2,4,6-tri-sec-butylphenol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vitro

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 442C (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA))

Version / remarks:

OECD Guidelines for Testing of Chemicals, number 442c “In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA)” (adopted: February 04, 2015)

GLP compliance:

yes (incl. QA statement)

Type of study:

direct peptide reactivity assay (DPRA)

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6-tri-sec-butylphenol

EC Number:

227-572-6

EC Name:

2,4,6-tri-sec-butylphenol

Cas Number:

5892-47-7

Molecular formula:

C18H30O

IUPAC Name:

2,4,6-tris(butan-2-yl)phenol

Test material form:

liquid

Details on test material:

Name: 2,4,6-Tri-sec-butylphenol
Batch No.: DEG4425937
CAS No 5892-47-7
Molecular Weight: 262 g/mol
Purity: 94.4%
Physical State: liquid
Colour: light brown
Density: 0.911 g/cm3
Storage Conditions: room temperature, light protection
Expiry Date: 27 September 2019
Safety Precautions: The routine hygienic procedures were sufficient to assure personnel health and safety.

In vitro test system

Details on the study design:

Preparation of test item solution: the test item was dissolved in acetonitrile and a stock solution of 100 mM was prepared, whereby the purity of the registration substance in the test item was taken in account.
Incubation of test item with peptide solution: The test item solution were incubated with the cystein and lysine peptide solutions in glass vials using defined ratios of test item to peptide (10 cyctein peptide, 60 lysine peptide). The reaction solutions were lefr in the dark at 25 ± 2 hours before running the HPLC analysis. Reference controls, co-elution controls as well as the cynnamic aldehyde as positive control were set up in parallel.

Results and discussion

Positive control results:

The mean percent peptide depletion value of the three replicates for the positive control (cinnamic aldehyde) was between 60.8% and 100% for the cysteine peptide.
The mean percent peptide depletion value of the three replicates for the positive control (cinnamic aldehyde) was between 40.2% and 69.0% for the lysine peptide.

In vitro / in chemico

Results

Results 1

Key result

Parameter:

other: percentage cyctein peptide depletion

Remarks:

mean of three replicates

Value:

0

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Results 2

Key result

Parameter:

other: percentage lysine peptide depletion

Remarks:

mean of three replicates

Value:

0

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Any other information on results incl. tables

Results of the Cysteine Peptide Depletion
Sample	Peak Area at 220 nm	Peptide Concentration [mM]	Peptide Depletion [%]	Mean Peptide Depletion [%]	SD of Peptide Depletion [%]	CV of Peptide Depletion [%]
Positive Control	1320.4471	0.1577	70.95	71.10	0.18	0.25
	1315.4908	0.1571	71.06
	1304.7782	0.1559	71.29
Test Item	4599.0210	0.5435	0.00	0.00	0.00	-
	4764.8755	0.5631	0.00
	4555.8262	0.5385	0.00

Results of the Lysine Peptide Depletion
Sample	Peak Area at 220 nm	Peptide Concentration [mM]	Peptide Depletion [%]	Mean Peptide Depletion [%]	SD of Peptide Depletion [%]	CV of Peptide Depletion [%]
Positive Control	1660.4912	0.2034	59.71	60.33	0.55	0.92
	1627.6788	0.1994	60.51
	1616.5613	0.1980	60.78
Test Item	4253.7705	0.5204	0.00	0.00	0.00	-
	4218.3535	0.5161	0.00
	4216.4116	0.5158	0.00

Applicant's summary and conclusion

Interpretation of results:

other: The obtained results in this study alone cannot be used for the classification

Conclusions:

The skin sensitization property of the registration substance was investigated using the Direct Pepride Reactivity Assay (DPRA) according to the Guideline 442c. A negative result was obtained. No significant binding affinity to the cysteine or lysine of the peptide was found, indicating no acitivation of one of the key events in the adverse outcome pathway.

Executive summary:

The skin sensitization property of the registration substance was investigated using the Direct Pepride Reactivity Assay (DPRA) according to the Guideline 442c. A negative result was obtained. No significant binding affinity to the cysteine or lysine of the peptide was found, indicating no acitivation of one of the key events in the adverse outcome pathway.