N-isopropylmethacrylamide

Repeated dose toxicity: dermal

Administrative data

Endpoint:

short-term repeated dose toxicity: dermal

Data waiving:

exposure considerations

Justification for data waiving:

a short-term toxicity study does not need to be conducted because exposure of humans via the dermal route in production and/or use is not likely as based on the provided thorough and rigorous exposure assessment

Justification for type of information:

In accordance with REACH Annex VIII 8.6.1 (short-term repeat dose toxicity), testing by the dermal route is appropriate if:
- inhalation of the substance is unlikely; and
- skin contact in production and/or use is likely; and
- the physicochemical and toxicological properties suggest potential for a significant rate of absorption through the skin.

A toxicokinetic assessment based on available study data on the substance showed evidence to support the absorption of the substance following oral administration (based on acute oral and OECD 422 studies). Although the log Pow value is low, the actual molecule size and water solubility of the test item suggest that absorption across the gastro-intestinal tract would be a result of a simple diffusion process and therefore provides a route of potential absorption, following oral administration.

Limited absorption may occur via the skin due to small molecular size and the solubility of the test item but no systemic effects were observed in an acute dermal toxicity study and the substance is not a skin sensitiser or irritant.

The substance is therefore considered to be more readily available via the oral route than dermal.

The substance is a monomer intermediate in the synthesis of polymers. During the synthesis of the polymers there is anticipated to be some potential dermal exposure to the substance to factory workers, quality assurance personnel and maintenance personnel. Appropriate PPE will therefore be worn be workers to reduce any potential dermal exposure.

The lifecycle of the monomer is considered to end when it is reacted into the polymer.

Based on the above information a repeated dose dermal toxicity study has not been conducted.

A route-to-route extrapolation for oral to dermal route has been performed to derive a DNEL for long-term effects for dermal exposure, based on the results of an oral OECD 422 study conducted on the substance.

Results and discussion

Target system / organ toxicity

Critical effects observed:

not specified