Human systemic exposure to [C-[14]-paraphenylenediamine-containing oxidative hair dyes: Absorption, kinetics, metabolism, excretion and safety assessment

摘要

Systemic exposure was measured in humans after hair dyeing with oxidative hair dyes containing 2.0% (A) or 1.0% (B) [C-14]-p-phenylenediamine (PPD). Hair was dyed, rinsed, dried, clipped and shaved; blood and urine samples were collected for 48 hours after application. [C-14] was measured in all materials, rinsing water, hair, plasma, urine and skin strips. Plasma and urine were also analysed by HLPC/MS/MS for PPD and its metabolites (B). Total mean recovery of radioactivity was 94.30% (A) or 96.21% (B). Mean plasma C-max values were 132.6 or 97.4 ng [C-14]-PPDeq/mL, mean AUC(0-infinity) values 1415 or 966 ng [C-14]-PPDeq/mL*hr in studies A or B, respectively. Urinary excretion of [C-14] mainly occurred within 24 hrs after hair colouring with a total excretion of 0.72 or 0.88% of applied radioactivity in studies A or B, respectively. Only N,N'-diacetylated-PPD was detected in plasma and the urine. A TK-based human safety assessment estimated margins of safety of 23.3- or 65-fold relative to respective plasma AUC or C-max values in rats at the NOAEL of a toxicity study. Overall, hair dyes containing PPD are unlikely to pose a health risk since they are used intermittently and systemic exposure is limited to the detoxified metabolite N,N'-diacetyl-PPD. (C) 2015 Elsevier Ltd. All rights reserved.