Monday, March 21, 2022SCCS

Sodium Bromothymol Blue: request for Opinion to the SCCS

Sodium bromothymol blue : demande d'Opinion au CSSC

The European Commission has asked the SCCS to assess the safety of Sodium Bromothymol Blue (a hair dye ingredient). The Scientific Committee accepted this mandate at its plenary meeting on 16 March 2022 and has nine months to deliver its Opinion.

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The ingredient with the INCI name “Sodium Bromothymol Blue” and chemical name “Sodium α-(3-bromo-5-isopropyl-4-oxo-2-methyl-2,5-cyclohexadienylidene)-2-(3-bromo-4-hydroxy-5-isopropyl-2-methylphenyl)toluenesulphonate” (CAS No.34722-90-2, EC No.252-169-7) is a weak acid in solution and thus exists in ionized and non-ionized forms that result in the appearance of different colours. Sodium Bromothymol Blue is intended to be used as a hair dye in non-oxidative hair colouring products with a final on-head concentration up to 0.5%.

In order to demonstrate the safety of Sodium Bromothymol Blue, this dossier submission is established on a battery of non-animal methods and approaches, including in silico and in vitro methods, assessing inter alia irritation, skin sensitization, genetic toxicity and percutaneous absorption, while following Good Laboratory Practice and OECD guidelines. In particular, notwithstanding the absence of data on repeated dose or reproductive/developmental toxicity, the submitters have used the Toxicological Threshold of Concern (TTC) approach to support the safe use of this ingredient based on the very low consumer exposure estimate.

Questions to SCCS

1. In light of the data provided, does the SCCS consider Sodium Bromothymol Blue, safe when used in non-oxidative hair colouring products up to a maximum on-head concentration of 0.5 %?

2. Does the SCCS have any further scientific concerns with regard …

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