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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
publication
Title:
Relative Developmental Toxicities of Acrylates in Rats following Inhalation Exposure.
Author:
Saillenfait AM et al.
Year:
1999
Bibliographic source:
Toxicol. Sciences 48: 240-254

Materials and methods

Principles of method if other than guideline:
Groups of 20-29 bred female rats (17-25 pregnant) were exposed to the compound 6h/day on days 6 through 20 of gestation by inhalation. Control animals were exposed concurrently to filtered room air. The test concentrations of 2-hydroxyethyl acrylate were 1, 5, and 10 ppm (corresponding to approx. 4.8, 24.1, and 48.2 µg/L).
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
- Name of test material (as cited in study report): 2-Hydroxyethyl acrylate
- Analytical purity: 95.8 % (GC)
- Source: Roehm, Germany

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: IFFA CREDO Breeding Laboratories (Saint-Germain-sur-l' Arbresle, France)
- Age at study initiation: Young, nulliparous females
- Weight at study initiation: 200-220 g
- Housing: Single in clear polycarbonate cages with stainless-steel wire lids and hardwood shaving as bedding.
- Diet: Food pellets (UAR Alimentation Villemoisson, France), ad libitum
- Water: Filtered tap water, ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2
- Humidity (%): 50 ± 5
- Photoperiod (hrs dark / hrs light): 12 /12

Administration / exposure

Route of administration:
inhalation: vapour
Type of inhalation exposure (if applicable):
whole body
Vehicle:
air
Details on exposure:
EXPOSURE
Exposures were conducted in 200-L glass/stainless-steel inhalation chambers with dynamic and adjustable laminar air flow (6-20 m3/h). The chamber temperature was set at 23 ± 2°C, and the relative humidity at 50 ± 5 %. The exposure system delivered, with an infusion pump, a constant rate of liquid chemical from the top of a heated glass column filled with glass beads. Compressed air heated by a glass heater was introduced at the bottom of the glass column in a countercurrent fashion to the liquid flow. The vapourized compound was introduced into the main air inlet pipe of the exposure chambers.
Concentrations of acrylate ester were monitored continuously with a gas-chromatograph equipped with a flame ionization detector and an automatic gas-sampling valve. In addition, exposure levels were determined once during each 6-h exposure period by collecting atmosphere samples through glass tubes packed with activated charcoal. The charcoal samples were then desorbed with dichloromethane. The resulting samples were analyzed by gas chromatography using appropriate internal standards. Since 2-HEA has a rather low vapour pressure (0.07 mm Hg at 20 °C), the presence of liquid particles was evaluated at the highest concentration generated (i.e. 25 ppm). Airborn particles were measured with an Aerodynamic Particle Sizer.
No differences in particle counts were observed between the clean filtered air (control) and the vapour-laden air in the exposure chambers.

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Glass/stainless-steel inhalation chambers
- Source and rate of air: Test atmospheres were generated through an additional air-flow  rate passed through the fritted disk of a heated bubbler containing 2-hydroxyethyl acrylate.  The vapourized compound was introduced into the main air inlet pipe of the exposure chamber.
- Air flow rate: 6-20 m3/h

TEST ATMOSPHERE
- Brief description of analytical method used: GC/FID
- Samples taken from breathing zone: yes
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Analytical concentrations (mean ± SD):
1.1 ± 0.1 ppm (nominal: 1 ppm)
5.0 ± 0.6 ppm (nominal: 5 ppm)
10.6 ± 1.4 ppm (nominal: 10 ppm)
Details on mating procedure:
- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1/2-3
- Length of cohabitation: Overnight
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy
Duration of treatment / exposure:
day 6-20 of gestation
Frequency of treatment:
6h /day
Duration of test:
until gestation day 21
Doses / concentrationsopen allclose all
Dose / conc.:
1 ppm (nominal)
Remarks:
corresponding to approx. 4.8 µg/L
Dose / conc.:
5 ppm (nominal)
Remarks:
corresponding to approx. 24.1 µg/L
Dose / conc.:
10 ppm (nominal)
Remarks:
corresponding to approx. 48.2 µg/L
No. of animals per sex per dose:
20
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale:
Exposure concentrations were based on preliminary studies in which severe maternal toxicity (i.e. weight loss during GD 6-13 and pronounced reduction in weight gain during GD 13-21) was observed at 25 ppm hydroxyethyl acrylate. Maternal mortality also occurred at 25 ppm hydroxyethyl acrylate.

Examinations

Maternal examinations:
BODY WEIGHT: Yes
- Time schedule for examinations: On gestation day (GD) 0, 6, 13 and 21.

FOOD CONSUMPTION: YES
Food consumption was measured for the intervals GD 6-13 and 13-21.

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 21
- Organs examined: The uteri were removed and weighed. The number of implantation sites, resorptions, and dead and live fetuses were recorded.
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
The number of implantation sites, resorptions, and dead and live fetuses were recorded. Uteri which had no visible implantation sites were stained with ammonium sulfide (10 %) to detect very early resorptions.

Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: No data
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
Fetal examinations:
Live fetuses were weighed, sexed, and examined for external anomalies including those of the oral cavity. Half of the live fetuses from each litter were preserved in Bouin's solution and examined for internal soft tissue changes. The other half were fixed in ethanol (70 %), eviscerated, and then processed for skeletal staining with alizarin red S for subsequent skeletal examination.

- 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
Statistics:
Data were presented as mean ± SD. The number of  implantation sites and live fetuses and the various body weights were analyzed by one-way analysis of variance (ANOVA), followed by Dunnett's test if differences were found. The percentages of non-live  implants and  resorptions and the proportions of fetuses with alterations in each litter were evaluated by using the Kruskal-Wallis test, followed by the Dixon-Massey test where appropriate. Rates of pregnancy, fetal sex ratio, and percentage of litters with malformations or external, visceral, or skeletal variations were analyzed by using Fisher's test. Where applicable, least-squares analysis was carried out. For all statistical tests, the level of significance was set a priori at alpha = 0.05.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Description (incidence):
No test dams died.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Maternal body weight gain during GD 6-13 and absolute weight gain were significantly reduced at 10 ppm.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
A slight but statistically significant decrease in maternal food consumption was seen at 10 ppm for the entire exposure period.
Food efficiency:
no effects observed
Water consumption and compound intake (if drinking water study):
not examined
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:
no effects observed
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not examined

Maternal developmental toxicity

Details on maternal toxic effects:
No test dams died. Maternal body weight gain during GD 6-13 and absolute weight gain were significantly reduced at 10 ppm. A slight but statistically significant decrease in maternal food consumption was seen at 10 ppm for the entire exposure period.

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEC
Remarks:
systemic toxicity
Effect level:
ca. 0.024 mg/L air (nominal)
Based on:
test mat.
Basis for effect level:
body weight and weight gain
food consumption and compound intake

Maternal abnormalities

Key result
Abnormalities:
no effects observed

Results (fetuses)

Details on embryotoxic / teratogenic effects:
There were no significant changes in the numbers of implantations and live fetuses, incidence of non-live implants and resorptions, or fetal body weights across groups. The only malformation observed was a unilateral microphthalmia at 1 ppm. There were no significant changes in the incidence of external, visceral, or skeletal variations.

Effect levels (fetuses)

Key result
Dose descriptor:
NOAEC
Effect level:
ca. 0.048 mg/L air (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: developmental toxicity

Fetal abnormalities

Key result
Abnormalities:
no effects observed

Overall developmental toxicity

Key result
Developmental effects observed:
no

Any other information on results incl. tables

Maternal body weights:

 

Concentration [ppm/6h/d]

Maternal body weight GD 6 [g]

Absolute weight gain [g]

0

262 ± 18

34 ± 15

1

261 ± 16

31 ± 6

5

264 ± 18

29 ± 14

10

263 ± 21

15 ± 14**

 

 

Reproductive parameters:

Conc. [ppm/6h/d]

No. of litters

No. of implantation sites/litter

% of non-live implants/litter

% of resorption sites/litter

No. of live fetuses/litter

Average fetal body weight/litter [g]

0

21

14.71 ± 2.53

10.93 ± 13.99

10.93 ± 13.99

13.05 ± 2.91

5.68 ± 0.32

1

19

15.00 ± 3.27

8.93 ± 22.70

8.93 ± 22.70

14.61 ± 2.79

5.71 ± 0.27

5

22

14.91 ± 2.62

7.63 ± 11.02

7.36 ± 10.21

13.82 ± 2.94

5.69 ± 0.32

10

21

15.33 ± 1.53

6.52 ± 6.73

6.52 ± 6.73

14.33 ± 1.80

5.54 ± 0.25

 

 

Concentration [ppm/6h/d]

0

1

5

10

Mean % of fetuses with:

 

 

 

 

- any malformations/litter

0

0.40 ± 1.68

0

0

- external variations/litter

0.37 ± 1.68

0.40 ± 1.68

0.28 ± 1.33

0.62 ± 1.97

- visceral variations/litter

3.26 ± 9.12

5.16 ± 9.33

12.21 ± 19.56

9.48 ± 19.22

- skeletal variations/litter

19.37 ± 22.58

18.77 ± 19.53

25.05 ± 25.55

14.76 ± 13.58

- any variations/litter

11.60 ± 12.10

12.49 ± 12.85

18.49 ± 15.00

13.02 ± 12.79

 

* ,** Significant differences from the control (0 ppm) value, p< 0.05, and p< 0.01, respectively.

 

Applicant's summary and conclusion