In-situ hair coloration-chromophore development from selected aromatic amines – A high throughput delivery perspective

• Color performance of 2-methoxymethyl-p-phenylenediamine is compared to the one achieved with p-toluenediamine.
• This work has provided information relating to a viable gamut of achievable shades.
• The high throughput tool has enabled one to base decisions on data.

Key primary dye intermediates used in oxidative hair coloration for many decades, such as p-phenylenediamine or p-toluenediamine are under scrutiny because of their potential association with allergic contact dermatitis. Despite intensive research, no superior primary dye intermediate with equal coloration performance and reduced skin sensitization properties has emerged up until today. A primary intermediate, 2-methoxymethyl-p-phenylenediamine, a molecule that produces excellent hair coloring performance and the benefits of the reduced risk of allergy induction is presented. The actual precise color generation performance of 2-methoxymethyl-p-phenylenediamine has been compared with that of one of the more commonly used primary dye intermediate in hair coloration, p-toluenediamine. This work was carried out using a high throughput delivery tool in formulation because the hair colorant formulations are commonly composed of over 15 ingredients, being formulated in specific sequences (involving heating/cooling, order of addition and stirring) that can be time consuming.