Butyl acrylate

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study conducted in compliance with GLP regulations.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1980

Report date:

1980

Reference 2

Reference Type:

publication

Title:

Butyl and Methyl Acrylate: 13-week oral toxicity studies in CDF Fischer 344 rats.

Author:

Gorzinski SJ et al.

Year:

1982

Bibliographic source:

Toxicologist. 2: 33

Reference 3

Reference Type:

review article or handbook

Title:

No information

Author:

Gorzinski SJ et al.

Year:

1993

Bibliographic source:

Toxicologist. 2: 33, cited in Health Effects Assessment of Basic Acrylates, Ed.: Tyler, Murphy, Hunt, CRC-Press

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Butyl acrylate

EC Number:

205-480-7

EC Name:

Butyl acrylate

Cas Number:

141-32-2

Molecular formula:

C7H12O2

IUPAC Name:

butyl prop-2-enoate

Test material form:

other: liquid

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, MA.
- Age at study initiation: 63-64 days
- Housing: singly in suspended wire-mesh bottomed stainless steel cages
- Diet (e.g. ad libitum): Purina Laboratory Chow
- Water: The test solutions were the only sources of water for the rats.
- Acclimation period: 3 weeks


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±2
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Stability studies of butyl acrylate in water indicated some loss of the test material over a 4-day period (McCollister, et al, 1980). To compensate for the loss, the drinking water solutions containing butyl acrylate were prepared fresh daily, and at concentrations higher than those selected for test levels, as shown below:
Target Conc (w/v) Conc Prepared (w/v)
0.015% 0.02%
0.09% 0.12%
0.15% 0.22%

The solutions were prepared by adding 0.81 ml, 4.85 ml, or 8.9 ml of butyl acrylate to 3600 ml of fresh tap water in a one-gallon amber glass bottle in which a teflon rod was placed to facilitate mixing. Each bottle was mixed by rotation for approximately 1.5 hours.
McCollister, S. B. et al. Report No. HET K 23114- (6). The Dow Chemical Company, 1980.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The approximate actual concentrations for target levels of 0.015, 0.09 or 0.15 % butyl acrylate were 0.0162, 0.0997 or 0.1229 %, respectively.

Duration of treatment / exposure:

96-97 days

Frequency of treatment:

In an attempt to maximize ingestion of the test material, access to the drinking water was restricted to the time period from 4 p.m. to 8 a.m.

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 0.015, 0.09, 0.15 % in drinking water (males: 0, 12, 73, 84 mg/kg bw/d and females: 0, 15, 91, 111 mg/kg bw/d).
Basis:
nominal in water

No. of animals per sex per dose:

15

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
Based on the results of preliminary toxicity studies (McCollister, et al, 1980), levels of 0.015, 0.09 and 0.15% were selected as target concentrations.
McCollister, S. B. et al. Report No. HET K 23114- (6). The Dow Chemical Company, 1980.

Examinations

Observations and examinations performed and frequency:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily


BODY WEIGHT: Yes
- Time schedule for examinations: weekly


FOOD CONSUMPTION:
- Food consumption were recorded weekly on all rats throughout the study.


WATER INTAKE (if drinking water study): Yes
- Time schedule for examinations: once weekly


HAEMATOLOGY: Yes
- Time schedule for collection of blood: Males were evaluated after 78 days, and females, after 79 days on test. Blood was obtained from the tail vein.
- How many animals: 10 males and 10 females
- Parameters checked: Packed cell volume (PCV), erythrocyte count (RBC), hemoglobin (Hgb), and total and differential leukocyte counts (WBC).


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: After 63 days on test and at the termination of the experiment.
- Animals fasted: Yes, overnight
- How many animals: 5 males and 5 females after 63 days on test and rest all animals at the termination of the experiment.
- Parameters checked: blood urea nitrogen (BUN), serum glutamic pyruvic transaminase (SGPT) and serum alkaline phosphatase (AP).


URINALYSIS: Yes
- Time schedule for collection of urine: Males were evaluated after 78 days, and females, after 79 days on test.
- Parameters checked: urine samples were analyzed for specific gravity and pH; and semiquantitative evaluations were made of glucose, protein, ketones, bilirubin, blood and urobilinogen.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes
After 96-97 days on test and following an overnight fast, male and female rats, respectively, were weighed, killed by decapitation and examined for gross pathologic alterations. Immediately after decapitation, the eyes were examined in situ by means of a glass slide technique and fluorescent light illumination. Any ocular abnormalities were recorded as part of the gross pathologic observations. Weights of the brain, heart, liver, kidneys and testes were recorded for each rat.

Statistics:

Data on food consumption, water consumption, body weights, hematology and clinical chemistry determinations, urinary specific gravity, and absolute (g) and relative (g/l00 g body weight) organ weights were evaluated by a one-way analysis of variance; differences between treated and control groups were examined using Dunnett's Test (Steel and Torrie, 1960). The level of significance for all cases was p<0.05. Body weight and food and water consumption values that were statistical outliers were identified using the sequential outlier test of Grubbs (1969).
Steel, and Torrie, McGraw-Hill Book Company, Inc., New York, New York, 1960. pp. 101-105 and 111-112.
Grubbs, F. E. Technometrics Vol. II, No. 1 (1969).

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Food efficiency:

not examined

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

effects observed, treatment-related

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY: No mortality and clinical signs were observed.


BODY WEIGHT AND WEIGHT GAIN: No treatment related significant effects were observed. Few cases of statistically significant differences between experimental and control means was not considered to be compound-related. The very slight decrease in average body weight gain of male rats receiving the highest concentration might be the result of ingestion of butyl acrylate in drinking water.


WATER INTAKE (if drinking water study): Statistically significant decreases in water intake occurred at a number of the weekly measurements. All levels were affected, and the magnitude of the decreases were generally dose related. The approximate doses received from the drinking water on a mg butyl acrylate/kg body weight/day basis were calculated for each week using the overall mean actual concentrations, overall mean water consumption values, and weekly midpoint body weights for each group. The average doses received from target concentrations of 0.015, 0.09 and 0.15% were 12, 73, and 84 mg/kg/day, respectively, for males, and 15, 91, and 111 mg/kg/day, respectively, for females.


FOOD CONSUMPTION: There were no differences betwen experimental and control groups.


HAEMATOLOGY: No treatment related effects were observed.


CLINICAL CHEMISTRY: Clinical chemistry determinations revealed no statistically significant differences between treated and control groups.


URINALYSIS: Results of urinalyses were similar for experimental and control rats.


ORGAN WEIGHTS: Few statistically significant differences occurred between treated and control groups of rats. These statistical deviations were mostly limited to increases in absolute and relative kidney weights. In the groups of males, the increases occurred at the 0.09 and 0.015% levels, but not at the highest concentration. The females showed statistically significant increases in absolute kidney weights at the 0.015 and 0.15% levels, and in relative kidney weights at all 3 levels. These statistically significant differences were not considered to be compound related due to non dose-dependent, no histo-pathological changes, and no effects during repeated dose gavage study with 150 mg/kg bw butyl acrylate for 96-97 days. The remaining statistically significant differences in mean organ weights were random and not considered to be associated with treatment.


GROSS PATHOLOGY: Findings were similar for control and experimental rats.


HISTOPATHOLOGY: NON-NEOPLASTIC: Findings were similar for control and experimental rats. Examination of the kidneys from experimental rats revealed no differences from controls to account for the increased weight of that organ.

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

84 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: high dose

2

Dose descriptor:

NOAEL

Effect level:

111 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: high dose

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

The results reported herein indicates that butyl acrylate produced no definitive evidence of toxicity when administered to rats at a target concentration (0.15%) approaching the maximum attainable in drinking water for 96-97 days. A trend toward a decrease in body weight gain of male rats was judged to be the result of ingestion of this high dose level. Water consumption was decreased at all three levels of treatment (0.015, 0.09 and 0.15%), probably as a result of the unpalatability of the test substance in the drinking water. Thus, the results of this study indicate that rats maintained for 96-97 days on drinking water containing maximal soluble quantities of butyl acrylate had only minimal indications of toxicity.