6,6'-di-tert-butyl-2,2'-methylenedi-p-cresol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Remarks:

in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

yes

Remarks:

modification refer to measurement of cell proliferation by cell counting instead of radioactive labeling; in addition the acute inflammatory skin reaction is determined to discriminate specific from non-specific activation of immune competent cells in the

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

Remarks:

modification refer to measurement of cell proliferation by cell counting instead of radioactive labeling; in addition the acute inflammatory skin reaction is determined to discriminate specific from non-specific activation of immune competent in the drai

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

6,6'-di-tert-butyl-2,2'-methylenedi-p-cresol

EC Number:

204-327-1

EC Name:

6,6'-di-tert-butyl-2,2'-methylenedi-p-cresol

Cas Number:

119-47-1

Molecular formula:

C23H32O2

IUPAC Name:

2-tert-butyl-6-[(3-tert-butyl-2-hydroxy-5-methylphenyl)methyl]-4-methylphenol

Details on test material:

6,6’-di-tert-butyl-2,2’-methylendi-p-cresol (Vulkanox BKF), purity: 97 to 98%

In vivo test system

Test animals

Species:

mouse

Strain:

NMRI

Sex:

female

Study design: in vivo (LLNA)

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

0, 2%, 10% 50%

No. of animals per dose:

6 per dose group

Results and discussion

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: neither a non-specific (irritant nor a specific immunostimulating (sensitzing) potential of the test item was revealed; cell count index: vehicle control: 1.00, 2%: 1.17, 10%: 1.16, 50%: 1.22

Results 2

Parameter:

SI

Remarks:

Cell count index

Value:

1

Test group / Remarks:

Group 1

Remarks on result:

other:

Remarks:

Dose (%) = 0

Results 3

Parameter:

SI

Remarks:

Cell count index

Value:

1.17

Test group / Remarks:

Group 2

Remarks on result:

other:

Remarks:

Dose (%) = 2

Results 4

Parameter:

SI

Remarks:

Cell count index

Value:

1.16

Test group / Remarks:

Group 3

Remarks on result:

other:

Remarks:

Dose (%) = 10

Results 5

Parameter:

SI

Remarks:

Cell count index

Value:

1.22

Test group / Remarks:

Group 4

Remarks on result:

other:

Remarks:

Dose (%) = 50

Any other information on results incl. tables

Groups of female NMRI mice were treated with vehicle, 2%, 10% or 50% test substance in AOO.

The NMRI mice treated with the test substance 6,6’-di-tert-butyl-2,2’-methylendi-p-cresol did not show an increase in the stimulation indices for cell counts or for weights of the draining lymph nodes. The "positive level" which is 1.4 for the cell count index was not reached or exceeded in any dose group (cell count index: 1.0, 1.17, 1.16, 1.22 at 0, 2%, 10% or 50% test substance solution, respectively). The “positive level” of ear swelling, which is 2x 10-2 mm increase, i.e. about 10% of the control values, was not reached or exceeded in any treatment group. In addition, no substance specific effects were determined for ear weights.

no treatment-related effcts on body weights were noted.

Based on the findings of this study, the author suggested that neither a non-specific (irritant) nor a specific immune stimulating (sensitizing) potential of the test substance was indicated.

Table: Direct LLNA (NMRI mice, 6 animals/group) lymph node weight index and cell count index (index mean ± SD in %)

Dose (%)	Weight index (index mean ± SD in %)	Cell count index (index of mean ± in %)
0	1.00 ± 13.89	1.00 ±16 .46
2	1.11 ± 16.92	1.17 ± 17.57
10	1.09 ± 11.56	1.16 ± 13.12
50	1.08 ± 14.16	1.22 ± 8.07

Table: Ear swelling (NMRI mice, female, 6 animals/group, in 0.01 mm)

Dose (%)	day 1 (mean ± SD in %)	day 4 (mean ± SD in %)	Index day 4
0	17.42 ± 2.96	17.67 ± 2.79	1.00
2	17.25 ± 2.62	18.42 ± 4.89	1.04
10	17.58 ± 3.80	18.58 ± 8.10	1.05
50	17.67 ± 2.79	18.33 ± 3.55	1.04

Table Ear weight (NMRI mice, female, 6 animals/group, in mg per 8 mm diameter punch)

Dose (%)	day 4 (mean ± SD in %)	Index day 4
0	12.20 ± 7.11	1.00
2	12.83 ± 8.30	1.05
10	12.90 ± 7.62	1.06
50	12.63 ± 9.88	1.04

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met