Pyrimido[5,4-g]pteridine-2,4,6,8-tetramine, 4-methylbenzenesulfonate (1:1)

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Additional information:

Reasons for read across

The substance was not tested for skin or respiratory sensitisation. The test item is a mixture which consist mainly of the end product (app. 50 %) and a by product (app. 30 %) as well as of different impurities and isomers of the end product. Therefore, information about sensitisation are derived from studies with the end product and the by product. Moreover, one toxicological relevant impurity exceeds 1 % and is also taken into account for this summary.

 

Performance and observations

There is a reliable study available to assess the skin sensitising potential of the end product.

In order to assess the cutaneous allergenic potential under GLP conditions, a Maximisation-Test was performed in 15 (10 test and 5 control) female albino guinea pigs, in accordance with OECD Guideline 406. Test substance (purity: 94.8 %) concentrations selected for the main study were based on the results of a preliminary study. In the main study, ten experimental animals were intradermally injected with a 2 % concentration and epidermally exposed to a 50% concentration. Five control animals were similarly treated, but with vehicle alone (water). Approximately 24 hours before the epidermal induction exposure all animals were treated with 10 % SDS. Two weeks after the epidermal application all animals were challenged with a 50 % test substance concentration and the vehicle. A second challenge was performed one week later with the same test substance concentration and the vehicle.

After the first and second challenge, skin reactions of grade 1 were observed in one experimental and one control animal in response to the 50 % test substance concentration. Yellow staining was observed at the test substance treated skin sites, 24 and 48 hours after challenge first and second challenge.

 

The by product was tested for its allergic potential in a Maximization study according OECD guideline 406. 15 female guinea pigs (10 test group, 5 control group) were intradermal (0. 2 %) and epidermal (20 %) induced with the test substance solved in 0.9 % sodium chlorine. Two weeks after topical induction animals were dermal challenged with 10% of the test item (24h).

The substance did not induce any allergic reaction to skin. Neither erythema nor oedema were observed.

 

Information about sensitisation by the impurity is not available.

 

Discussion

Dermal application of the end product onto guinea pig skin caused formation of erythema. Since comparable skin reactions were observed in one control animal and based on the inconsistency in results, it was considered that all reactions observed were signs of non-specific irritation. These results indicate a sensitisation rate of 0 per cent.

 

Exposure of the by product to skin did not induce an allergic reaction.

 

Neither the end product nor the by product reveals an allergic potential. These results indicate that the mixture does not induce skin sensitisation.

 

Migrated from Short description of key information:
The allergic potential of this mixture is derived from toxicological information about the endproduct, the main by product and one toxicological relevant impurity. A GLP-conform maximization test in guinea pigs according OECD guideline 406 was performed with the end product Skin sensitisation by the test substance was not observed. The by product was also tested in a GLP conform Maximization study according OECD guideline 406. Application of the by product did not induce an allergic reaction. These results indicate that the mixture does not induce skin sensitisation.

Respiratory sensitisation

Endpoint conclusion

Additional information:

Migrated from Short description of key information:
The test item is a solid mixture. Therefore, sensitisation by inhalation is most unlikely.