Registration Dossier

Administrative data

Description of key information

The read-across test item CAS 68784 -08 -7 containing 39.8% active ingredient was predicted to be irritant to human skin based on the three-dimensional EST 1000 human skin model, showing a cell viability of 1.3% compared to control, which meets the 50% classification threshold). However it was negative for corrosion in the same test model (3 minutes and 1 hour exposure), showing cell viability of 101 and 78.0% versus controls, respectively, which were above threshold value of 50%. CLP classification 2 for skin irritation is proposed for the registered substance. A 5 and 10% solution were previously tested to be non-irritant based on human application to arm skin for 48 hours, and therefore these are concentration limits for non-classification. 

The read-across test item CAS 68784 -08 -7 containing 39.8% active ingredient was predicted to be irritant to human eye based on the in vitro HET-CAM model, showing an in vitro irritation score of 19, which is comparable to positive control value. However it was negative for severe eye irritation and damage in the in vitro BCOP model, showing an in vitro irritation score of 21.13, which was below classification threshold of 55.1. CLP classification 2 for eye irritation is proposed for the registered substance. A 20% solution was previously tested to be mildly irritant based on the Draize method in rabbit eyes. 

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

Assessment of skin irritation was based on a weight-of-evidence approach:

- In an in vivo (human) study, a 1 cm2 of unmedicated white lint was soaked in the 5 and 10% read-across test item solution in comparison with toilet soaps, and applied to the skin of the left arm of 4 volunteers for 48 hours under waterproof adhesive dressing, followed by an observation period of 72 hours (Baker Research Laboratories limited, 1962a). No reactions were detected.

- In a first in vitro study, the corrosive properties of read-across substance CAS 68784 -08 -7 were studied in an experiment with a three-dimensional EST-1000 human skin model (Flügge, 2013a). The test item (containing 39.8% active ingredient) was applied for exposure times of 3 minutes or 1 hour. The mean viability of cells exposed to the test item was 101.0% after a 3-minute exposure period and 78.0% after a 1-hour exposure. These values were well above the cut-off percentage cell viability values distinguishing corrosive from non-corrosive test items of <50% or <15% for a 3-minute or 1-hour treatment, respectively. Therefore, the test item was non-corrosive in this human skin model and is predicted to be non-corrosive to human skin.

- In a second in vitro study, the irritant properties of read-across substance CAS 68784 -08 -7 to skin cells were also studied in an experiment with a three-dimensional EST-100 human skin model (Flügge, 2013b). The test item (containing 39.8% active ingredient) was applied for an exposure time of 20 minutes, followed by refreshment of the medium and further 42 hours incubation. The mean viability of cells exposed to the test item was 1.3% of the negative controls and, hence, below the 50% cut-off value. The test item was considered to be cytotoxic and is predicted to be irritant to skin in accordance with UN GHS category 2.

- According to ECHA progress report 2010 (p. 32), it is accepted that in vitro methods for skin irritation represent a full replacement of the in vivo method in a tiered testing strategy and in conjunction with in vitro skin corrosivity tests, if necessary. A positive result in the human skin model for irritation does not need to be confirmed by additional testing and shall lead to classification.

 

Assessment of eye irritation was also based on a weight-of-evidence approach:

- In an in vivo study, the potential eye irritation properties of different samples were tested according to the Draize mehod in rabbits (Baker Research Laboratories limited, 1962b). The test solutions were diluted with distilled water so that the content of active matter was reduced to 20% in each case. 0.1mL of the read-across test solution (20% act. ingr.; CAS 68784 -08 -7) was instilled into the conjunctival sac of one eye of each rabbit, the other eye serving as a control (3 rabbits were used). Readings were made visually and with the aid of an ophthalmoscope at 1, 2, 4, 6, 24, 48, 72 hours and 4 and 7 days after instillation and evaluated according to the Draize scoring method. Mild irritation was observed which was reversible within 3 days, which was below threshold of classification.

- In a first in vitro study the eye irritancy potential of read-across test item containing 39.8% active ingredient (CAS 68784 -08 -7) was tested by means of the chorioallantoic membrane of hens' eggs (HET-CAM) method (Haferkorn, 2012). Three eggs each were treated with 300 µL/egg. After administration of the test item, blood vessels including the capillary system and the albumen were examined and scored for irritant effects (haemorrhage, coagulation and lysis) during 5 minutes. The test item treated eggs revealed a pronounced effect with an irritation index (IS) of 18.6, compared to IS of 19.4 or 10.0 for 0.1% NaOH and 1% SDS positive controls and no effects in the negative control 0.9% NaCl solution. The read-across test item CAS 68784 -08 -7 was predicted to be irritating.

- In a second in vitro study severe eye irritancy potential and corrosivity potential of the read-across test item containing 39.8% active ingredient (CAS 68784 -08 -7) was tested by means of the BCOP test method (Leuschner, 2013). Three corneas were used for each treatment group (test item, negative and positive controls). The test item was used as a 3.98-fold dilution in 0.9% NaCl-solution in order to obtain a 10% w/v dilution of active ingredient, which complies with the guideline requirements for surfactants. 0.9% NaCl solution was used as the negative control and 1% NaOH solution as the positive control item. An IVIS score of 21.90 was calculated, hence the read-across test item was not classified as a severe irritant and not corrosive, based on the results of this test. The corneas treated with the positive control item 1% NaOH solution revealed an IVIS score of 87.43 was well above the cut-off value of 55.1 and, hence, the acceptance criteria for the test were fulfilled. The read-across test item, containing 39.8% active ingredient was consequently not classified as a severe irritant and is not corrosive.

- According to Column 2, the criteria for classification are met as irritating to eyes, based on weight of evidence, and furtherin vivotesting was therefore not needed.

 

Conclusion

- A subgroup CLP category 2 classification was decided for skin irritation, with concentration limit of 10% for non-classification of registered substance.

- A subgroup CLP category 2 classification was decided for eye irritation, with concentration limit of 20% for non-classification of registered substance.

- More information on the subgroup classification is provided in the read-across justification, separately attached in Section 13.

 

Justification for selection of skin irritation / corrosion endpoint: Although the in vitro study for irritation was selected, the corrosion study was equally valuable in a weight-of-evidence approach. 

Justification for selection of eye irritation endpoint: Although the BCOP study was selected, the HET-CAM and in vivo studies were equally valuable in a weight-of-evidence approach. 

Justification for classification or non-classification

The registered substance is classified for skin irritation according to the CLP regulation (No. 1272/2008 of 16 December 2008) as Category 2, with signal word 'warning' and hazard statement: H315 - Causes skin irritation. However, a concentration limit of 10% for non-classification can be applied.

For the eye, the test substance is classified as irritating to eyes according to CLP regulation as Category 2, with signal word 'warning' and hazard statement: H319 -Causes serious eye irritation. However, a concentration limit of 20% for non-classification can be applied.