Sulfuric acid, C12-14 (even numbered)-alkyl esters, (2-hydroxylpropyl)ammonium salts

Endpoint summary

Description of key information

skin sensitization (OECD 406): not sensitizing

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

There is no study regarding sensitisation available for C12-14 AS MIPA (CAS 85681-66-9). Therefore this endpoint is covered by read across to structurally related alkyl sulfates (AS) for weight-of-evidence approach, i.e. C12-14 AS NH4 (CAS 90989-98-3) and C12-14 AS Na (CAS 85586-07-8). The possibility of a read-across to other alkyl sulfates in accordance with Regulation (EC) No 1907/2006 Annex XI 1.5 “Grouping of substances and read-across approach” was assessed. In Annex XI 1.5 it is given that a read-across approach is possible for substances whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity. The AS reported within the AS category show structural similarity. The most important common structural feature of the category members is the presence of a predominantly linear aliphatic hydrocarbon chain with a polar sulfate group, neutralized with a counter ion. This structural feature confers the surfactant properties of the alkyl sulfates. The surfactant property of the members of the AS category in turn represent the predominant attribute in mediating effects on mammalian health. Therefore, the AS of the AS category have similar physicochemical, environmental and toxicological properties, validating the read across approach within the category. The approach of grouping different AS for the evaluation of their effects on human health and the environment was also made by the OECD in the SIDS initial assessment profile [1] and by a voluntary industry program carrying out Human and Environmental Risk Assessments (HERA [2]), further supporting the read-across approach between structurally related AS.

 

Sensitisation

There is one study regarding skin sensitisation with C12-14 AS NH4 (CAS 90989-98-3) and a second study with C12-14 AS Na (CAS 85586-07-8) available.

The skin sensitizing potential of C12-14 AS NH4 (CAS 90989-98-3) was assessed in a Buehler test similar to OECD Guideline 406 in 10 guinea pigs (Stepan, 1991). Only limited data on the test item is available. Guinea pigs were topically induced 9 times over a period of 3 weeks with 0.1 % test substance and challenged with 0.1% test substance 2 weeks thereafter. 48 h after the first challenge a second challenge was performed with 0.1 % test item. Skin reactions were scored 24 and 48 h after challenge. The challenge and induction concentration was based on a preliminary range-finding study. No skin reactions were observed upon challenge. Thus the test item showed no significant sensitising potential within this study.

In a second study, the skin sensitizing potential of C12-14 AS Na (CAS 85586-07-8, analytical purity 29.9%) was assessed in a Guinea Pig Maximisation Test not following a guideline (Unilever, 1977a). In this study 10 guinea pigs were induced by intradermal and occlusive epicutaneous application of the test item at concentrations of 0.08% (intradermal induction) and 0.5% (epicutaneous induction). Challenge and re-challenge was performed with 0.1%. Water was used as vehicle. None of the treated animals showed a positive reaction after challenge. Thus, the test item showed no significant sensitising potential within this study.

Based on the above mentioned results, the data of the read-across substance C12-14 AS NH4 (CAS 90989-98-3) and C12-14 AS Na (CAS 85586-07-8) indicates no skin sensitisation potential. Therefore, C12-14 AS MIPA (CAS 85681-66-9) is not expected to be a skin sensitiser. Moreover, alkyl sulfate, i.e. sodium lauryl sulfate (C12 AS Na) is recommended as an agent to induce local irritation in a method to assess skin sensitising properties of chemicals (OECD guideline 406, Guinea Pig Maximisation Test). Hence, there is a lot of experience with sodium lauryl sulfate in sensitising studies and no evidence occurred that it shows sensitising properties. Thus, skin sensitisation by members of the alkyl sulfates is generally unlikely.

 

Influence of counter-ions on sensitizing potential

The effects on health of isopropanolamine (MIPA) are dominated by its corrosive properties. MIPA is listed in Annex VI of EG 1272/2008 as Skin Corrosive Category 1B, H314. Further information indicates MIPA to be moderately toxic after dermal application. During the registration process for 2010 MIPA was also classified as harmful in contact with skin (Acute Toxicity Cat 4, H312 according to Regulation 1272/2008/EC). There is no indication of skin sensitizing properties of MIPA. Therefore, contribution of MIPA to the endpoint sensitization is negligible.

 

[1] SIDS initial assessment profile, (2007); http://www.aciscience.org/docs/Alkyl_Sulfates_Final_SIAP.pdf

[2] (HERA Draft report, 2002); http://www.heraproject.com/files/3-HH-04-%20HERA%20AS%20HH%20web%20wd.pdf

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The available data on skin sensitisation do not meet the criteria for classification according to Regulation (EC) 1272/2008, and are therefore conclusive but not sufficient for classification.

No data available for respiratory sensitisation.