Ethyl acrylate

Developmental toxicity / teratogenicity

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:

other: Acceptable, well-documented publication, comparable to current guidelines

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:

Toxicological Sciences 48: 240-245

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 ethyl acrylate were 25, 50, 100 and 200 ppm (corresponding to approx. 0, 0.10, 0.21, 0.41 and 0.82 mg/L)*.
* Calculation of concentrations (mg/L) based on Derelanko MJ (2000). Toxicologist's Pocket Handbook, CRC Press, conversion table, p. 57

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Ethyl acrylate

EC Number:

205-438-8

EC Name:

Ethyl acrylate

Cas Number:

140-88-5

Molecular formula:

C5H8O2

IUPAC Name:

ethyl acrylate

Details on test material:

- Name of test material (as cited in study report): Ethyl acrylate
- Analytical purity: more than 99 %

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system 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: Singly 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:

unchanged (no vehicle)

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 air-flow rate passed through the fritted disk of a heated bubbler containing the test chemical. 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 carbon disulfide. The resulting samples were analyzed by gas chromatography using appropriate internal standards. Since EA has a rather low vapour pressure (0.14 mm Hg at 20 °C), the presence of liquid particles was evaluated at the highest concentration generated (i.e. 100 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 vapor-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 ethylhexyl acrylate.  The vaporized 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:

The analytical concentrations were 18-29, 40-57, 91-131 and 181-235 ppm for the 25, 50, 100 and 200 ppm groups, respectively, as measured by gas chromatography.

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:

6 hours/day

Frequency of treatment:

daily on days 6-20 of gestation

Duration of test:

gestation day 21

No. of animals per sex per dose:

20

Control animals:

yes, sham-exposed

Details on study design:

- Dose selection rationale: Selection of exposure levels was based, in part on preliminary experiments in which marked decreases in maternal weight gain were observed at 200 and 300 ppm. Results from previous prenatal inhalation toxicity studies were also considered (Murray et al., 1981; Merkle and Klimisch, 1983). The high concentrations for the definitive study (200 and 300 ppm, respectively) were chosen to maximize the embryolethal or teratogenic potential.

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 recorded on 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

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
No maternal deaths were observed during this study. Exposure to 200 ppm led to significant decreases in maternal body weight gain throughout exposure and in absolute weight gain compared to those of controls.

Effect levels (maternal animals)

1

Dose descriptor:

NOAEC

Effect level:

0.41 mg/L air (nominal)

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

LOAEC

Effect level:

0.82 mg/L air (nominal)

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
Fetal body weights: Fetal body weights were significantly reduced at 200  ppm (7-8 % lower than control). 
Implantations and resorptions: There were no significant difference in the numbers of implantation sites and live fetuses, in the incidence of non-live implants and resorptions, or in the fetal sex ratio. 
Fetal malformations: Single occurrences of visceral malformations were seen in control and in the 50 and 200 ppm-treated groups. The incidences of external, visceral and skeletal variations were scattered, with no indication of adverse effects in any of the exposed groups when compared  to controls. 

Effect levels (fetuses)

1

Dose descriptor:

NOAEC

Effect level:

0.82 mg/L air (nominal)

Basis for effect level:

other: teratogenicity

2

Dose descriptor:

NOAEC

Effect level:

0.41 mg/L air (nominal)

Basis for effect level:

other: fetotoxicity

3

Dose descriptor:

LOAEC

Effect level:

0.82 mg/L air (nominal)

Basis for effect level:

other: fetotoxicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Change in Maternal Body Weight during days 6-20 of gestation

 

Concentration (ppm/6 h/day)	No. of dams	Body weight (g) on GD6	Body weight gain (g) on GD			Absolute weight gain (g)*
			6-13	13-21	6-21
0	17	284	34	94	129	24
25	18	289	34	86	120	27
50	19	293	32	93	125	26
100	19	291	30	91	121	15
200	17	285	17**	70**	87**	17**

* (day 21 body weight) - (gravid uterus weight) - (Day 6 body weight)

** Significant difference from the control (0 ppm) value, p < 0.01.

Reproductive parameters

Concentration (ppm/6 h/day)	No. of litters	No. of live fetuses per litter	Fetal sex ration (M:F)	Average fetal body weight (g) per litter
				All	Males	Females
0	17	13.94	1.17	5.51	5.63	5.36
25	17	13.23	1.01	5.50	5.64	5.35
50	19	13.42	0.95	5.50	5.65	5.36
100	19	14.26	1.02	5.57	5.66	5.44
200	17	15.35	0.86	5.07*	5.18*	4.97*

* Significant difference from the control (0 ppm) value, p < 0.01.

Concentration [ppm/6h/d]	0	25	50	100	200
Mean % of fetuses with:
- any malformations/litter	0.39 ± 1.62	0	0.38 ± 1.64	0	0.39 ± 1.62
- external variations/litter	0	0	0	0	0.33 ± 1.62
- visceral variations/litter	6.83 ± 13.46	7.95 ± 15.11	10.34 ± 15.51	10.71 ± 22.95	1.31 ± 3.69
- skeletal variations/litter	16.45 ± 19.67	19.65 ± 23.27	17.77 ± 18.51	15.00 ± 14.94	21.50 ± 16.97
- any variations/litter	11.51 ± 12.45	14.00 ± 15.55	13.84 ± 12.14	12.86 ± 12.58	11.51 ± 8.48

Food consumption: No data on food consumption are available because of  technical failure.

Exposure to 200 ppm EA caused overt maternal toxicity. This was evidenced by a decrease in body weight changes and a decrease in absolute weight gain. There were no effects in maternal toxicity in animals exposed to 100 ppm EA; therefore, the NOAEC for maternal toxicity was 100 ppm. There was no increase in incidence of malformations or variations at any dose level; therefore, the NOAEC for teratogenicity was > 200 ppm for EA.