Sodium hydroxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

other: Data sharing dispute

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Test conducted according to guideline similar to OECD guideline 435 In Vitro Membrane Barrier Test Method for Skin Corrosion, however the concentration of NaOH tested is not reported (only the volume of the formulation tested is reported)

Data source

Reference

Reference Type:

publication

Title:

Comparison of In Vivo (Draize Method) and In Vitro (Corrositex Assay) Dermal Corrosion Values for Selected Industrial Chemicals

Author:

Stobbe JL, Drake KD, Maier KJ

Year:

2003

Bibliographic source:

International Journal of Toxicology, 22;99-107

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 435 (In Vitro Membrane Barrier Test Method for Skin Corrosion)

Deviations:

yes

Remarks:

The concentration of NaOH tested is not reported

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Sodium hydroxide

EC Number:

215-185-5

EC Name:

Sodium hydroxide

Cas Number:

1310-73-2

Molecular formula:

HNaO

IUPAC Name:

sodium hydroxide

In vitro test system

Test system:

artificial membrane barrier model

Source species:

other: Corrositex assay (in vitro membrane barrier test method for skin corrosion)

Details on test system:

Corrositex assay:
- glass vials which contain the chemical detection system covered by a biobarrier membrane disc, it is an amber-colored liquid composed of water and two pH indicator dyes (one basic indicator, phenyl red, and one acidic indicator, methyl orange)
- the biobarrier consists of a cellulose membrane covered with a collagen gel

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): an aliquot (500 µl) of the test material is placed on the biobarrier membrane

Duration of treatment / exposure:

The time to an observed change in either the color or consistency in the chemical detection system is determined.

Number of replicates:

4 replicate biobarrier membranes and chemical detection system assemblies

Test system

Details on study design:

TEST CONDITIONS:
- prior to conducting tests: all formulations were qualified, categorized, and classified:
qualification: direct addition of the test substance to the chemical detection system to verify that the test substance will cause a change in the chemical detection system and is herefore compatible with the Corrositex assay.
categorization: determines the appropriate cut-off times for correct classification of the formulation by adding 150 µl of the test substance to two buffer solutions to categorize the test formulation as acidic (pH 0 to 7) or basic (pH 7 to 14). The color change occurs if the test substance changes either of the two buffer solutions by greater than 1.0 pH units. The resulting color change was compared to the corresponding color charts on the Corrositex testing protocol poster (In Vitro International 1995) classification: to classify the formulations, 500 µl of the selected formulation were placed on each of four replicate biobarrier membranes and chemical detection system assemblies. The start time for each replicate was recorded, and the vials observed unitl a change in the CDS occurred. The breakthrough time was recorded for each of the four replicates. The average time was compared to the packing group assignment table, and the classification (as corrosive or noncorrosive, and packing group assignment) determined and recorded.

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

penetration time (in minutes)

Value:

13.6

Any other information on results incl. tables

Results of the Corrositex assay (break through time in min):

FCN	Corrositex category	Break through time (min) Average ± SD (upper CL, lower CL)	PG (in vitro)	PG (in vivo)	Prediction
24	1	13.16 ± 0.06 (13.35, 12.96)	II	II	C

FCN: formulation code number
SD: 1 standard deviation
CL: certified limit
PG: packing group number
C: in vitro correctly predicted

Applicant's summary and conclusion

Interpretation of results:

Category 1 (corrosive) based on GHS criteria

Remarks:

500 µL of a water-based formulation containing sodium hydroxide; breakthrough time of 13.16 min ± 0.06