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Title: Introduction of a methoxymethyl side chain into p-phenylenediamine attenuates its sensitizing potency and reduces the risk of allergy induction

The strong sensitizing potencies of the most important primary intermediates of oxidative hair dyes, p-phenylenediamine (PPD) and p-toluylenediamine (PTD, i.e. 2-methyl-PPD) are well established. They are considered as the key sensitizers in hair dye allergic contact dermatitis. While modification of their molecular structure is expected to alter their sensitizing properties, it may also impair their color performance. With introduction of a methoxymethyl side chain we found the primary intermediate 2-methoxymethyl-p-phenylenediamine (ME-PPD) with excellent hair coloring performance but significantly reduced sensitizing properties compared to PPD and PTD: In vitro, ME-PPD showed an attenuated innate immune response when analyzed for its protein reactivity and dendritic cell activation potential. In vivo, the effective concentration of ME-PPD necessary to induce an immune response 3-fold above vehicle control (EC3 value) in the local lymph node assay (LLNA) was 4.3%, indicating a moderate skin sensitizing potency compared to values of 0.1 and 0.17% for PPD and PTD, respectively. Finally, assessing the skin sensitizing potency of ME-PPD under consumer hair dye usage conditions through a quantitative risk assessment (QRA) indicated an allergy induction risk negligible compared to PPD or PTD. - Highlights: • Methoxymethyl side chain in p-phenylenediamine reduces its strong skin sensitizing properties. • Reduced proteinmore » reactivity and dendritic cell activation. • Reduced skin sensitizing potency in local lymph node assay (LLNA). • Negligible allergy induction risk under hair dye usage conditions.« less
Authors:
 [1] ;  [2] ;  [3] ; ;  [1] ;  [2] ;  [3]
  1. The Procter and Gamble Co., Central Product Safety and Communications, Darmstadt (Germany)
  2. The Procter and Gamble Co., Central Product Safety, Cincinnati, OH (United States)
  3. Dept. of Environmental Toxicology, Trier University, Trier (Germany)
Publication Date:
OSTI Identifier:
22285600
Resource Type:
Journal Article
Resource Relation:
Journal Name: Toxicology and Applied Pharmacology; Journal Volume: 274; Journal Issue: 3; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
60 APPLIED LIFE SCIENCES; ALLERGY; COLOR; DERMATITIS; DYES; HAIR; HYDROGEN PEROXIDE; LYMPH NODES; METABOLISM; RISK ASSESSMENT