Weakening of the Transdermal Effect of p-Phenylenediamine Pigments by the Temperature-Sensitive Poloxamer Sodium Alginate Gel

A temperature-sensitive hair dye was prepared with a poloxamer-sodium alginate mixture. When the hair dye was applied to the hair (< 32 °C), it retained its flow dynamics. The hair dye was able to undergo a phase change and formed a solid as soon as it touched the scalp (32°C), which reduced the transdermal amount of p-phenylenediamine (PPD) and also adverse effects and toxicity. Compared to a conventional hair dye, the temperature-sensitive hair dye achieved a reduction of the transdermal amount of p-phenylenediamine by almost 65% at different concentrations. At the same time, the colouring effect was not significantly reduced. The poloxamer alginate hydrogel can be used as a novel colouring material to reduce the harm of the dye intermediate to the human body when colouring hair.