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Description of key information

Based on the results of the key study, the dermal absorption of the test article through human skin was quantified at 0.23% and 0.28% of applied dose for oxydative and semi-permanent formulation respectively. The dermal penetration rate was considered as low.

Key value for chemical safety assessment

Absorption rate - dermal (%):

Additional information

One key study is available to assess the dermal penetration of the test article :

Toner, 2005, OECD 428 guideline, GLP compliant, Klimisch 1 :

The Test Item was evaluated for skin absorption. The 4-amino-3-nitrophenol was incorporated into a typical semi permanent hair dye formulation at 1% or typical oxydative hair dye formulation at 3%. [14C]-4-Amino-3-Nitrophenol was applied in two test preparations (oxidative and semi-permanent) to human split-thickness skin membranes mounted in flow-through diffusion cells in vitro. Both oxidative and semi-permanent hair dye test preparations were applied at a target application rate for the formulation of ca 20 mg/cm2. Absorption was assessed by collecting receptor fluid (PBS) samples hourly from 0-24 h post dose (flow rate 1.5 mL/h). At 30 min post dose, the skin was washed. Counting and the remaining samples were analysed by combustion/ liquid scintillation counting. At 24 h post dose the underside of the skin was rinsed with receptor fluid. The skin was then removed from the flowthrough cells, dried and the stratum corneum removed by tape stripping. The remaining skin was divided into exposed and unexposed skin. All liquid samples were analysed by liquid scintillation.

Under the present experimental conditions, for [14C]-4-Amino-3-Nitrophenol in the semi-permanent test preparation, most of the applied dose was removed at 30 min post dose (95.41% of the applied dose). At 24 h post dose, a further 1.06% was removed. Therefore, the dislodgeable dose was 96.47% of the applied dose. At 24 h post dose, the absorbed dose and dermal delivery were 0.23% (0.49 μg equiv/cm2) and 0.28% (0.59 μg equiv/cm2) of the applied dose, respectively.