SCCS Opinion on 2,5,6-Triamino-4-pyrimidinol sulfate (Colipa No. A143) and HC Yellow No. 17 (B121)

At its 10th plenary meeting, the Scientific Committee on Consumer Safety adopted opinions on both 2,5,6-Triamino-4-pyrimidinol sulfate (CAS 1603-02-7) and HC Yellow No.17, which are used as hair dyes in cosmetic formulations.

HC Yellow No. 17 is a new ingredient planned to be used in non-oxidative hair coloring products, whereas 2,5,6-Triamino-4-pyrimidinol sulphate is an oxidative hair coloring agent for which the SCCP already adopted an opinion in September 2008, concluding that:

the safe use of 2,5,6-triamìno-4-pyrìmìdìnol sulfate as an ingredient in oxidative hair dye formulations at a maximum concentration of 0.5% on the head cannot be assessed. The potential for induction of gene mutations has to be clarified. Furthermore, studies on genotoxicity/mutagenicity in finished hair dye formulations should be undertaken following the relevant SCCNFP/SCCP opinions and in accordance with its Notes of Guidance.

A skin sensitizing potential of 2,5,6-triamino-4-pyrimidinol sulfate cannot be excluded.


Evaluation of 2,5,6-Triamino-4-pyrimidinol sulphate

Recently, new scientific results from a HPRT essay for mammalian gene mutation were provided to SCCS in order to reassess the safety of the colorant. It was concluded that under the experimental conditions used in that gene mutation assay the colorant was not mutagenic. In the light of the new data provided 2,5,6-Triamino-4-pyrimidinol sulphate was considered to have no genotoxic potential. Consequently the colorant was considered safe when used as an ingredient in oxidative hair formulations at a maximum concentration of 0.5% on the head; however, its irritating potential could not be excluded.

Evaluation of HC Yellow No.17

Results obtained in the irritation and sensitization study of HC Yellow No. 17 revealed it does not cause severe ocular irritation, but its mild eye irritancy potential could not be excluded. On the other hand HC Yellow No. 17 was considered as a strong sensitizer capable of inducing delayed contact hypersensitivity. However, being a new hair day, its allergic potential in humans should be evaluated as well when exposure in consumers will occur. HC Yellow No. 17 was tested for its mutagenic potential as well. Under the conditions of the study, the colorant was considered not to be mutagenic. On the basis of the data provided the SCCS considered the hair dye safe when used in non-oxidative hair coloring products at concentrations of up to 0.5%, except for its sensitization potential.

Steps to take

When considering use of 2,5,6-Triamino-4-pyrimidinol sulphate or HC Yellow No.17 in hair coloring products manufacturers should make sure the concentrations of the two colorants do not exceed the allowed % concentration. Although both colorants were considered safe, sensitization potential of HC Yellow No. 17 should also be taken into account. The existing formulas should be revised as well. For further advice please approach your Responsible Person.

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