Ethyl 4-dimethylaminobenzoate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03 August 1987 to 17 August 1987

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

not precised

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Version / remarks:

not precised

Deviations:

no

GLP compliance:

not specified

Remarks:

The study was conducted in accordance with quality assurance procedures.

Test material

Test material information

Constituent 1

Reference substance name:

Ethyl 4-dimethylaminobenzoate

EC Number:

233-634-3

EC Name:

Ethyl 4-dimethylaminobenzoate

Cas Number:

10287-53-3

Molecular formula:

C11H15NO2

IUPAC Name:

ethyl 4-(dimethylamino)benzoate

Test material form:

other: crystalline/powdery solid

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Age at study initiation: 10 to 13 weeks
- Weight at study initiation: 2.3 to 3.0 kg
- Housing: Rabbits were individually housed in metal cages with perforated floors
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: Yes; the report states that all rabbits were acclimated to the laboratory environment

ENVIRONMENTAL CONDITIONS
- Temperature: Approximately 19 °C
- Humidity: 30 to 70 % (relative)
- Air changes: Approximately 19 per hour
- Photoperiod: 12 hours of artificial light (07.00- 19.00) in each 24 hour period

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 33 mg (occupying a volume of 0.1 mL)

Duration of treatment / exposure:

After the test material was placed into the eye, the eyelids were gently held together for one second before releasing.

Observation period (in vivo):

7 days
Examination of the eyes was carried out 1 hour and 1, 2, 3, 4 and 7 days after installation.

Number of animals or in vitro replicates:

3 animals

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Eyes were not washed

SCORING SYSTEM: Grading and scoring of the ocular lesions were performed using the prescribed numerical scoring system as follows:

- Cornea (opacity; degree of density (area most dense taken for reading))
0 = No ulcerations or opacity
1 = Scattered or diffuse areas of opacity (other than slight dulling of normal lustre), details of iris clearly visible*
2 = Easily discernible translucent areas, details of iris slightly obscured*
3 = Nacreous areas, no details of iris visible, size of pupils barely discernible*
4 = Opaque cornea, iris not discernible through the opacity*

- Iris:
0 = Normal
1 = Markedly deepened rugae, congestion, swelling, moderate circumcorneal hyperaemia or injection, any of these or a combination of any thereof, iris still reacting to light (sluggish reaction is positive)*
2 = No reaction to light, haemorrhage, gross destruction (any or all of these)*

- Redness (refers to palpebral and bulbar conjunctivae cornea and iris)
0 = Blood vessels normal
1 = Some blood vessels definitely hyperaemic (injected)
2 = Diffuse, crimson colour, individual vessels not easily discernible*
3 = Diffuse, beefy red *

- Chemosis (lids and/or nictitating membranes)
0 = No swelling
1 = Any swelling above normal (includes nictitating membranes)
2 = Obvious swelling with partial eversion of lids*
3 = Swelling with lids about half-closed*
4 = Swelling with lids more than half-closed*

* Interpreted as a positive effect

TOOL USED TO ASSESS SCORE: A handheld torch was used to aid observations

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Results 2

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

no indication of irritation

Results 3

Irritation parameter:

conjunctivae score

Remarks:

redness

Basis:

mean

Time point:

24/48/72 h

Score:

0.33

Max. score:

3

Reversibility:

fully reversible within: 48 hours

Results 4

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24/48/72 h

Score:

0.11

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Irritant / corrosive response data:

No corneal damage or iridial inflammation was observed in any of the animals. Obvious swelling with partial eversion of the eyelids was seen in one animal one hour after instillation only. Transient, mild conjunctival irritation was seen in the two remaining animals. The eyes were normal two days after instillation.
The numerical scores awarded to the ocular reactions elicited by the test material can be seen in Table 1.

Any other information on results incl. tables

Table 1: Ocular reactions elicited by the test material

Rabbit number and sex	Region of eye		One hour	Day after instillation
				1	2	3	4	7
587 Male	Cornea		0	0	0	0	0	0
	Iris		0	0	0	0	0	0
	Conjunctivae	Redness	1	1	0	0	0	0
		Chemosis	1	0	0	0	0	0
608 Male	Cornea		0	0	0	0	0	0
	Iris		0	0	0	0	0	0
	Conjunctivae	Redness	1	1	0	0	0	0
		Chemosis	2	1	0	0	0	0
610 Male	Cornea		0	0	0	0	0	0
	Iris		0	0	0	0	0	0
	Conjunctivae	Redness	1	1	0	0	0	0
		Chemosis	1	0	0	0	0	0

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

Not eye irritating

Conclusions:

Under the conditions of this study, the test material has been determined to be not irritating to the eye.

Executive summary:

A study was conducted to investigate the potential of the test material to cause eye irritation in accordance with the standardised guidelines OECD 405 and EU Test Method B.5.

Three male albino rabbits (New Zealand White strain) were treated with the instillation of 33 mg of the test material, equivalent to a volume of 0.1 mL, into the lower everted lid of one eye. The eyelids were held together for one second before releasing; the contralateral eye remained untreated and served as a control. Eyes of the test animals were examined after 1 hour and 1, 2, 3, 4 and 7 days post treatment. 

No corneal damage or iridial inflammation was observed in any of the animals. Obvious swelling with partial eversion of the eyelids was seen in one animal one hour after instillation only. Transient, mild conjunctival irritation was seen in the two remaining animals. The eyes were normal two days after instillation.

The overall mean scores for the three animals from the 24, 48 and 72 hour observations for the cornea, iris, redness and chemosis parameters were 0, 0, 0.33 and 0.11, respectively.

Under the conditions of this study, the test material has been determined to be not irritating.