Registration Dossier

Administrative data

Description of key information

Skin irritation in vitro/in vivo (OECD 431/404): not corrosive/not irritating
Eye irritation in vitro/in vivo (OECD 437/405): not irritating

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Skin irritation/corrosion

To characterize the potency of the test substance to induce skin corrosion, an in vitro skin corrosion test using a three-dimensional model of the human epidermis (EpiDermTMSkin Model) was conducted according to OECD guideline 431 and the requirements of GLP (Lehmeier, 2012). The test item (25 mg) was moistened with 25 µL water and topically applied to the EpiDermTMtissue (MatTek Corporation, Ashland, USA). To assess cytotoxic effects, cell viability was determined via the MTT reduction assay 3 or 60 min after exposure to the test substance. The relative mean tissue viability compared to the negative control was 91% and 103% after 3 and 60 min, respectively. The positive control substance KOH (8 N) reduced the relative tissue cell viability to 22% or 17% after 3 or 60 min exposure, thereby fulfilling the criteria for the validity of the study. Based on these results, the test substance is considered to be non-corrosive to skin according to the classification criteria given in OECD guideline 431.

To further assess the acute skin irritation/corrosion potential of the test substance, an in vivo study in New Zealand White rabbits was performed according to OECD guideline 404 and under the conditions of GLP (Lütkenhaus, 2012). In this study, the undiluted test substance (0.5 g) was moistened with aqua ad injectionem and applied to the clipped skin of 3 female New Zealand White rabbits for 4 h under semiocclusive conditions. The scoring of skin reactions (erythema and edema) was performed 1, 24, 48 and 72 h after removal of the dressing and washing of residual test substance. Single dermal application on clipped skin did not induce any skin reactions at the application site of any animal at any of the observation time points. No mortalities and no signs of systemic toxicity were noted during the study. The mean erythema and edema scores after 24, 48 and 72 h were 0 for all 3 animals.

In addition, an acute dermal toxicity study in male and female Wistar rats at a limit dose of 2000 mg/kg bw further supported the non-irritating potential of the test substance (Holalagoudar, 2012). In this study, no erythema and edema were noted 24, 48 and 72 h post-exposure and up to the end of the 14-day observation period. The only reactions on skin included eschar formation in 1 of 5 males and 1 of 5 females during Days 6 to 8 of the observation period, but these findings were fully reversible until the end of the study. Based on these results, the test substance was not considered to be irritating to skin.

Eye irritation/corrosion

The eye irritation potential of the test substance was evaluated in an in vitro bovine corneal opacity and permeability (BCOP) test according to OECD 437 and the requirements of GLP (Lütkenhaus, 2012). Three isolated corneas were exposed to 750 µL of the test item solution at a concentration of 20% in 0.9% NaCl as vehicle for a period of 4 h using the closed-chamber method. Each three further corneas were treated with the vehicle alone or the positive control substance imidazole (20% in 0.9% NaCl) under similar conditions. Subsequent measurements after rinsing of the test substance-treated corneas revealed a mean opacity value of 10.67 and a mean permeability value of 0.013 resulting in anin vitroirritancy score (IVIS) of 10.86. The IVIS of the positive control (203.2) fell within two standard deviations of the current historical mean, thereby confirming the validity of the assay. According to the evaluation criteria given in OECD 437, 40858/ A TE is not classified as corrosive or severe irritant.

As a consequence of the negative results in the BCOP test, a further GLP-conform study was conducted according to OECD 405 to assess the eye irritation potentialin vivo(Stelter, 2012). The undiluted test substance (0.1 g) was placed into the conjunctival sac of one eye of 3 female New Zealand White rabbits. The untreated contralateral eye served as control. Scoring of irritation effects was performed approximately 1, 24, 48 and 72 h after test substance instillation. 24 h after test substance application, the treated eyes were rinsed with physiological saline. Single application of the test substance into the rabbit eye did not result in any irritant or corrosive effects. The individual mean scores for corneal and iridial effects and conjunctival chemosis after 24, 48 and 72 h were 0 for all 3 animals. The individual mean scores after 1, 24 and 48 h for the conjunctival redness could not be determined, since the test substance was a red-coloured powder that interfered with the evaluation. However, colouration was not present anymore after 72 h and individual mean scores for conjunctival redness were determined to be 0 for all 3 animals. Therefore, it was assumed that scores for conjunctival redness at the 24 and 48 h reading did not exceed the limit values according to GHS. Furthermore, no significant signs of toxicity were observed during the study. Based on these results, the test substance was not regarded to be an eye irritant.


Justification for selection of skin irritation / corrosion endpoint:
The selected study is the most adequate and reliable study based on overall quality assessment (refer to the endpoint discussion for further details).

Justification for selection of eye irritation endpoint:
The selected study is the most adequate and reliable study based on overall quality assessment (refer to the endpoint discussion for further details).

Justification for classification or non-classification

Based on the available data on skin and eye irritation, the test substance does not meet the criteria for classification according to Regulation (EC) No 1272/2008 or Directive 67/548/EEC.