1,2-Benzenedicarboxylic acid, di-C9-11-branched alkyl esters, C10-rich

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Sensitizing properties have not been demonstrated in humans with DIDP or similar high molecular weight phthalates.

Migrated from Short description of key information:
DIDP did not produce a sensitizing response in two guinea pig studies conducted by the methods of either Buehler (method defined by Directive 92/69/EEC B.6) or Magnusson and Kligman (Huntingdon Research Centre, 1994; Inveresk Research International, 1981, respectively). In both studies, DIDP gave negative results for sensitization with no evidence of irritating effect. Positive controls functioned appropriately.

One guinea pig study conducted according to Buehler gives a clear positive response (Exxon Biomedical Sciences, 1992). The marked response obtained in this study is inconsistent with other information. The strong irritant effect during induction phase, only observed in this assay, is also surprising, considering the minimal evidence for irritancy in other studies. Accordingly, as the results of this study are neither consistent nor plausible. The other two studies (Huntingdon Research Centre, 1994; Inveresk Research International, 1981). are considered more appropriate for assessing the sensitization potential of DIDP.

No positive reactions were reported in patch test studies conducted in humans (Medeiros et al., 1999). Consequently the evidence suggests that DIDP does not cause sensitization in humans.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Pulmonary sensitizing properties have not been demonstrated with DINP a similar high molecular weight phthalate used in read across, and no cases have been reported in humans. 

Migrated from Short description of key information:
No studies investigating the respiratory sensitization potential of DIDP have been conducted. However, the respiratory sensitizing potential of DEHP, DINP, DIHP, and BBP were evaluated by dermal application of test substances (50 ul/flank) to female B6C3F1 mice 5 times/week for 2 weeks. Trimellitic anhydride (TMA) was given once as a positive control at the last day of the 2-week induction phase. On study day 21, challenge doses (25 ul/ear) of test or control substances were applied to both ears of the mice. A week later, blood samples were collected fro measurement of total serum IgE and auricular lymph nodes for IL-4 and IL-13 proteins and their corresponding mRNAs. Treatment with phthalates did not result in significant changes in IgE, IL-4, and IL-13 proteins, and IL-4 and IL-13 mRNAs while the positive control, TMA, produced statistically significant increases in all parameters. Therefore, this study indicates that DEHP, DINP, DIHP, and BBP have little if any potential to produce antibody-mediated respiratory allergy (Butala et al., 2004). Due to the similarity in structure, it can be similarly concluded that DIDP is unlikely to produce antibody-mediated respiratory allergy.