Asparagine

Endpoint summary

Description of key information

Study according to OECD Test Guideline 439, GLP, in the EPISKIN-SM™ model, the mean relative tissue viability (% negative control) was > 50% (98.8%) after 15 min treatment and 42 h post-incubation.

Study according to OECD Test Guideline 492, GLP,  three-dimensional  reconstructed  human  cornea-like  epithelium  (RhCE) EpiOcular™ (MatTek), the mean relative tissue viability (% negative control) was > 60% (79.2%).  

Respiratory irritation: No study available, inhalation is not the expected route of exposure.

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 (in vitro):

In an in vitro skin irritation study according to OECD Test Guideline 439, GLP compliant, the EPISKIN-SM™ reconstructed human epidermis model (SkinEthic) which consists of normal human epidermal keratinocytes (NHEK) was exposed to L-asparagine for 15 min and subsequently incubated for 42h. After the incubation period the cytotoxicity was measured using the MTT test system. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT after the incubation period and compared to those of the concurrent negative controls. The test is considered valid if the mean relative tissue viability (% negative control) is > 50%. The mean relative tissue viability (% negative control) was 98.8% after 15 min treatment and 42 h post-incubation. Thus, L-asparagine is considered to be not irritating to the skin.

 

Eye irritation (in vitro):

In an in vitro eye irritation study according to OECD Test Guideline 492, GLP compliant, the test uses the three-dimensional reconstructed human cornea-like epithelium (RhCE) EpiOcular™ (MatTek) which was incubated with the test item for 6h and subsequently incubated without test item (post-incubation period). After the incubation period the cytotoxicity was measured using the MTT test system. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT after the incubation period and compared to those of the concurrent negative controls. The test is considered to be valid if the mean relative tissue viability (% negative control) is >60%. The mean relative tissue viability was 79.2%. Thus, L-asparagine is considered to be not irritating to the eyes.

 

Respiratory irritation:

No data on the respiratory irritation of L-asparagine are available.

There are no data gaps for the endpoint irritation/corrosion. No human information is available for this endpoint. However, there is no reason to believe that these results would not be applicable to humans.

 

Justification for classification or non-classification

Skin irritation was determined with the EPISKIN-SM™ reconstructed human epidermis model (SkinEthic) which consists of normal human epidermal keratinocytes (NHEK) and therefore represents in vitro the target organ of the species of interest and closely mimics the biochemical and physiological properties of the upper parts of the human skin, i.e. the epidermis.

This test method is able to detect chemicals that cause skin irritation, i.e. produce reversible damage to the skin and allows for hazard identification in accordance with UN GHS “Category 2”. Depending on the regulatory framework it can also be used to identify non-classified chemicals. Similarily, eye irritation was determined using the  three-dimensional  reconstructed  human  cornea-like  epithelium  (RhCE) EpiOcular™ (MatTek), which is recommended to identify chemicals that do not require classification for eye irritation or serious eye damage according to UN GHS (UN GHS “No Category”) without further testing  within  a  tiered  testing  strategy  from  those  requiring  classification  and  labelling. Thus, both in vitro systems are applicable and reliable for testing of an irritation potential.

Based on the available, relvant and adequate data the substance does not need to be classified according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System for Classification and Labeling of Chemicals (GHS) with respect to irritation/corrosion.