Evaluation of skin sensitization response of dialkyl (C6-C13) phthalate esters

Isolated case reports suggest that dermal contact with some phthalate ester s may result in skin sensitization. This issue was investigated in guinea p ig sensitization tests, but the results were inconclusive. Consequently, 7 dialkyl phthalate esters, (diisohexyl, diisoheptyl, di(2-ethylhexyl), diiso nonyl, diisodecyl, diundecyl and ditridecyl phthalates), ranging in carbon number from C-6 to C-13, were tested in a 104-person panel human repeated i nsult patch test (HRIPT) using the modified Draize procedure. Test concentr ations of 100% were selected for the induction and challenge phases of the HRIPT based upon a 24-h occluded irritation test on 15 panelists. Under the conditions of this HRIPT, no evidence of dermal irritation or sensitizatio n for any of the 7 phthalate ester's was observed in the 104-person panel. These HRIPT data provide evidence for the lack of experimental skin sensiti zation potential for the phthalate esters tested.