1-naphthol

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 3 August 2016 et 15 August 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 438 (Isolated Chicken Eye 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

Test material

Test material information

Constituent 1

Reference substance name:

1-naphthol

EC Number:

201-969-4

EC Name:

1-naphthol

Cas Number:

90-15-3

Molecular formula:

C10H8O

IUPAC Name:

naphthalen-1-ol

Test material form:

solid: flakes

Details on test material:

Light cream flakes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Supplied by HFC, batch No. 7215452128
- Expiration date of the lot/batch: 30 November 2018
- Purity test date: 27 November 2018

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: stored at ambient temperature 15-25 deg Celsius
- Stability under test conditions: not specified
- Solubility and stability of the test substance in the solvent/vehicle: test item was used pure

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
The test item was used pure at 30 mg per sample

Test animals / tissue source

Species:

chicken

Strain:

other: ROSS, spring chickens

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: poultry slaughterhouse v.d. Bor (Netherlands)
- Age at study initiation: 7 weeks old
- Weight at study initiation: 1.5-2.5 kg

ENVIRONMENTAL CONDITIONS
Heads of the animals were cut off immediately after sedation of the animals by electric shock and incision of the neck for bleeding, and before they reached the next station on the process line. The heads were placed in small plastic boxes on a bedding of paper tissues moistened with isotonic saline. Next, they were transported to the testing facility. During transportation, the heads were kept at ambient temperature.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 30 mg
- Concentration (if solution): pure substance was used

NEGATIVE CONTROL
- Amount(s) applied (volume or weight with unit):30 µL

POSITIVE CONTROL
- Amount(s) applied (volume or weight with unit): 30 mg
- Concentration (if solution): neat (ground)

Duration of treatment / exposure:

10 seconds

Observation period (in vivo):

The eyes were examined at approximately 0, 30, 75, 120, 180 and 240 minutes after treatment

Duration of post- treatment incubation (in vitro):

240 minutes

Number of animals or in vitro replicates:

1 for Negative Contro
3 for Positive Control
3 for Test group

Details on study design:

SELECTION AND PREPARATION OF ISOLATED EYES
Within 2 hours after kill, eyes were carefully dissected and placed in a superfusion apparatus using the following procedure: First the eye lids were carefully removed without damaging the cornea and a small drop of Fluorescein sodium 2.0% w/v (Minims, England) was applied to the corneal surface for a few seconds and subsequently rinsed off with isotonic saline at ambient temperature. Next, the head with the fluorescein treated cornea was examined with a slit lamp microscope to ensure that the cornea was not damaged. If undamaged (e.g., fluorescein retention and corneal opacity scores of ≤ 0.5), the eye was further dissected from the head without damaging the eye or cornea. Care was taken to remove the eye ball from the orbit without cutting off the optical nerve too short. The enucleated eye was placed in a stainless steel clamp with the cornea positioned vertically and transferred to a chamber of the superfusion apparatus. The clamp holding the eye was positioned in such a way that the entire cornea was supplied with isotonic saline from a bent, stainless steel tube, at a target rate of 0.10 0.15 mL/min (peristaltic pump set at speed 5.00). The chambers of the superfusion apparatus as well as the saline were temperature controlled at approximately 32 deg Celsius (water pump set at 36.4 deg Celsius). After placing in the superfusion apparatus, the eyes were examined again with the slit lamp microscope to ensure that they were not damaged. Corneal thickness was measured using the Depth Measuring Attachment No. I for the Haag Streit slit lamp microscope, set at 0.095 mm. Corneal thickness was expressed in instrument units. An accurate measurement was taken at the corneal apex of each eye. Eyes with a corneal thickness deviating more than 10% of the average corneal thickness of the eyes, eyes showing opacity (score higher than 0.5), or were unacceptably stained with fluores¬cein (score higher than 0.5) indicating the cornea to be permeable, or eyes that showed any other signs of damage, were rejected as test eyes and replaced.

EQUILIBRATION AND BASELINE RECORDINGS
Each eye provided its own baseline values for corneal swelling, corneal opacity and fluorescein retention. For that purpose, after an equilibration period of 45-60 minutes, the corneal thickness of the eyes was measured again to determine the zero reference value for corneal swelling calculati¬ons.

NUMBER OF REPLICATES
1 for Negative Control ; 3 for Positive Control ; 3 for Test group

NEGATIVE CONTROL USED
Physiological saline

POSITIVE CONTROL USED
sodium hydroxide NaOH

APPLICATION DOSE AND EXPOSURE TIME
30 µL of negative control or 30 mg of postive control and test item were applied for 10 seconds

OBSERVATION PERIOD
240 minutes

REMOVAL OF TEST SUBSTANCE
- Volume and washing procedure after exposure period: 20 mL of saline solution was used for rinsing.
- Indicate any deviation from test procedure in the Guideline : no deviations was noticed

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: slit lamp microscope
- Damage to epithelium based on fluorescein retention: Slit lamp microscope
- Swelling: measured with optical pachymeter on a slit-lamp microscope
- Macroscopic morphological damage to the surface: No
- Others (e.g, histopathology): Histopathological examination

SCORING SYSTEM:
- Mean corneal swelling (%)
Corneal swelling, expressed as a percentage, is calculated according to the following formula:
“Corneal thickness at time t minus corneal thickness at time t = 0, divided by corneal thickness at time t = 0 and multiplied by 100”.
The mean percentage of swelling for the three test eyes will be calcula¬ted for each of the observation time points of 30, 75, 120, 180, and 240 minutes. The maximum mean percentage (can be at any of the time points) will be used for classification into one of four categories

- Mean maximum opacity score
Opacity degree of density (area most dense taken for scoring)
0 = no opacity
0.5 = very faint opacity (= very slight)
1 = scattered or diffuse areas, details of iris clearly visible (= slight)
2 = easily discernible translucent area, details of iris slightly obscured (= moderate)
3 = severe corneal opacity, no specific details of iris visible, size of pupil barely discernible (= severe)
4 = complete corneal opacity, iris invisible (= very severe)
The mean corneal opacity value for all test eyes is calculated for the observation time points of 30, 75, 120, 180, and 240 minutes. The maximum mean opacity score (can be at any of the time points) will be used for classification into one of four categorie

- Mean fluorescein retention score at 30 minutes post-treatment
0 = no fluorescein retention
0.5 = very minor single cell staining (= very slight)
1 = single cell staining scattered throughout the treated area of the cornea (= slight)
2 = focal or confluent dense single cell staining (= moderate)
3 = confluent large areas of the cornea retaining fluorescein (= severe)
Intermediate scores can also be assigned. The mean fluorescein retention value for all test eyes is calculated for the observation time point of 30 minutes only. If desired or in case of test substances that have adhered to the cornea, fluorescein retention can be determined at t=240 min or whenever the test compound is removed.

DECISION CRITERIA: please specify if the decision criteria as indicated in the TG was used.
On the basis of the severity of the observed findings for corneal swelling, corneal opacity and fluorescein retention, the effects are divided into four categories, viz. I = no effect; II = slight effect; III = moderate effect; IV = severe effect.

Interpretation of corneal swelling, corneal opacity, and fluorescein retention and categorisation into the four categories is done according the following methodology:

Corneal swelling:

Mean corneal swelling (%) Category
0 5 I
>5 12 II
>12 - 18 (>75 min. after treatment) II
(≤75 min. after treatment) III
>18 26 III
>26 - 32 (>75 min. after treatment) III
(≤75 min. after treatment) IV
>32 IV

Corneal opacity:

Max. mean opacity score Category

0.0 0.5 I
0.6 1.5 II
1.6 2.5 III
2.6 4.0 IV

Fluorescein retention:

mean fluorescein retention score Category
at 30 min after treatment:

0.0 0.5 I
0.6 1.5 II
1.6 2.5 III
2.6 3.0 IV

Results and discussion

In vitro

Results

Results 1

Irritation parameter:

percent corneal swelling

Remarks:

(in %)

Run / experiment:

Test Item

Value:

28

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Results 2

Irritation parameter:

cornea opacity score

Run / experiment:

Test item

Value:

3

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Results 3

Irritation parameter:

fluorescein retention score

Run / experiment:

Test Item

Value:

3

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Results 4

Irritation parameter:

in vitro irritation score

Run / experiment:

Test Item

Value:

148

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: No.

DEMONSTRATION OF TECHNICAL PROFICIENCY: Not specified

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes
- Acceptance criteria met for positive control: yes
- Range of historical values if different from the ones specified in the test guideline: Not specified

Any other information on results incl. tables

Table 1 - Summary results of the slit-lamp examination

Test material	Maximum mean score for:			Irritation catego­ries^1	Irritation Index^2	Classifi­ca­tions (EU-CLP^3/UN-GHS^4)
	Swelling %	Opaci­ty	Fluores­cein retention
1-Naphthol (A017; GTS119103)	28	3.0	3.0	III;IV;IV	148	1/1
NaOH(positive control)	45	4.0^5	3.0	IV;IV;IV	185	1/1

1 I = no effect; II = slight effect; III = moderate effect; IV = severe effect.

2 Irritation Index = maximum mean corneal swelling + maximum mean opacity (x 20) + mean fluorescein score (x 20)

3 EU-CLP: NC = not classified; Category 2 = Irritating to eyes; Category 1 = irreversible effects on the eye/serious damage to the eye. Regulation (EC) No 1272/2808 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2806.

4 UN-GHS: NC = not classified; Category 2B = mild irritant, causes eye irritation; Category 2A = irritant, causes eye irritation; Category 1 = irreversible effects on the eye/serious damage to the eye. United Nations-Economic Commission for Europe (UN/ECE) (2003). Globally Harmonized System of Classification and Labelling of Chemicals (GHS). UN, New York and Geneva, 2007.

5 Immediate iris constriction and severe loosening of epithelium

 

 

Table 2 - Individual histopathological findings

 

Test Material	Eye no.	Epithelium					^Notes	Stroma			Endothelium
		Erosion	Necrosis	Vacuolation†				Disorder of fibers	Pyknoticnuclei		Necrosis
				top	mid	low			outer region (adjacent to epithelium)	inner region (adjacent to endothelium)
1-Naphthol (A017; GTS119103)	1	3	3	1	1	½		-	-	-	-
	2	3	3	1	1	½		-	-	-	-
	3	3	3	1	1	½		-	-	-	-
NaOH (positive control)	13	3	3	-	-	-	‡	-	-	-	P
	14	3	3	-	-	-	‡	-	-	-	P
	15	3	-	-	-	-	‡	-	-	-	P
Saline (negative control)	16	-	-	-	-	-		-	-	-	-

 

- = not observed; P = present; ½ = very slight; 1 = slight; 2 = moderate; 3 = severe;

†= scored in the top/mid/low section of the epithelium;‡ = stromal necrosis

 

Applicant's summary and conclusion

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Remarks:

Note: harmonized classification as Eye Dam 1

Conclusions:

Under experimental conditions of this study, the test item 1-Naphthol induced severe damages to enucleated chicken eye in Isolated Chicken Eye assay which was performed according OECD Guideline 438 method. According to CLP regulation, the test item 1-Naphthol was defined as Category 1 "Irreversible effects on the eyes" based on GHS criteria.

Executive summary:

This GLP-compliant study was performed to assess the potential irritation/corrosion property of the registered substance 1-Naphthol in a Isolated Chicken Eye test (ICE test) according to OECD guideline 438 method.

1-Naphthol was evaluated neat for eye irritation potential in the Isolated Chicken Eye (ICE) test. In addition, the test included a negative control (saline) and a positive control (NaOH). Chicken eyes were obtained from slaughter animals used for human consumption. The isolated chicken eyes were exposed to a single application of 30 mg for 10 seconds followed by a 20 mL saline rinse. Three main parameters were measured to disclose possible adverse eye effects: corneal thickness (expressed as corneal swelling), corneal opacity and fluorescein retention of damaged epithelial cells. In addition, histopathology of the corneas was performed.

The test item caused moderate corneal swelling (mean swelling 28%), severe opacity (mean score 3.0) and severe fluorescein retention (mean score 3.0). Microscopic examination of the corneas revealed severe erosion (3/3 corneas) and severe necrosis (3/3 corneas) of the epithelium, and very slight (3/3 corneas; low region) or slight (3/3 corneas; top and mid region) vacuolation of the epithelium.

Under experimental conditions of this study, the test item 1-Naphthol induced severe damages to enucleated chicken eye in Isolated Chicken Eye assay which was performed according OECD Guideline 438 method. According to CLP regulation, the test item 1-Naphthol was defined as Category 1 "Irreversible effects on the eyes" based on GHS criteria.