6-methyl-3,4-dihydro-2H-1,4-benzoxazine

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12th August 2020 - 17th August 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Prior to undertaking in-vivo irritation testing the Study Director conducted a weight-of-evidence analysis, to ensure that the in-vivo testing was sufficiently justified. This study was conducted as both in-vitro studies were inconclusive. Eye (Bovine, OECD 437): no prediction; Eye (EpiOcular Test): borderline.

For classification purposes an in vivo study was conducted.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

6-methyl-3,4-dihydro-2H-1,4-benzoxazine

EC Number:

837-106-9

Cas Number:

71472-57-6

Molecular formula:

C9H11NO

IUPAC Name:

6-methyl-3,4-dihydro-2H-1,4-benzoxazine

Test material form:

liquid

Specific details on test material used for the study:

Chemical Name: 6-methyl-3,4-dihydro-2H-1,4-benzoxazine
CAS number: 71472-57-6
Intended use: Industrial chemical
Appearance: Light yellow liquid
Storage conditions: 2 to 8°C, protected from light. Kept in storage container under protective atmosphere.
Supplier: Sponsor
Batch number: AMRI-1394906005
Expiry date: 01 September 2020
Purity: >99%
Supplier’s responsibilities: Characterisation of the test item and the documentation of the methods of synthesis, fabrication or derivation and stability.

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Acclimatisation period: 36 to 37 weeks prior to the start of the study
- Age at start of treatment: Approx 43 to 50 weeks
- Weight at start of treatment: 2.76 to 4.60 kg
- Housing: Individually in a plastic cage with perforated floors
- Diet: 150g of a standard laboratory rabbit diet per day
- Water: Drinking water provided ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 15-21
- Humidity (%): Relative humidity of 45-70
- Photoperiod (hrs dark/hrs light): Lighting was controlled by means of a time switch to give 12 hours of artificial light in each 24 hour period.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0.1 mL

The eyes of each animal were examined prior to installation of the test item to ensure that there was no pre-existing corneal damage, iridial inflammation or conjunctival irritation.

The dose was instilled into the right eye by pulling the lower eyelid away from the eye ball to form a cup into which the test item was dropped. The eyelids were then held together for one second before releasing. The left eye remained untreated and unexposed for control purposes.

Duration of treatment / exposure:

72 hours

Observation period (in vivo):

The animals were returned to their cages and checked at least twice during the first hour after dosing and at regular intervals throughout the day to ensure no severe injury passed unnoticed. Ocular reactions to treatment were assessed 1, 24, 48 and 72 hours after treatment.

Number of animals or in vitro replicates:

2 male rabbits

Details on study design:

SCORING SYSTEM: The classification system (Kay & Calandra, 1962) was employed on this study.

TOOL USED TO ASSESS SCORE: An ophthalmoscope or pencil beam torch was available for use to facilitate inspection of the eyes.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

24/48/72 h

Score:

ca. 0

Reversibility:

fully reversible within:

Remarks:

24 hours

Remarks on result:

no indication of irritation

Remarks:

The highest total mean score was 10.0 occurring at the one hour observation, however this was fully reversible within 24 hours.

Results 2

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24/48/72 h

Score:

ca. 0

Reversibility:

not specified

Remarks on result:

no indication of irritation

Results 3

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48/72 h

Score:

ca. 0

Reversibility:

not specified

Remarks on result:

no indication of irritation

Results 4

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48/72 h

Score:

ca. 0

Reversibility:

not specified

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

Instillation of the test item gave rise to no initial pain response.

Diffuse crimson-red conjunctival appearance (Grade 2 redness), slight swelling (Grade 1 chemosis) and slight discharge (Grade 2 discharge) were apparent in both animals one hour after installation only. The treated eyes of all animals were overtly normal from 24 hours after installation.

Other effects:

There was no sign of toxicity or ill health in any rabbit during the observation period.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The highest total mean score was 10.0 occurring at the one hour observation; accordingly under the criteria 'Kay & Calandra (1962)' the test substance was classified as 'minimally irritating' to the eye. The substance does not require labelling in accordance with European Commission regulation 1272/2008 (CLP).

Executive summary:

Summary

The purpose of this study was to assess the eye irritation potential of 6 -methyl-3,4 -dihydro-2H-1,4 -benzoxazine (an industrial chemical) to the rabbit. The method followed was that described in:

- Method B5 Acute Toxicity (Eye Irritation) of Commission Regulation (EC) No. 440/2008

- OECD Test Guideline 405, 2020

Two rabbits received a single ocular installation of 0.1 mL of the test substance as supplied; the treated eyes were observed 1, 24, 48 and 72 hours after installation.

Installation of the test item gave rise to no initial pain response.

Diffuse crimson-red conjunctival appearance, slight swelling and slight discharge were apparent in the treated eyes of both animals one hour after installation only. The treated eyes of all animals were overtly normal from 24 hours after installation.

The total mean scores were assigned according to the system of 'Kay & Calandra (1962)'. The highest total mean score was ten occurring at the one hour observation; accordingly under the criteria of 'Kay & Calandra (1962)' the test substance was classified as 'minimally irritating' to the eye.

The substance does not require labelling in accordance with European Commission regulation 1272/2008 (CLP).