Aminoiminomethanesulphinic acid

Endpoint summary

Description of key information

Skin irritation/corrosion: OECD 431, not corrosive;

Skin irritation/corrosion: Patch test, skin irritant,

Eye irritation/corrosion: FDA guideline, corrosive

Respiratory irritation: With a maximum 5% content of thoracic fraction, a classification of total TDO as STOT SE3, H335 - May cause respiratory irritation (Xi, R37 - Irritating to respiratory system) is adequate, based on expert judgement (see Acute toxicity section)

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation

An in vitro study was performed to assess the corrosive potential of aminoiminomethanesulphinic acid (CAS 1758 -73 -2) by means of the Human Skin Model Test with EpiDerm™ tissues models (Heppenheimer, 2012)

Independent duplicate tissues of EpiDerm™ were exposed to the test item, the negative control (deionised water) or the positive control (8.0 N KOH) for 3 minutes and 1 hour, respectively.

25 mg of the test item were applied to each of the tissues, wetted with 25 µL of deionised water, and spread evenly over the surface of the tissue. After exposure to the negative control the absorbance values met the required acceptability criterion of a mean OD570 ≥ 0.8 for both treatment intervals thereby confirming the acceptable quality of the tissues.

Exposure to the positive control induced a decrease in the relative absorbance as compared to the negative control, both for the 3 min exposure period and for the 1 h exposure period thus confirming the validity of the test system and the specific batch of tissue models.

After exposure to the test item the mean relative absorbance value decreased to 93.5% after 3 min exposure. After 1 hour exposure the mean relative absorbance value was reduced to 88.2%. Both values did not exceed the threshold for corrosivity which is defined to be 50% after the 3 min exposure and 15% after the 1 h exposure. After exposure to the negative and positive control for 3 min the relative absorbance values were 100% and 9.2% respectively. After exposure to the negative and positive control for 1 h the relative absorbance values were 100% and 3% respectively. Therefore, the test item was not considered to be corrosive.

Thus, the test substance proved to be non-corrosive to skin under the reported experimental conditions.

A skin irritation study was performed in 12 New Zealand white rabbits by means of a Patch test on the abraded and intact skin of rabbits. 0.5 g of the test compound (a 40% water solution) was applied under a surgical patch and left in place for 24 h. At 24 and 48 h after treatment lesions were evaluated according to Draize scoring method.

In animals with intact skin a very slight or well-defined erythema and a very slight edema were observed at 24 h. In the same group a very slight or well-defined erythema, very slight or slight ischemia and a very slight or slight edema were noted at 72 h reading point.

In animals with abraded skin well-defined or moderate erythema, very slight or slight ischemia (especially on abrasions) and a very slight to moderate edema were observed at 24 h reading point.

In the same group of animals well-defined or moderate erythema, slight to distinct ischemia and very slight or slight edema were observed at 72 h reading point.

The mean erythema score out of six animal was 1.5 and the mean edema score out of sex animals was 0.61. No information is available about the reversibility of the effects.

Due to the short observation period in this study and in combination with the tendency of the irritating effects, the result of the study conducted with a 40% water solution was considered to be skin irritating.

 

 

Eye irritation

The eye irritation properties of aminoiminomethanesulphinic acid (CAS 1758-73-2) were tested in according to procedures published by the FDA (1963) and Draize and Kelley (1952). 6 New Zealand white rabbits received a treatment with 100 mg of the test compound on the everted lower lid of one eye. After 24h the effects on eye caused by the test material generally consisted of slight opacity of the cornea, slight iritis (3/6 animals), and moderate redness and slight to severe swelling of conjuctivae. In the course of 7–day observation period some of these eye effects recovered partly or completely.

However, after 7 days slight of moderate to severe corneal opacity and vascularization on the cornea were observed in 4/6 rabbits, ulcus cornea in 2/6 animals, slight iritis in 3/6 rabbits and slight lesions of the conjuctivae in all six animals.

The mean cornea, iris, conjunctivae and chemosis scores out of six animals were 1.22, 0.6, 2 and 2 respectively. Thus, it is concluded that according the test substance was a severe eye irritant.

Justification for selection of skin irritation / corrosion endpoint:

Hazard assessment is conducted by means weight of evidence approach

Justification for selection of eye irritation endpoint:

There is only one study available.

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: corrosive

Effects on respiratory irritation: irritating

Justification for classification or non-classification

The available data on skin irritation of aminoiminomethanesulphinic acid (CAS 1758-73-2) meet the criteria for classification for skin irritation category 2 (H315) according to Regulation (EC) No 1272/2008 and as skin irritating (Xi; R38) according to Directive 67/548/EEC.

 

The available data on eye irritation of aminoiminomethanesulphinic acid (CAS 1758-73-2) according to Regulation (EC) No 1907/2006, Annex XI, 1.5 meet the criteria for classification for eye dam. category 1 (H318) according to Regulation (EC) No 1272/2008 and as risk of serious damage to eyes (Xi; R41) according to Directive 67/548/EEC.