Santalene oil: fermentation products of glucose with santalene synthase modified Rhodobacter sphaeroides, distilled

Endpoint summary

Description of key information

Skin: OECD TG 439, EpiDerm (TM) in vitro Skin Irritation Test (30 µL single exposure (undiluted)): non-irritant (BASF 2020; 68V0058/20A007)

Eye: OECD TG 492, EpiOcular(TM) in vitro Eye Irritation Test (50 µL single exposure (undiluted)): non-irritant (BASF 2020; 68V0058/20A008)

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation

In the key study for skin irritation (in accordance with TG OECD 439), 3 human reconstituted epidermis tissues (EpiDerm™) were treated with 30 µL undiluted Santalene Oil for 1 hour followed by a 42-hour post-incubation period, and a subsequent cell viability (MTT) test (BASF 2020; 68V0058/20A007). In addition to the test substance, control tissues were applied concurrently with 30 µL sterile PBS as negative control or with 30 µL 5% SDS as positive control to 3 tissues each. The optical density of the extracts of the tissues treated with the test substance was compared to negative control values from tissues treated with PBS, expressed as relative tissue viability. Based on the result of a pretest, the test substance is able to reduce MTT directly. Therefore, additional MTT reduction controls (freeze-killed control tissues) were applied concurrently with 30 µL sterile PBS or undiluted test substance (3 tissues each). However, the results of the killed control tissues did not indicate an increased MTT reduction.

Incubation of the reconstituted tissues with Santalene Oil resulted in a mean viability of 97.3% (+/- 4.9% SD) compared to respective control tissue viabilities. Treatment with the positive control resulted in a mean viability of 2.1% (+/- 0.2% SD) compared to respective control tissue viabilities.

Based on the results observed and by applying the evaluation criteria described, it was concluded that Santalene Oil does not show a skin irritation potential in the EpiDerm™ in vitro skin irritation test under the test conditions chosen.

 

Eye irritation

In the key study for eye irritation (in accordance with TG OECD 492), 2 EpiOcular™ tissues were treated with 50 µL undiluted Santalene Oil, covering the whole tissue surface for 30 minutes followed by a 2-hour post-incubation period, and a subsequent cell viability (MTT) test (BASF 2020; 68V0058/20A008). In addition to the test substance, control tissues were applied concurrently with 50 µL sterile deionized water as negative control or with 50 µL methyl acetate as positive control to 2 tissues each. The optical density of the extracts of the tissues treated with the test substance was compared to negative control values, expressed as relative tissue viability. Based on the result of a pretest, the test substance is able to reduce MTT directly. Thus, two freeze-killed control tissues were treated additionally with each the test item and the negative control in the same way as the viable tissues. The results of the freeze-killed control tissues indicate an increased MTT reduction (relative mean tissue viability 0.1 % of the negative controls). Thus, the final mean viability values for test substance treated tissues were corrected accordingly.

Incubation of the reconstituted tissues with the test substance resulted in a mean viability of 100.6% (+/- 4.3% inter-tissue variability) compared to respective control tissue viabilities. Treatment with the positive control resulted in a mean viability of 20.7% (+/- 7.0% inter-tissue variability) compared to respective control tissue viabilities.

Based on the results observed in the EpiOcular™ test alone and by applying the evaluation criteria, it was concluded that Santalene Oil does not show an eye irritation potential in the in vitro eye irritation test strategy under the test conditions chosen. Using the currently available in vitro methods, a single in vitro assay is not sufficient to cover the full range of an eye-irritating potential. Therefore, two in vitro assays were part of this in vitro eye irritation test strategy: The Bovine Corneal Opacity and the Permeability Test (BCOP Test) and EpiOcular™ Eye Irritation Test (EIT). In case of the data obtained for Santalene Oil, the results derived with EpiOcular™ test alone were sufficient for a final assessment. Therefore, further testing in a BCOP test was waived.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. According to these data the criteria for a classification as skin or eye irritant under Regulation (EC) No. 1272/2008 are not met.