Hydroxylamine-O-sulphonic acid

Endpoint summary

Description of key information

Skin 
EpiDerm in-vitro test: corrosive (BASF AG, 2003)
Corrositex in vitro test: corrosive (BASF SE, 2015)

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation / corrosion

Remarks:

in vitro

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Species:

other: in vitro

Strain:

other: in vitro

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 500 mg
- Concentration (if solution): undiluted

Duration of treatment / exposure:

up to 4 hours or until break through

Observation period:

Test substance: 3 min to 4 hours until break through
Negative control: 60 min
Positive control: continuosly until break through

Details on study design:

4 tests were performed for the test item, one test for the positive, negative and the color (blank) control. The experimental design of this study consisted of a qualification screen with the CDS (to determine if a color change can be detected) and a categorization screen (to categorize weak acids/bases and strong acids/bases), which were performed as a pretest, and a definitive Corrositex® assay.
The Corrositex® assay was evaluated on the basis of the color change of the CDS. The time that a color change was observed was recorded manually and the breakthrough times of the four replicates was used to determine the corrosive potential of the test substance. For the qualification screen, 100 mg of the test substance was added to the CDS screening tube. If the test substance failed to produce a color change in the CDS within one minute, the test substance could not be analyzed in this system, and no further testing was required.
In addition, one vial was used for the PC, NC and for the color (blank) control, each. A membrane disc coated with the biobarrier matrix was placed into one vial containing the CDS and 500 mg of the undiluted test substance was added onto the membrane disc. An electronic time clock was started with the application. The vial was observed for three minutes for any change in the CDS.
If no color change was observed within three minutes, the remaining membranes were treated with the test substance. An electronic time clock was started with each application. The vials were observed continuously for the first ten minutes. Thereafter the vials were observed for approximately ten minutes around the time points relevant for evaluation or until breakthrough of the test substance occurred. The elapsed time between test-substance application and the first change in the indicator solution (i.e. barrier penetration) was recorded.

The categorization screen was used to assess the appropriate scoring scale for the test substance. he categorization screen was performed by adding 100 mg of test substance to each tube A and B. Each tube was mixed and the resulting color observed. If required, 2 drops of the "confirm" reagent were added to tube B, the tube mixed, and the resulting color observed. The categorization kit and color chart provided by InVitro International were used to determine the category. The test substance was scored as category 1 (high acid/alkaline reserve) or category 2 (low acid/alkaline reserve)

 Breakthrough times of the test substance and the PC and NC

Test substance	Break Through Time[min:s]
	Vial 1	Vial 2	Vial 3	Vial 4	Mean
03/0169-3	5:18	5:19	4:51	4:18	4:57
Controls:
PC: Sodium hydroxide, solid	10:44	-	-	-	-
NC: 10% citric acid	NB	-	-	-	-

NB = no breakthrough within maximum observation period (60 min)

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

There are valid in vitro data available for the assessment of the skin irritation/corrosion potential of hydroxylamine-O-sulphonic acid available.

 

Skin

The potential of Hydroxylamine-O-sulphonic acid to cause dermal corrosion was assessed by a single topical application of 500 mg of the test substance to the Corrositex® Biobarrier Membrane (Corrositex® assay). The Corrositex® Biobarrier Membrane is the test system consisting of a reconstituted collagen matrix. The assay is based on the time that is required for the test substance to penetrate through the Corrositex® Biobarrier Membrane and produce a change in the Chemical Detection System (CDS). The qualification screen demonstrated that the test substance is able to react with the CDS and produce a visible color change. Therefore the membrane barrier test method was determined to be suitable for the evaluation of the corrosive potential of the test substance. A timescale category test was carried out to distinguish between weak and strong acids or bases. The test substance was assigned to timescale category 1 (having a high acid/alkaline reserve).

In the main test four Corrositex® Biobarrier Membranes were treated with the undiluted test substance. Based on the observed results and applying the evaluation criteria it was concluded, that Hydroxylamine-O-sulphonic acid shows a corrosive potential in the Corrositex® - Skin Corrosion Test under the test conditions chosen. The mean breakthrough time determined in the in vitro membrane barrier test was 4 minutes and 57 seconds. The breakthrough time indicates that the test substance has an intermediate corrosive potential and should be assigned to UN GHS skin corrosivity subcategories 1B or UN Transport Packing Group II as specified in OECD TG 435 (adopted 19 July 2006) (BASF SE, 2015).

The potential of hydroxylamin-O-sulphonic acid to cause dermal corrosion was assessed by a single topical application of 25 µl bulk volume (corresponding to about 15 mg) of the test substance to a reconstructed three dimensional human epidermis model (EpiDermTM). Two EpiDermTM tissue samples were incubated with the test substance for 3 minutes and 1 hour, each. Tissue destruction was determined by measuring the metabolic activity of the tissue after exposure using a colorimetric test. The reduction of mitochondrial dehydrogenase activity, measured by reduced formazan production after incubation with a tetrazolium salt (MTT) was chosen as suitable endpoint. The formazan production of the test substance treated epidermal tissues is compared to that of negative control tissues. The quotient of both values indicates the relative tissue viability. The EpiDerm skin corrosivity test showed the following results: The test substance is not able to directly reduce MTT. Viability of the test substance treated tissues determined after an exposure period of 3 minutes was 80 %. Viability of the test substance treated tissues determined after an exposure period of 1 hour was 9 %. Based on the observed results and applying the evaluation criteria it was concluded, that hydroxylamin-O-sulphonic acidshows a corrosive potential in the EpiDermTM skin corrosivity test under the test conditions chosen. The test method does not yet allow for the differentiation of severity of the effect. The results however indicate moderate corrosivity (BASF AG, 2003).

 

Justification for selection of skin irritation / corrosion endpoint:
GLP-conform guideline study. Estimated Klimisch Rating: 1

Justification for selection of eye irritation endpoint:
No study necessary since the test substance is classified as corrosive to the skin.

Effects on skin irritation/corrosion: corrosive

Justification for classification or non-classification

Based on the results for skin irritation (corrosive), the test substance is classified for skin irritation/corrosion as follows:

 

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008 (CLP). As a result the test substance is considered to be classified for skin or eye irritation under Regulation (EC) No 1272/2008, as amended for the sixth time in Regulation (EC) No 605/2014, as follows:

Cat. 1B, H314, causes severe skin burns and eye damage; Cat. 1, H318, causes serious eye damage.