Fatty acids, coco, 2-sulfoethyl esters, sodium salts

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study in accordance with EU Method B.6 and OECD TG 406

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

Type of study:

Buehler test

Justification for non-LLNA method:

Reliable and adequate studies using non-LLNA methods were already available.

Species:

guinea pig

Strain:

Pirbright-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Hoechst AG, Kastengrund, SPF-Zucht
- Age at study initiation: not reported
- Weight at study initiation: mean of thirty animals was 364 g (316 - 403 g)
- Housing: climated rooms; groups of five animals were kept in Makrolon cages (Type 4) with soft wooden bedding
- Diet (e.g. ad libitum): Altromin 3112 diet for guinea pigs, Altromin GmbH, Lage/Lippe
- Water (e.g. ad libitum): tap water from plastic bottles
- Acclimation period: at least 1 day (due to identical conditions in the breeding facility, a period of 5 days was not required)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 3
- Humidity (%): 50 ± 20
- Air changes (per hr): not reported
- Photoperiod (hrs dark / hrs light): 12 dark/12 hours light

Route:

epicutaneous, occlusive

Vehicle:

water

Remarks:

deionised

Concentration / amount:

To determine the skin-irritating concentration, 100%, 50% and 25% substance mixed with deionised water was used. An amount of 0.5 g of the solid substance was mixed with 0.3 mL deionised water in the final tests.

Route:

epicutaneous, occlusive

Vehicle:

water

Remarks:

deionised

Concentration / amount:

To determine the skin-irritating concentration, 100%, 50% and 25% substance mixed with deionised water was used. An amount of 0.5 g of the solid substance was mixed with 0.3 mL deionised water in the final tests.

No. of animals per dose:

Pre-test for skin-irritating concentration: 6 animals
Test group: 20 animals
Solvent control: 10 animals

Details on study design:

RANGE FINDING TESTS:
Six animals were used in the pre-test to find the skin irritating concentration. Two animals each were treated with 100%, 50% or 25% of the substance mixed with water. The mixture was spread onto patches (2 x 2 cm), which were fixed with occlusive tape on the shaved left flanks of animals. Patches were removed after six hours, treated skin was gently rinsed with water and skin irritation was evaluated 24 hours after patch removal.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: animals in the test group were exposed epicutaneously three times
- Exposure period: patches were fixed on the shaved flanks of animals with occlusive tape and left in place for six hours
- Test groups: 20 animals were treated in the test group
- Control group: 10 animals in the control group were treated with deionised water in a similar manner as test animals
- Site: substance and vehicle were applied to the shaved left flanks of animals
- Frequency of applications: application occurred at intervals of 7 days
- Duration: 6 hours
- Concentrations: 0.5 g of neat substance mixed with 0.3 mL of deionised water

B. CHALLENGE EXPOSURE
- No. of exposures: one epicutaneous exposure
- Day(s) of challenge: 28 days after first dermal induction exposure
- Exposure period: 6 hours
- Test groups: 20 animals were treated in the test group
- Control group: 10 animals were treated similarly in the control group
- Site: untreated skin area on the back right flank, which was shaved prior to treatment
- Concentrations: 0.5 g of neat substance mixed with 0.3 mL of deionised water
- Evaluation (hr after challenge): 24 hours and 48 hours after patch removal

Positive control substance(s):

no

Positive control results:

not applicable

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

0.5 g test substance in 0.3 mL water

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

no abnormal reactions reported

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 0.5 g test substance in 0.3 mL water. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no abnormal reactions reported.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

0.5 g test substance in 0.3 mL water

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

no abnormal reactions reported

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 0.5 g test substance in 0.3 mL water. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no abnormal reactions reported.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0.5 g test substance in 0.3 mL water

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no abnormal reactions reported

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 0.5 g test substance in 0.3 mL water. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no abnormal reactions reported.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0.5 g test substance in 0.3 mL water

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no abnormal reactions reported

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 0.5 g test substance in 0.3 mL water. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no abnormal reactions reported.

The development of the body weight was similar in the control and the test group.

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The substance was non-sensitising to the skin of guinea pigs in a Buehler test when applied as neat substance mixed with a small volume of deionised water.

Executive summary:

The skin sensitising potential of the test item was studied under GLP in female Pirbright-White guinea pigs in a valid Buehler test according to OECD TG 406. The non-irritating concentration of the substance was determined in a pre-test using six animals. Substance mixed with deionised water was applied under occlusion to the shaved skin of the left flanks of two animals each in concentrations of 100%, 50% and 25% for 6 hours. Skin reactions were scored 24 hours after patch removal. None of the concentrations was irritating to the skin. The study was conducted with a test group of 20 animals and a control group of 10 animals. An amount of 0.5 g of the solid test substance was mixed with 0.3 mL of deionised water and spread on cellulose patches (2 x 2 cm), which were then topically applied under occlusion to the shaved skin on the left flanks of test animals for six hours. Patches were then removed and the application area was gently rinsed with lukewarm water. Skin reactions were noted. The dermal induction procedure was repeated three times on days 1, 8 and 15. Control animals were treated in a similar way using deionised water only. The challenge exposure occurred on day 29: all animals from the test group and control group were exposed topically to an amount of 0.5 g of the solid substance mixed with 0.3 mL of deionised water. Patches were applied topically under occlusion to the shaved skin of the back right flank of all animals for 6 hours. None of the animals in the test group and the control group showed any skin reaction 24 hours or 48 hours after patch removal or adverse signs of intoxication. It was concluded that the substance was non-sensitising to the skin of guinea pigs under the conditions of the Buehler test.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

There are four guinea pig skin sensitization studies available for coco fatty acids 2-sulphoethyl ester sodium salt. Two were performed using the Buehler test and two using the Magnusson and Kligman test. The Buehler study performed in 1985 is not considered suitable for use in classification because it is classed as Klimisch 3 as only a 2% of cocoa fatty acids 2-sulphoethyl ester sodium salt was used for the induction and challenge doses. Therefore the results of the key Buehler study performed in 1994 and the two supporting Magnusson and Kligman studies performed in 1978 and 1983 will be discussed in this section.

The key Klimisch 1 Buehler study was carried out according to the OECD guideline 406 under GLP conditions using 20 guinea pigs. No responses were observed in any of the guinea pigs despite the use of 100% of the Coco fatty acids 2-sulfoethyl ester, sodium salt for both the induction and challenge phases.

The two supporting Magnusson and Kligman studies are Klimisch 2 and were carried out according to the OECD guideline 406 under GLP conditions using 10 guinea pigs per study. Faint responses were observed in these studies, but it is felt the results were less reliable because only 10 animals were used in the Magnusson and Kligman studies compared to the 20 used in the Buehler study.

In the first of the Mangusson and Kligman studies (Unilever Skin Sensitisation SSM780397) performed in 1978, a 0.15% intradermal induction dose and a 2% epicutaneous induction dose was used followed by 5% Coco fatty acids 2-sulfoethyl ester, sodium salt in the challenge doses. Several challenge doses were used due to a low level of faint responses being observed in 1 or 2 animals, but no responses were seen at one re-challenge at both 24 and 48 hours.

In the second Magnusson and Kligman study (Unilever Skin Sensitisation SSM830078) performed in 1994 a 0.2% intradermal induction dose and a 2.5% epicutaneous induction dose was used followed by 1% Coco fatty acids 2-sulfoethyl ester, sodium salt in the challenge dose. Again in this study two additional challenge doses were applied and inconsistent observations of faint/very faint reactions were seen in one or two guinea pigs, with the exception of the first re-challenge dose where no responses were seen. Additionally in a genuine sensitization reaction it would be expected that an increase in reactions would be observed at 48 hours when compared to the 24 hour readings and this was not observed in this study.

It is concluded that based on the weight of evidence, there is no convincing evidence that any animals had been sensitized in the three studies, therefore Coco fatty acids 2-sulfoethyl ester, sodium salt is not a skin sensitizer in Guinea pigs.

Migrated from Short description of key information:

There are three valid guinea pig skin sensitization studies available for coco fatty acids 2-sulphoethyl ester sodium salt.  A Klimisch 1 Buehler study carried out according to the OECD guideline 406 under GLP conditions using 20 test and 10 control guinea pigs and two Klimisch 2, Magnusson and Kligman studies carried out according to the OECD guideline 406 under GLP conditions using 10 test and four control guinea pigs per study.  Faint responses were observed in the Magnusson and Kligman studies, but it was felt the results were less reliable because only 10 test animals were used in these studies compared to the 20 used in the Buehler study.  There was no clear evidence of potential for skin sensitization.

Justification for selection of skin sensitisation endpoint:

There are four guinea pig skin sensitization studies available for coco fatty acids 2-sulphoethyl ester sodium salt.  Two were performed using the Buehler test and two using the Magnusson and Kligman test.  The Buehler study performed in 1985 is not considered suitable for use in classification because it is classed as Klimisch 3 as only a 2% of cocoa fatty acids 2-sulphoethyl ester sodium salt was used for the induction and challenge doses.  The Klimisch 1 study Skin sensitization, Buehler Test 1994 Klimisch 1 has been selected as the key study.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Coco fatty acids 2-sulfoethyl ester, sodium saltwas not found to be a skin sensitiser when tested in three vaild OECD 406 studies, this indicates that it is unlikely to posses any significant potential for respiratory sensitisation. The physical form of Coco fatty acids 2-sulfoethyl ester, sodium salt as a solidwith a low vapour pressure means inhalation exposure will be minimal. Based on this information it is not considered to be likely to be a respiratory sensitiser.

Migrated from Short description of key information:

There is no standard validated animal test available to detect respiratory sensitisers.  However as a general rule all respiratory sensitisers are also skin sensitisers.  Therefore in the absence of human evidence of respiratory sensitization potential, skin sensitization data will be used to indicate the possibility of respiratory sensitisation.

Justification for selection of respiratory sensitisation endpoint:

There is no standard validated animal test available to detect respiratory sensitisers.

Justification for classification or non-classification

There are four guinea pig skin sensitization studies available for cocoa fatty acids 2-sulphoethyl ester sodium salt. Two were performed using the Buehler test and two using the Magnusson and Kligman test. The Buehler study performed in 1985 is not considered suitable for use in classification because it is classed as Klimisch 3 as only a 2% of cocoa fatty acids 2-sulphoethyl ester sodium salt was used for the induction and challenge doses.  While there were faint responses in the Magnusson and Kligman tests, these studies are less reliable due to the use of reduced animal numbers, 10 test animals rather than 20, and 4 rather than 10 negative controls. The Buehler study showed no evidence of any reactions despite the use of the 100%Coco fatty acids 2-sulfoethyl ester, sodium salt. Both the Magnusson and Kligman studies showed some inconsistent faint or very faint reactions in 1 or 2 out of 10 Guinea pigs, but no reactions on some challenges. As a general rule all respiratory sensitisers are also skin sensitisers. Therefore in the absence of human evidence of respiratory sensitization potential, skin sensitization data will be used to indicate the possibility.The weight of evidence is that Coco fatty acids 2-sulfoethyl ester, sodium salt is not a skin sensitizer and therefore not classified as either a skin or respiratory sensitiser.