Bis(2,4,4-trimethylpentyl)phosphinic acid

Endpoint summary

Description of key information

non-skin sensitiser

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a guinea-pig maximisation test performed according to the OECD 406 Guideline and in compliance with the GLP, twenty male Dunkin/Hartley guinea-pigs were tested to assess the skin sensitisation potential of the substance.

In a preliminary study, different concentrations of the test substance were tested in order to determine the concentrations of the test substance that would produce irritation suitable for the induction phase of the main study and the maximum non-irritant concentration by the topical route of administration for the challenge phase of the main test.

In the main study, the animals received on day 1, an intradermal injection of the test substance diluted at 0.25 % in Alembicol D (coconut oil). Freund Complete Adjuvant (FCA) was also added to the mixture to potentiate the skin sensitisation. The control group was treated in the same condition with Alembicol D and FCA only. Six days after the intradermal induction, all animals (treated and control group) were treated with Sodium Lauryl Sulphate at 10 % in petrolatum. One day after (day 7), a topical application during 24h under occlusive patch conditions of undiluted test item was performed at the same site in the treated group animals and a topical application of vehicle only was performed in the control group animals.

The first challenge test was conducted 2 weeks after the topical induction by applying the test substance on a different site at two different concentrations: 50 and 100%. A second challenge test was conducted one week later (day 28) with lower concentrations (25 and 50%). The challenge applications were performed under occlusive condition for 24h and the dermal reaction was assessed 24, 48 and 72 hours after the patch removal.

No signs of ill health or toxicity were recorded. During the induction exposure, dermal reactions were observed: necrosis after the intradermal injection of FCA and of test substance in FCA, and slight erythema after the topical application in the treated and control group. At the first challenge, dermal reactions were seen in both the control and test animals. Whilst the reactions seen for test animals were generally not more severe than those seen for the controls, the irritation seen for the control animals was considered to make precise evaluation of the test response difficult. A second challenge application was therefore carried out, one week later using lower concentrations of the test substance. At the second challenge application, there were no dermal reactions seen in any of the test or control animals. Therefore, the test substance was considered as not a skin sensitizer.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the results obtained in the guinea pig maximisation test, the test substance is not classified for skin sensitisation according to the criteria of the CLP Regulation (EC) No 1272/2008.