Sorbitan monolaurate, ethoxylated

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Sensitisation

A skin sensitization study was performed according to OECD 429 (Notox 2012) with sorbitan monolaurate, ethoxylated (<2.5 EO, Polysorbate 21, CAS 9005-64-5). 25, 50 and 100% of the test substance dissolved in acetone/olive oil (4:1, v/v) were applied in a total dose of 25 µl to each ear of 5 female CBA mice each on three consecutive days. On day 6 of the experiment, 3H-methyl thymidine (3H-TdR) was injected into the tail vein of each experimental mouse to assess the proliferative response. Approximately five hours later, all animals were killed and the draining auricular lymph node of each ear was excised into PBS and a single cell suspension was prepared which was precipitated with trichloroacetic acid in preparation for scintillation. The mean DPM/animal value determined for the vehicle control group was 537 DPM. For the experimental groups treated with test substance concentrations of 25, 50 and 100%, values of 1040, 3210 and 2700 DPM, respectively, were found revealing SI values of 1.9, 6.0 and 5.0. The data showed a dose-response, except the 100% dose group did not follow the expected dose-response relationship which is often seen in these kind of studies. The response might be less due to differences in skin penetration (no vehicle present) or viscosity or due to underlying systemic toxicity. An EC3 value of 34% was calculated. A reliability test with an appropriate positive control was performed and revealed the expected results. Under the conditions of this test, the test substance was considered to be a skin sensitizer. Although the LLNA is the recommended test system for skin sensitisation under REACh, it is known that the LLNA can lead to an overpredicted sensitisation potential for surfactants (Ball et al. 2011). Therefore, as the test substance represents a surfactant, a guinea pig maximisation test according to Magnusson and Kligman was conducted additionally (Notox 2012). The study was performed similar to OECD 406 under GLP conditions with the following concentrations of the test substance dissolved in corn oil: 2% for intradermal induction, 100% for epidermal indcution and challenge. At challenge, the test substance at 100% induced no effects in test and control group animals. The positive control (20% alpha hexyl cinnamic acid) induced the expected results. Thus, under the conditions of this test, the test substance was not a skin sensitiser. Taken all these data into consideration, it seems reasonable to interpret the positive result of the LLNA as a false positive result. In addition to the animal data, the test substance was also tested in a human patch test (Schwartz 1959). 50 subjects were exposed to the undiluted test substance under occlusive conditions initially for 3 days and in a challenge 7 days after removal of the initial patch. At the end of the 72 h exposure period in the challenging application, no reactions on the skin of any of the subjects were observed. Taking all data into consideration, it is concluded that the test substance is not a skin sensitizer.

Reference: Ball N, Cagen S, Carrillo JC, Certa H, Eigler D, Emter R, Faulhammer F, Garcia C, Graham C, Haux C, Kolle SN, Kreiling R, Natsch A, Mehling A (2011): Evaluating the sensitization potential of surfactants: integrating data from the local lymph node assay, guinea pig maximisation test, and in vitro methods in a weight-of-evidence approach.

Migrated from Short description of key information:
Skin sensitisation (GPMT): not sensitising
Skin sensitisation (LLNA): sensitising

Justification for selection of skin sensitisation endpoint:
The selected study is the most adequate and reliable study.

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 do not meet the criteria for classification according to Regulation (EC) 1272/2008 or Directive 67/548/EEC, and are therefore conclusive but not sufficient for classification.