Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

There are no data available on skin sensitisation for sodium methylparaben. However, there are reliable data on the structurally related substance methylparaben.Based on a weight of evidence approach using data from methylparaben and a QSAR calculation on the target substance itself, sodium methylparaben is considered to be not skin sensitising.

Three in vivo studies are available addressing skin sensitising properties of methylparaben.

Methylparaben was investigated in a Maurer Optimization Test equivalent to OECD 406 (Maurer, 1980). 20 guinea pigs (10 male/10 female) received an injection of 0.1% methylparaben on every second day for 3 weeks. After 3 further weeks, the intradermal challenge was conducted, using 0.1% methylparaben. After 24 h, 3/20 animals of the test substance group and no animals of the negative control showed positive reactions. All positive control animals (treated with 0.1% cinnamic aldehyde) showed positive reactions. For the epidermal challenge 2 weeks later, 5% methylparaben were applied. After 24 h, positive reactions were noted in 4/20 animals of the test substance group and no animals of the negative control. The positive control animals were treated with 3% cinnamic aldehyde. After 24 h, 19/20 animals showed positive reactions.

Under the test conditions, the test substance was not considered to be a skin sensitiser.

 

In a further study, performed similar to the Maurer Optimization test and OECD 406, male guinea pigs were treated 3 times a week with an injection of 0.1% methylparaben in physiological saline for induction (Sokol, 1952). Two weeks after the last injection, the guinea pigs got a challenge injection with 0.1% methylparaben in physiological saline. The readings at 24 and 48 h after the challenge revealed no allergic response in any animal.

 

In another study, methylparaben was examined in 10 guinea pigs in a Buehler test according to OECD 406 (Anon., 1981). The test item was a hairdressing formulation with a methylparaben concentration of 0.2%. For induction, applications on the shaved back of the animals were made 3 times per week for a total of 3 weeks. During the induction phase, a slight irritation was observed. Two weeks after the last induction application, the animals received a challenge application. At the reading time points, 2 and 24 h after patch removal, no positive reactions in any animal were observed. 

 

There are no further animal or human data available on the skin sensitising potential of methylparaben.

By calculating the likelihood of interactions of sodium methylparaben with skin proteins, no structural alerts were found (DR. KNOELL CONSULT, 2012). Therefore, no interactions of sodium methylparaben with skin proteins are expected.

Furthermore, there is no evidence of chemically reactive properties of sodium methylparaben under in vitro test conditions. This is confirmed by studies on genetic toxicity in vitro (Ames test, gene mutation in mammalian cells in vitro) which were all negative.


Migrated from Short description of key information:
Skin sensitization: not sensitizing

Justification for selection of skin sensitisation endpoint:
Hazard assessment is based on the weight of evidence from all available studies and a QSAR calculation.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

The available data on skin sensitisation of the test substance does not meet the criteria for classification according to Regulation (EC) 1272/2008 or Directive 67/548/EEC, and is therefore conclusive but not sufficient for classification.