Reaction product of Propanoic acid, 3-[[bis(2-methylpropoxy)phosphinothioyl]thio]-2-methyl- and tridecanamine, N-tridecyl-, branched and linear

Endpoint summary

Description of key information

The guinea pig maximization test for skin sensitization was performed because the substance is surface-active. From 10 animals in the test group, 4 showed a response to the test substance after the challenge while the 5 animals of the control group remained without a reaction after the challenge with the test substance. Based on these findings in can be concluded that the test substance has a sensitizing potential to the skin.

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The dermal sensitising potential of the test substance was investigated in a guinea pig maximisation test (GPMT) according to OECD guideline 406 (1992) and EU method B.6 (2008).

One main study was performed with 15 guinea pigs (Dunkin-Hartley) in total divided into a control group with 5 animals and a test group with 10 animals. The test concentrations for the main study were selected on the basis of the results of the preliminary investigations.

The main study started with a two-week induction phase. The animals of the test group were induced with the test item, whereas the animals of the control group were induced with the vehicle paraffin subliquidum. During the first induction, the 5 % (w/w) test item in the vehicle paraffin subliqu. and in an adjuvant solution (1:1-mixture of Freund's Complete Adjuvant (FCA) and NaCI 0.9 %) was intradermal injected in pairs into the scapular area of the animals of the test group. The vehicle or a 50 % (w/v) concentration of the vehicle in the adjuvant solution was intradermal injected in pairs in the animals of the control group. Furthermore, all animals got a third pair of intradermal injections consisting of the adjuvant solution as a 1:1-mixture of FCA and NaCI 0.9 %.

One week after the intradermal induction, 100 % (undiluted) test item was applied under occlusive conditions on the skin of the scapular area of the animals of the test group for 48 hours. The dermal induction of the control group took place with the vehicle paraffin subliqu. only. After the intradermal and dermal induction during the main study, all 15 animals of the control and test groups showed graduated skin reactions in form of erythema (grade 0 to 2) on the different injection sites. In addition, all animals showed open necrosis at different injection sites with adjuvant involvement on the day prior and after the dermal induction.

Three weeks after the first induction, the animals of the control and test groups were challenged by a 24-hour occlusive application of the 50 % (w/w) test item and the vehicle on the skin of the posterior right and left flanks, respectively. The skin reactions were assessed 24 hrs and 48 hrs after the removal of patches. During the main study, 4 of 10 test group animals (40 %) responded with skin reactions to the challenge treatment with the test item. The 5 control group animals were free of any reactions after the challenge treatment with the test item and vehicle during the main study. Due to the unambiguousness of findings, the accomplishment of a rechallenge was not necessary. Based on the results of the Guinea Pig Maximization Test (GPMT) described in this report, the test item showed a sensitizing potential to the skin.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The substance was tested in a GLP-compliant guinea pig maximization test (OECD 406). This test design was chosen because the substance is surface active. For inclusion in GHS category 1B, a substance needs to cause a senitization rate of ≥ 30 to < 60% at an intradermal induction concentration of > 0.1 and ≤ 1% or a rate of ≥ 30% at a concentration > 1%. In this case, the substance caused an induction rate of 40% after an intadermal induction concentration of 5%; therefore criteria for inclusion in GHS subcategory 1B are fulfilled.