Venkatesan Gopalakrishnan, Dancik Yuri, Sinha Arup, Kyaw Hpone Myint, Srinivas Ramasamy, Dawson Thomas L, Bigliardi Mei, Bigliardi Paul, Pastorin Giorgia
Department of Pharmacy, National University of Singapore, Lower Kent Ridge Road, 18 Science Drive 2, 117543, Singapore.
Skin Research Institute of Singapore, 8A Biomedical Grove, #06-06, Immunos, 138648, Singapore; Le Studium Loire Valley Institute of Advanced Studies, 1 rue Dupanloup, 45000 Orléans and EA 6295 NanoMédicaments et NanoSondes, Faculté de Pharmacie, Université de Tours, 31 Avenue Monge, 37200 Tours, France.
J Hazard Mater. 2021 Jan 15;402:123712. doi: 10.1016/j.jhazmat.2020.123712. Epub 2020 Aug 19.
Most of the permanent hair dye products contain p-phenylenediamine (PPD), a well-known skin sensitizer. PPD may cause cutaneous reactions and leads to allergic contact dermatitis (ACD), a condition with major medical and financial repercussions. Hair dye-induced ACD represents a growing concern both for consumers and the cosmetics industry. In this study we introduced novel side chains on the PPD molecule with the goal of overcoming the hazard potential of PPD. Our strategy relies on the replacement of the colorless PPD with new, larger and intrinsically colorled PPD derivatives to reduce dermal penetration and thus the skin sensitization potential. We synthesized two oligomers with bulky side-chains, which displayed 7-8 times lower cytotoxicity than PPD, a significantly weaker sensitization potential (22.0 % and 23.8 % versus 55.5 % for PPD) in the Direct Peptide Reactivity Assay, minimal cumulative penetration through excised skin and an intrinsic ability to colour and preserve the nuance when applied on bleached hair. The lower skin permeation and sensitizing potential are absolutely crucial and give a clear advantage of our products over other standards. These novel PPD hair dyes show significantly less hazard potential than PPD and may, upon further risk assessment studies, replace PPD in consumer care products.
大多数永久性染发剂产品都含有对苯二胺（PPD），一种知名的皮肤致敏剂。PPD可能会引起皮肤反应并导致过敏性接触性皮炎（ACD），这是一种会造成重大医疗和经济影响的病症。染发剂引起的ACD日益受到消费者和化妆品行业的关注。在本研究中，我们在PPD分子上引入了新的侧链，目的是克服PPD的潜在危害。我们的策略是用新的、更大且本身无色的PPD衍生物取代无色的PPD，以减少皮肤渗透，从而降低皮肤致敏潜力。我们合成了两种带有庞大侧链的低聚物，它们的细胞毒性比PPD低7 - 8倍，在直接肽反应性试验中的致敏潜力明显较弱（分别为22.0%和23.8%，而PPD为55.5%），对切除皮肤的累积渗透极小，并且在应用于漂白头发时具有染色和保持色调的内在能力。较低的皮肤渗透性和致敏潜力至关重要，使我们的产品相对于其他标准具有明显优势。这些新型PPD染发剂的潜在危害明显低于PPD，经过进一步的风险评估研究后，可能会在个人护理产品中取代PPD。
