Registration Dossier

Toxicological information

Developmental toxicity / teratogenicity

Currently viewing:

Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
14 Feb 1979 - 13 Mar 1979
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1979
Report Date:
1979
Reference Type:
publication
Title:
n-Butyl Acrylate: Prenatal Inhalation Toxicity in the Rat.
Author:
Merkle J and Klimisch H-J
Year:
1983
Bibliographic source:
Fund. Appl. Toxicol. 3: 443-447

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: Guidelines for reproduction studies for safety evaluation of drugs for human use, FDA, Jan. 1966 and Guidance on reproduction studies from the Association of the British Pharmaceutical Industry, 1975.
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): n-Butyl acrylate
- Analytical purity: 99.91%
- Impurities: water-0.01%, acrylic acid-0.0036%, di-n-butyl ether-0.01%, isobutyl acrylate-0.03%, methyl butyl acrylate-0.04%, hydroquinone monomethyl ether-17 ppm.

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Iffa Credo, Lyon, France
- Body weight at study initiation:
The mean body weight ± SD in dose groups 0, 25, 135 and 250 ppm were 209±12, 214±14, 214±9 and 219±16, respectively.
- Age at study initiation: 9-11 week
- Diet (e.g. ad libitum): Herilan Mrh-Zucht, H. Eggermann KG, Rinteln.
- Water: ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±2
- Humidity (%): 55±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:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
By means of a continuous infusion apparatus (UNITA I, B. Braun, Melsungen, Federal Republic Germany) constant amounts of the liquid product were supplied to a heated (about 80°C) evaporator. The n-butyl acrylate vapors were diluted with dust-free, conditioned fresh air and passed through 200 L inhalation chambers (all-glass construction with steel frame) under dynamic airflow conditions at a flow rate of 20 changes of air per hour (4000 L/h; 200 L chamber). A mean temperature of 24.5°C and a mean relative humidity of 53% were measured during exposure.


TEST ATMOSPHERE
- Brief description of analytical method used: The n-butyl acrylate test atmosphere concentrations were monitored analytically by means of a total
hydrocarbon analyzer (R 5 of RATFISCH, Munich). The total hydrocarbon analyzer was calibrated using an infrared analyzer Miran I (WILKS) calibrated with standards of known concentrations of n-butyl acrylate.
- Samples taken from breathing zone: yes


Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
The analytical concentrations (Mean ± SD) of the dose groups 25, 135 and 250 ppm were 25 ± 1, 137 ± 4 and 251 ± 3 ppm, respectively.
Details on mating procedure:
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy
Duration of treatment / exposure:
days 6-15 of gestation
Frequency of treatment:
6 hours per day
Duration of test:
21 days
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 25, 135 and 250 ppm (corresponding to 0, 0.13, 0.71 and 1.31 mg/L) Calculation of concentrations (mg/L) based on Derelanko MJ (2000). Toxicologist's Pocket Handbook, CRC Press, conversion table, p. 57.
Basis:
nominal conc.
No. of animals per sex per dose:
30
Control animals:
yes, sham-exposed

Examinations

Maternal examinations:
DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily


BODY WEIGHT: Yes
- Time schedule for examinations: day on which sperm had been detected (day 0) and on the 6th, 16th and 20th days post coitum.



POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on the 20th day post coitum.



Ovaries and uterine content:
Examinations included:
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of resorptions: Yes
Fetal examinations:
The weights and the length of fetuses were determined. After fixation in Bouin's solution, 1/3 of the fetuses were examined for organ changes according to the method of Wilson and Warkany (1965), and after staining of the skeleton (Dawson, 1926) 2/3 of the fetuses were investigated for skeletal changes.
Wilson, J.G. and Warkany, J. (1965). Teratology: Principles and Techniques. The University of Chicago Press, Chicago and London.
Dawson, A.B. (1926). Stain Technol. 1:123.
Statistics:
A trend analysis based on the generalization of the t-test according to Williams (1971, 1972) was carried out for the variables of maternal body weight and body weight gain, fetal weight and length, and placental weight in each case. The U-test (Krauth, 1971; Stucky and Vollmar, 1976) was carried out for the parameters of implantations per pregnant animal, live and dead embryos as percent per pregnant animal, and anomalies, variations and retardations as percent of live fetuses per litter.
Williams, D.A. (1971). Biometrics 27:103-117.
Williams, D.A. (1972). Biometrics 28:519-531.
Krauth, J. (1971). Ann. Math. Statist. 42:1949-1956.
Stucky, W. and Vollmar, J. (1976). J. Statist. Comput. Simul. 5:73-81.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
25 ppm were tolerated without any impairment of body weight. The body weight gain was significantly reduced after inhalation of 135 and 250 ppm during the period of treatment. In the period after the end of treatment (gd 16 - 20) the steepness of the body weight curve obtained after 135 and 250 ppm was similar to that of the control group. During the exposure 135 ppm led to distinct discharge from the eyes and noses and to ruffled fur. After inhalation of 250 ppm these symptoms were even more pronounced. No mortality occurred.

Effect levels (maternal animals)

Dose descriptor:
NOAEC
Effect level:
ca. 0.13 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:
The necropsy of the animals did not reveal any gross-pathological changes of the internal organs which could be attributed to the test substance. The number of corpora lutea and the number of implantations did not show any differences between the individual groups. After inhalation of 135 and 250 ppm the percentage of live implanations per pregnant animal was dose-dependent reduced. In the 135 and 250 ppm groups, the percentage of dead resorptions were significantly increased. No adverse effect on the weight and length of the fetuses was observed. No treatment related malformations and no signs of organ changes or skeletal abnormalities were observed in the fetuses at any concentration.

Effect levels (fetuses)

open allclose all
Dose descriptor:
NOAEC
Effect level:
ca. 0.13 mg/L air (nominal)
Basis for effect level:
other: embryotoxicity
Dose descriptor:
NOAEC
Effect level:
ca. 1.31 mg/L air (nominal)
Basis for effect level:
other: teratogenicity

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Any other information on results incl. tables

Maternal body weight development (mean values ± standard deviation):

 

Concentration [ppm]

Maternal body weight GD 0 [g]

Maternal body weight GD 20 [g]

Maternal body weight gain GD 0-20 [g]

0

209.38 ± 11.83

354.01 ± 36.66

144.64 ± 33.08

25

213.96 ± 13.94

359.62 ± 36.81

145.66 ± 29.87

135

213.68 ± 9.30

335.54 ± 43.00

121.87 ± 37.62*

250

218.64 ± 16.19

318.11 ± 42.79**

99.47± 33.68**

*  p < 0.05

** p < 0.01

Reproductive parameters:

 

Conc.  (ppm)   

no. pregnant/  total animals 

live fetuses/ animal 

resorptions (%)

weight of fetuses (g)

0

22/30

11.5 ± 5.34     

11.6

3.85 ± 0.41

25

23/30

10.6 ± 4.94     

13.8

4.08 ± 0.39

135

18/30

8.8 ± 5.14        

23.6*

4.09 ± 0.23

250

19/30

8.4 ± 5.68        

31.6*

4.08 ± 0.47

*: p<0.05

Conc.  (ppm)

% fetuses per litter with anomalies

% litters with fetuses showing anomalies

% fetuses per litter with variations/ retardations

% litters with fetuses showing variations/ retardations

0

2.7

23.8

19.7

81.0

25

0.9

9.1

11.2

59.1

135

1.9

18.8

10.2

43.8

250

0

0

8.2

43.8

 

0 ppm

25 ppm

135 ppm

250 ppm

Skeletal findings

Anomalies:

- Cleft vertebral centra

7/170

2/162

4/105

0/107

Variations/retardations:

- incomplete ossification of skull bone

0/170

0/162

1/105

0/107

- aplasia of sternebrae

16/170

11/162

3/105

3/107

-incomplete ossification of sternebrae

30/170

18/162

14/105

9/107

- asymmetric sternebrae

4/170

1/162

0/105

0/107

-accessory rib, bilateral

2/170

3/162

0/105

0/107

-accessory rib, bilateral and rudimentary

1/170

0/162

0/105

0/107

-accessory rib, unilateral and rudimentary

1/170

0/162

0/105

0/107

-general incomplete ossification of bones

1/170

2/162

1/105

1/107

Organ findings

Variations/retardations:

-dilatation of pelvis, unilateral

2/82

0/81

1/54

0/53

Units given as number found/number examined

 

Applicant's summary and conclusion