-related

Description (incidence and severity):

One fetus in test group 2 (25 mg/m³) had multiple external malformations and for another fetus from a different litter in this test group a gastroschisis was noted.
Because a dose-response relationship was missing these findings were considered to be spontaneous in nature.

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

One fetus with multiple skeletal malformations was noted in test group 2 (25 mg/m³;) Neither statistically significant differences between the test groups nor a doseresponse relationship were observed and the incidence of skeletal malformations was comparable to the historical control data. Thus an association of one malformed fetus to the treatment is not assumed.

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
No embryotoxic / teratogenic effects

Effect levels (fetuses)

Remarks on result:

not determinable due to adverse toxic effects at highest dose / concentration tested

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Table 7.8.2f Overview of the relevant histopathological findings

Lungs	Female animals
Test group (mg/m³)	0	1 (5)	2 (25)	3 (150)
Organs examined	25	25	25	25
Granuloma, multiple	0	0	0	7
·        Grade 1				4
·        Grade 2				2
·        Grade 3				1

RESULTS

EXAMINATION OF THE DAMS

Clinical examination

In this study, according to the requirements of the corresponding test guidelines, each test group including the controls contained a sufficient number of females with implantation sites at necropsy (respectively 21, 22 and 23 for Test group 1, 2 and 3).

Mortality: There were no test substance related or spontaneous mortalities in any group.

Clinical symptoms: No test substance related clinical symptoms signs or any disturbances of the general behavior were observed in any dam during the entire study period.

Food consumption: The average food consumption was comparable to the control group in all test groups and did not show a test substance-related impairment.

Body weight data: The average body weights and body weight gain were comparable among control and treated group during the entire study.

Corrected (net) body weight gain: The corrected body weight gain (terminal body weight on GD20 minus weight of the unopened uterus minus body weight on GD6) did not show any difference of biological relevance between the test substance-treated groups and the control group.

Terminal examination of the dams

Uterus weight: The mean gravid uterus weight of the animals of all test groups were not influenced by the test substance.

Reproduction data of dams: The conception rate reached, 84%, 88% and 92% respectively for test group 1, 2 and 3. There were no test substance-related and or biologically relevant differences between the different test groups in conception rate, the mean number of corporea lutea and implantation sites, the number of resorptions and viable fetuses or in the values calculated for the pre- and the post-implantation losses.

EXAMINATION OF THE FETUSES

Sex distribution of fetuses : The sex distribution of the fetuses in the treated groups was comparable to the control fetuses.

Weight of placenta: The mean placental weights in the treated groups were comparable to the controls.

Weight of fetuses: The mean fetal weights of all treated groups were not influenced by the test substance.

External examination of the fetuses

Fetal external malformations

One foetus in test group 2 had multiple external malformations and for another fetus from a different litter in this group a gastroschisis was noted. Because a dose-response relationship was missing these findings were considered to be spontaneous in nature.

Fetal external variations

No external variations was recorded in this study.

Fetal external unclassified observations

One unclassified external observation, i.e. fused placentae, was recorded for one littermate of the high dose group and was assessed as spontaneous in nature.

Soft tissue examination of the fetuses

Fetal soft tissue malformations

One sole soft tissue malformation was recorded (anophtalmia) was recorded in one fetus from one litter in the high dose group. This was an isolated finding which may occur spontaneously in Wistar rats . Thus an association of this finding to treatment is not assumed.

Fetal soft tissue variations

Two soft tissues variations (uni or bilateral dilation of renal pelvis and ureter) were detected in 3 to 4 fetuses of 3 to 4 litters in each test group including the controls and showed no dose-response relationship. The observable differences between the groups reflect the usual fluctuation for this parameter and were clearly within the range of the historitical control data.

Fetal soft tissue unclassified observations

No unclassified soft tissue observations were recorded.

Skeletal examination of the fetuses

Fetal skeletal malformations

One fetus with multiple skeletal malformations was noted in test group 2. Neither statistically significant differences between the test groups nor a dose-response relationship were observed and the incidence of skeletal malformations was comparable to the historitical data. Thus an association of one malformed fetus to the treatment is not assumed.

Fetal skeletal variations

For all groups, skeletal variations of different bone structures were observed, with or without effects on corresponding cartilages. The total incidence of skeletal variations showed no relation to dosing and was comparable to the historical control data.

two specific skeletal variations, misshapen sternebra with unchanged cartilage and supernumerary 14th rib without cartilage, was statistically significantly increased in several test groups compared to the concurrent control.

Both findings are quite common in gestation day 20 rat fetuses of this strain, as can be seen from the historical control data. An increased incidence of supernumerary 14th rib was not dose-dependently present in the low- and mid-dose groups ans was well within the historical range. An increased incidence of misshapen sternebra with unchanged cartilage was not dose-dependently present in the mid- and high-dose groups and was rather marginally outside the historical control range. Neither an association of these findings to treatment nor a specific adversity is assumed for these minor changes of the ossification process.

Fetal skeletal unclassified cartilage observations

Some isolated findings without impact on the respective bone structures, which mere designed as unclassified cartilage observations, occured in all groups including the control. The observed unclassified cartilage findings did not show a relation dosing and were considered to be spontaneous in nature.

Table 7.8.2 f Individual fetal external malformations

Test group	Dam No.-Fetus No., Sex	Malformations
0 (control)	none
1 (5 mg/m³)	none
2 (25 mg/m³)	57-01, M^a)	Fetus with multiple external observations
	62-03, M	Gastroschisis
3 (150 mg/m³)	none

Table 7.8.2 g Total external malformations

		Test group 0 0 mg/m³	Test group 1 5 mg/m³	Test group 2 25 mg/m³	Test group 3 150 mg/m³
Litter Fetuses	N N	24 225	20 172	20 182	23 233
Fetal incidence	N	0 (0.0%)	0 (0.0%)	2 (1.1%)	0 (0.0%)
Litter incidence	N	0 (0.0%)	0 (0.0%)	2 (10%)	0 (0.0%)
Affected fetuses/ litter	Mean%	0.0	0.0	2.2	0.0

Table 7.8.2h Individual fetal soft tissue malformations

		Test group 0 0 mg/m³	Test group 1 5 mg/m³	Test group 2 25 mg/m³	Test group 3 150 mg/m³
Litter Fetuses	N N	24 225	20 172	20 182	23 233
Fetal incidence	N	0 (0.0%)	0 (0.0%)	2 (1.1%)	0 (0.0%)
Litter incidence	N	0 (0.0%)	0 (0.0%)	2 (10%)	0 (0.0%)
Affected fetuses/ litter	Mean%	0.0	0.0	2.2	0.0

Table 7.8.2i Total fetal soft tissue malformations

		Test group 0 0 mg/m³	Test group 1 5 mg/m³	Test group 2 25 mg/m³	Test group 3 150 mg/m³
Litter Fetuses	N N	24 107	20 82	20 87	23 112
Fetal incidence	N	0 (0.0%)	0 (0.0%)	0 (0.0%)	1 (0.9%)
Litter incidence	N	0 (0.0%)	0 (0.0%)	0 (0.0%)	1 (4.3%)
Affected fetuses/ litter	Mean%	0.0	0.0	0.0	0.7

Table 7.8.2j Total soft tissue variations

		Test group 0 0 mg/m³	Test group 1 5 mg/m³	Test group 2 25 mg/m³	Test group 3 150 mg/m³
Litter Fetuses	N N	24 107	20 82	20 87	23 112
Fetal incidence	N	4 (3.7%)	4 (4.9%)	4 (4.6%)	3 (2.7%)
Litter incidence	N	4 (17%)	4 (20%)	4 (20%)	3 (13%)
Affected fetuses/litter	Mean%	3.6	5.6	4.6	2.7

Table 7.8.2k Individual fetal skeletal malformations

		Test group 0 0 mg/m³	Test group 1 5 mg/m³	Test group 2 25 mg/m³	Test group 3 150 mg/m³
Litter Fetuses	N N	24 107	20 82	20 87	23 112
Fetal incidence	N	4 (3.7%)	4 (4.9%)	4 (4.6%)	3 (2.7%)
Litter incidence	N	4 (17%)	4 (20%)	4 (20%)	3 (13%)
Affected fetuses/litter	Mean%	3.6	5.6	4.6	2.7

Table 7.8.2l Total skeletal malformations

		Test group 0 0 mg/m³	Test group 1 5 mg/m³	Test group 2 25 mg/m³	Test group 3 150 mg/m³
Litter Fetuses	N N	24 107	20 82	20 87	23 112
Fetal incidence	N	4 (3.7%)	4 (4.9%)	4 (4.6%)	3 (2.7%)
Litter incidence	N	4 (17%)	4 (20%)	4 (20%)	3 (13%)
Affected fetuses/litter	Mean%	3.6	5.6	4.6	2.7

Table 7.8.2m Total skeletal variations

		Test group 0 0 mg/m³	Test group 1 5 mg/m³	Test group 2 25 mg/m³	Test group 3 150 mg/m³
Litter Fetuses	N N	24 107	20 82	20 87	23 112
Fetal incidence	N	4 (3.7%)	4 (4.9%)	4 (4.6%)	3 (2.7%)
Litter incidence	N	4 (17%)	4 (20%)	4 (20%)	3 (13%)
Affected fetuses/litter	Mean%	3.6	5.6	4.6	2.7

Table 7.8.2m bis Occurrence of statistically significantly increased fetal skeletal variations (expressed as mean percentage of affected fetuses/litter)

Finding	Test group 0 0 mg/m³	Test group 1 5 mg/m³	Test group 2 25 mg/m³	Test group 3 150 mg/m³	HCD Mean % (range)
Misshapen sternebra; unchanged cartilage	56.0	57.3	76.5**	68.4*	49.9 (36.0-63.4)
Supernumerary 14^thrib; cartilage not present	43.3	71.4**	61.5*	45.5	59.6 (41.8-73.1)

Table 7.8.2n Total skeletal unclassified cartilage observations

		Test group 0 0 mg/m³	Test group 1 5 mg/m³	Test group 2 25 mg/m³	Test group 3 150 mg/m³
Litter Fetuses	N N	24 118	20 90	20 95	23 121
Affected fetuses/ litter	Mean%	53.9	43.9	47.7	49.1

Applicant's summary and conclusion

Conclusions:

In conclusion, the no observed adverse effect level (NOAEC) for maternal toxicity is 25 mg/m³ based on multiple granuloma in the lungs in the dams at 150 mg/m³.
The no observed adverse effect level (NOAEC) for prenatal developmental toxicity is 150 mg/m³. No adverse fetal findings of toxicological relevance were evident at any dose.

Executive summary:

In a Prenatal Developmental toxicity study performed according to the guideline OECD 414, in compliance with GLP, HDI Trimer MEKO-blocked (77.3% in acetone) was administered to 25 female Wistar rats per dose by inhalation at dose levels of 5, 25 and 150 mg/m3 from Day 6 to Day 19 of gestation (GD= Gestational Day). The control group, consisting of 25 females, was exposed to acetone in parallel. At terminal sacrifice on Day 20, 21 to 25 females per group had implantation sites.

The analyses of the atmospheres showed that the scheduled aerosol concentrations were met and the particule sizes of the aerosol in the inhalation atmosphere were within the respirable range.

There were no toxicologically relevant effects on the dams concerning mortality and clinical observations, food consumption, body weight and gross/net body weight gain up to 150 mg/m3. Overt signs of maternal toxicity in the lungs

were observed at the high dose of 150 mg/m3 confirmed by test susbtance-related histopathological findings.In the highest dose group, one animal showed foci in the lung at macroscopical examination and at microscopical examination this animal showed the most severe (grade 3) granuloma and seven animals revealed multiple granuloma in the lungs. These findings were regarded to be treatment-related and adverse. Animals of the intermediate and low dose (25 and 5 mg/m3) were not affected.

No test substance-related effects were detected in the dams concerning gestational parameters as well as uterine and placental weights up to 150 mg/m3. Terefore the NOAEC for maternal toxicity is 25 mg/m3 based on multiple granuloma in the lungs at 150 mg/m3.

Fetal examinations showed no changes in sex distribution and fetal body weight of the fetuses. HDI Trimer MEKO-blocked has no adverse effect on prenatal development of offspring at any of the dose levels tested. Therefore, the NOAEC for prenatal developmental toxicity is determined at 150 mg/m3 and above. No adverse fetal findings of toxicity were evident at any dose.

Therefore, HDI Trimer MEKO-blocked is not classified for prenatal developmental toxicity according to the criteria of the

Annex VI to the Directive 67/548/EEC and the Annex I to the CLP Regulation (EC) N°( 1272-2008).