3,7-dimethyloct-1-en-3-yl acetate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2015-05-15 to 2015-05-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU method B.47 (Bovine corneal opacity and permeability test method for identifying ocular corrosives and severe irritants)

Version / remarks:

April, 1997

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

Version / remarks:

July, 2013

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3,7-dimethyloct-1-en-3-yl acetate

EC Number:

269-847-3

EC Name:

3,7-dimethyloct-1-en-3-yl acetate

Cas Number:

68345-17-5

Molecular formula:

C12H22O2

IUPAC Name:

3,7-dimethyloct-1-en-3-yl acetate

Test material form:

liquid

Test animals / tissue source

Species:

cattle

Strain:

not specified

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Source: Schlachthof Bensheim, 64625 Bensheim, Germany
- Number of animals: not specified
- Characteristics of donor animals: at least 9 month old donor cattle
- Storage, temperature and transport conditions of ocular tissue:
The isolated eyes were transported to the laboratory in HBSS at ambient temperature. The corneae were isolated on the same day after delivery of the eyes. The corneae were directly used in the BCOP test on the same day.
- Time interval prior to initiating testing:
For equilibration, the corneae in the holder were incubated in a vertical position for about one hour at 32 ± 1 °C in a water-bath. At the end of the incubation period, the basal opacity was determined (t0).
- Selection and preparation of corneas:
The cornea was carefully removed from the eye using scalpel and rounded scissors. A rim of about 2 mm of tissue (sclera) was left for stability and handling of the isolated cornea.
Each isolated cornea was mounted in a specially designed cornea holder according to the description given in OECD guideline 437, that consists of anterior and posterior compartments, which interface with the epithelial and endothelial sides of the cornea, respectively. The endothelial side of the cornea was positioned against the sealing ring (O-ring) of the posterior part of the holder. The cornea was gently flattened over the O-ring but stretching was avoided. The anterior part of the holder was positioned on top of the cornea and fixed in place with screws. Both compartments of the holder were filled with incubation medium. The posterior compartment was filled first to return the cornea to its natural convex position. Care was taken to assure no air bubbles were present within the compartments.

- Quality check of the isolated corneas: All eyes were carefully examined macroscopically for defects. Those presenting defects such as vascularization, pigmentation, opacity and scratches were discarded. The basal opacity of all corneae was recorded. Each corneae with a value of the basal opacity > 7 was discarded.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

0.75 mL on the surface of the corneae

Duration of treatment / exposure:

10 minutes

Duration of post- treatment incubation (in vitro):

2 hours after rinsing with saline

Number of animals or in vitro replicates:

3 (test item and controls)

Details on study design:

NUMBER OF REPLICATES: 3

NEGATIVE CONTROL USED: yes, see above

POSITIVE CONTROL USED: yes, see above

APPLICATION DOSE AND EXPOSURE TIME: see above

POST-INCUBATION PERIOD: yes, 2 hours after rinsing with saline and before opacity measurement, at 32 ± 1 °C in incubation medium

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: via opacitometer OP_KiT opacitometer (Electro Design, 63-Riom France), measured before treatment (t0) and after 10 min treatment with test item or controls and 3 hours of post exposure incubation (t130)
- Corneal permeability: passage of sodium fluorescein dye (1 mL of a 0.4% (w/v) sodium fluorescein solution) measured after a 90 minutes incubation in a water-bath at 32 ± 1 °C with the aid of spectrophotometry via Versamax® Molecular Devices at OD490

SCORING SYSTEM: In Vitro Irritancy Score (IVIS)
IVIS(negative control) = opacity value + (15 x OD490 value)
IVIS(positive control or test item) = (opacity value – opacity value mean negative control) + (15 x corrected OD490 value)

DECISION CRITERIA:
1. IVIS ≤ 3: No Category (according to GHS)
2. IVIS > 3; ≤ 55: No prediction can be made
3. IVIS > 55: Serious eye damage according to CLP/EPA/GHS (Cat 1)

The test will be acceptable if
• the positive control gives an IVIS that falls within two standard deviations of the current historical mean (updated every three months), and if
• the negative control responses result in opacity and permeability values that are less than the established upper limits for background opacity and permeability values for bovine corneae treated with the respective negative control

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Run / experiment:

1

Value:

3.85

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

not determinable

Remarks:

No prediction can be made; threshold for serious eye damage: IVIS ≥ 55

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: No

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: With the negative control (saline) neither an increase of opacity nor permeability of the corneae could be observed (mean IVIS = 1.06).
- Acceptance criteria met for positive control: The positive control (2-Ethoxyethanol) was tested undiluted and showed a clear increase in opacity and distinctive increased permeability of the corneae (mean IVIS = 56.25) corresponding to a classification as serious eye damaging (CLP/EPA/GHS (Cat 1))

Any other information on results incl. tables

Test Group	Opacity value = Difference (t130-t0) of Opacity	Permeability at 490 nm (OD490)	Mean IVIS	Proposed in vitro Irritancy Score
Negative Control	0;0;0 Mean: 0.00	0.073; 0.066; 0.072 Mean: 0.070	1.10; 0.99; 1.08 Mean: 1.06	Not categorized
Positive Control	58.0; 52.0; 26.0	0.672; 0.784; 0.729	68.08; 63.76; 36.93 Mean: 56.25	Category 1
Test Item	4.00; 4.00; 4.00	-0.009; -0.017; -0.004	3.86; 3.74; 3.94 Mean: 3.85	No prediction can be made

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Conclusions:

In conclusion, according to the current study and under the experimental conditions reported, Dimethyl Octenyl Acetate (DMOE-Ac) is not serious eye damaging (CLP/EPA/GHS (Cat 1) but a prediction for the damage hazard cannot be made (GHS).

Executive summary:

This in vitro study was performed to assess the corneal damage potential of Dimethyl Octenyl Acetate (DMOE-Ac) by means of the BCOP assay using fresh bovine corneae.
After a first opacity measurement of the fresh bovine corneae (t0), the neat test item, the positive, and the negative controls were applied to corneae fixed in an incubation chamber in horizontal position for 10 minutes at 32 ± 1 °C. The posterior chamber contained incubation medium. After the incubation phase the test item, the positive, and the negative controls were each rinsed from the corneae. Further, the corneae were incubated for another 120 minutes at 32 ± 1 °C in a vertical position, while the anterior chamber contain incubation medium as well. Afterwards, opacity was measured a second time (t130).
After the opacity measurements permeability of the corneae was determined by measuring spectrophotometrically the transfer of sodium fluorescein after incubation in a horizontal position for 90 minutes at 32 ± 1 °C.
With the negative control (0.9% (w/v) NaCl solution in deionised water) neither an increase of opacity nor permeability of the corneae could be observed.
The positive control (2-Ethoxyethanol) showed a clear increase in opacity and distinctive increased permeability of the corneae corresponding to a classification as serious eye damaging (CLP/EPA/GHS (Cat 1)).
Relative to the negative control, the test item Dimethyl Octenyl Acetate (DMOE-Ac) caused a slight increase of the corneal opacity but no relevant changes in permeability. The calculated mean in vitro irritancy score was 3.85. According to OECD 437 (see table in chapter 3.10.3) the test item is not classified as serious eye damaging (CLP/EPA/GHS (Cat 1) but the test item’s hazard for eye damaging cannot be predicted.