2-(2-naphthyloxy)ethanol

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18 January 2012 to 09 July 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in accordance with current guideline and GLP compliant.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Deviations:

no

Principles of method if other than guideline:

N/A

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-(2-naphthyloxy)ethanol

EC Number:

202-228-8

EC Name:

2-(2-naphthyloxy)ethanol

Cas Number:

93-20-9

Molecular formula:

C12H12O2

IUPAC Name:

2-(2-naphthyloxy)ethanol

Details on test material:

- Name of test material (as cited in study report): Naphthoxyethanol
- Lot/batch No.: E00173-186
- Physical state: solid
- Analytical purity: 98.5%
- Expiration date of the lot/batch: 31 July 2013

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

OECD TG 439

Value:

> 50

Remarks on result:

other:

Remarks:

Exposure to Naphthoxyethanol resulted in a mean EpiSkin® viability of 91.77% ±2.70% ofthe negative control value.

Any other information on results incl. tables

MTT Direct Reduction Test (Preliminary Assay)

 

The test was scored by visual assessment of the formation of purple-coloured formazan. The positive control eugenol reduced the MTT solution to purple-coloured formazan. The negative controlwater did not reduce MTT to formazan after 3 h incubation. The test item,Naphthoxyethanol, did not reduce MTT to formazan after 3 h incubation.

 

EpiSkin® Irritation Test

Percentage Viability of EpiSkin® Tissues After ca 42h Recovery Time

Treatment	Mean viability per tissue (%)	Mean viability per test item (%)	SD (%)
2-Naphthoxyethanol	94.54	91.77	2.70
	89.16
	91.60
Aqueous SDS Solution (5%, w/v) (Positive Control)	6.20	10.52	3.91
	13.83
	11.54
PBS Solution (Negative Control)	95.36	100.00	4.87
	99.58
	105.07

The negative control results were similar for the three viable EpiSkin® units dosed with Dulbecco’s PBS. Exposure to Dulbecco’s PBS resulted in a mean EpiSkin® viability of 100.00% ±4.87%.

 

The positive control results were similar for the three viable EpiSkin® units dosed with aqueous SDS solution (5%, w/v). Exposure to aqueous SDS solution (5%, w/v) resulted in amean EpiSkin® viability of 10.52% ±3.91%.

 

The results were similar for the three viable EpiSkin® units dosed with Naphthoxyethanol.Exposure to Naphthoxyethanol resulted in a mean EpiSkin® viability of 91.77% ±2.70% ofthe negative control value.

 

The test item was considered to be irritant to skin in accordance with GHS category 2 if the tissue viability after exposure and post-treatment incubation was less than or equal (=) to 50%.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: OECD GHS

Conclusions:

Naphthoxyethanol was demonstrated to be non-irritant when tested in the EpiSkin® in vitro irritation assay.

Executive summary:

Evaluation of skin irritation is part of the Human Health Hazard Assessment required for registration of a chemical. In this study, the irritation potential of Naphthoxyethanol was evaluated using the SkinEthic EpiSkin in vitro irritation assay. Prior to the conduct of the irritation assay, a preliminary test was conducted to assess the intrinsic ability of the test item to reduce methylthiazoldiphenyl-tetrazolium bromide (MTT) to formazan. Naphthoxyethanol did not reduce MTT to formazan. The dermal irritation potential was assessed by applying 10 mg ± 2 mg of the solid Naphthoxyethanol to the exposed surface of three EpiSkin reconstructed human epidermis (RhE) units for 15 min. Prior to applying the test item, the EpiSkin surface was pre-moistened with sterile, ultra-pure water (5 µL). The surface area of the EpiSkin was 0.38 cm2, therefore the application rate was ca 26.3 mg/cm2. After the 15 min exposure period, the test item was washed from the surface of the EpiSkin using Dulbecco’s phosphate-buffered saline (PBS). The EpiSkin was then incubated for a recovery period of ca 42 h in a humidified incubator, set to maintain temperature and CO2 levels of 37°C and 5%, respectively. Following incubation, the EpiSkin units were transferred to assay medium containing MTT (0.3 mg/mL) and returned to the incubator for 3 h. Biopsies of the EpiSkin membranes were removed, added to acidified isopropanol, and refrigerated for ca 69 h in order to extract the

formazan. The formazan production (cell viability) was assessed by measuring the optical density of the extracts at a wavelength of 550 nm. Three replicates of the positive control, aqueous sodium dodecyl sulphate (SDS) solution (5%, w/v) (10 µL), and the negative control, PBS (10 µL) were tested in parallel to demonstrate the efficacy of the assay. The viability of each individual EpiSkin tissue was calculated as a percentage of the mean negative control viability (defined as 100%). Exposure to Naphthoxyethanol resulted in a mean EpiSkin viability of 91.77% ± 2.70% of the negative control value. Exposure to the positive control, aqueous SDS solution (5%, w/v), resulted in a mean EpiSkin viability of 10.52% ± 3.91% of the negative control value. In conclusion, Naphthoxyethanol was demonstrated to be non-irritant when tested in the EpiSkin in vitro irritation assay.