3,7-dimethyloct-6-en-3-ol

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study performed according to OECD 437 and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

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)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3,7-dimethyloct-6-en-3-ol

EC Number:

242-359-8

EC Name:

3,7-dimethyloct-6-en-3-ol

Cas Number:

18479-51-1

Molecular formula:

C10H20O

IUPAC Name:

3,7-dimethyloct-6-en-3-ol

Test material form:

liquid

Test system

Vehicle:

unchanged (no vehicle)

Amount / concentration applied:

0.75 mL

Duration of treatment / exposure:

10 min

Duration of post- treatment incubation (in vitro):

2 hours

Number of animals or in vitro replicates:

3 replicates

Details on study design:

Freshly isolated bovine eyes of at least 9 month old donor cattle were collected from the abattoir. Excess tissue was removed from the excised eyes. The isolated eyes were transported to the laboratory in HBSS containing 1% (v/v) Penicillin/Streptomycin (100 units/mL penicillin and 100 µg/mL streptomycin). The corneae were isolated on the same day after delivery of the eyes and were directly used in the BCOP test. All eyes were carefully examined macroscopically for defects. Those presenting defects such as vascularization, pigmentation, opacity and scratches were discarded. 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, which 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. 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). The anterior compartment received the test item or negative or positive control at a volume of 0.75 mL on the surface of the corneae. The corneae were incubated in a horizontal position at 32 ± 1 °C in the water-bath. The incubation time lasted ten minutes. After the test item or control items, respectively, were rinsed off from the application side with saline, fresh cMEM was added into the anterior compartment. Then the corneae were incubated at 32 ± 1°C for further two hours in a vertical position, followed by a second opacity reading (t130). In the second step of the assay, permeability of the corneae was determined.
The basal opacity of all corneae was recorded. Each cornea with a value of the basal opacity > 7 was discarded. Sets of three corneae were used for treatment with the test item and the negative and positive controls.

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Value:

1.2

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

With the negative control (saline) neither an increase of opacity nor permeability of the corneae could be observed (mean IVIS = 0.62).
The positive control (2-Ethoxyethanol) was tested undiluted and showed clear opacity and distinctive permeability of the corneae (mean IVIS = 101.22) corresponding to a classification as serious eye damaging (CLP/EPA/GHS (Cat 1)).
All acceptance criteria were fulfilled

In vivo

Irritant / corrosive response data:

The test item Dihydrolinalool was tested undiluted. Relative to the negative control, the test item Dihydrolinalool did not cause an increase of the corneal opacity or permeability. The calculated mean IVIS was 1.20 (threshold for serious eye damage: IVIS ≥ 55). According to OECD 437, the test item is not categorized.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In conclusion, according to the current study and under the experimental conditions reported, Dihydrolinalool is not categorized (GHS).

Executive summary:

This in vitro study was performed to assess the corneal damage potential of Dihydrolinalool 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 contains 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 clear opacity and distinctive 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 Dihydrolinalool did not cause an increase of the corneal opacity or permeability. The calculated mean in vitro irritancy score was 1.20. According to OECD 437 the test item is not categorized (GHS).