3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Accorduing to OECD Guideline and GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol

EC Number:

233-466-0

EC Name:

3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol

Cas Number:

10191-41-0

Molecular formula:

C29H50O2

IUPAC Name:

2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-3,4-dihydro-2H-1-benzopyran-6-ol

Details on test material:

- name: dl-alpha-tocopherol
- source: Research Institute for Fragrance Materials (see below)
- colour: clear
- conforming to USP requirements
- physical state: liquid
- CTL test substance reference number: Y11914/001 - 005
- expiry date: 2 May 2001
- storage conditions: ambient temperature (under inert gas)

Original source of RIFM test material: BASF SE
- Assay, USP: 96.0 - 102.0%
- appearance: yellow to amber viscous oil with sligt mild colour
- heavy metals: not more than 40 ppm
- lead: not more than 10 ppm
- organic volatile impurities: meets the requirements
- product number: 825962
- product name: vitamin E USP (dl-alpha)
- product code: BSF-54729958
- lot number: 35-4432

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Interfauna UK Limited, Blackthrone, Bicester Oxon, UK
- Age at study initiation: young adults
- Housing: 4 males per cage
- Diet (e.g. ad libitum): RM1, Special Diets Services Limitied, Witham essex, UK
- Water (e.g. ad libitum): tap water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3 °C
- air changes: min. 15 per hour
- Humidity (%): 30-70%
- Photoperiod (hrs dark / hrs light): 12 h/ 12 h

Study design: in vivo (LLNA)

Vehicle:

other: 3:1 EtOH:DEP (test substance) and acetone (positive control).

Concentration:

0.3%; 1%; 3%; 10%; 30%.

No. of animals per dose:

4

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

The results are expressed as a counts per minute (cpm) value per lymph node for each group. The activity of each test group is then divided by the activity of the vehicle control group to give a test:control ratio for each concentration. The criterion for a positive response is that one or more concentrations of the test substance should elicit a 3-fold or greater increase in isotope incorporation relative to the vehicle control group. Consequently, a test substance which does not fulfil the above criterion is designated as unlikely to be a sensitiser.

EC3 calculations
The estimated concentration of the test substance required to produce a 3-fold increase in the draining lymph node cell proliferative activity (EC3) was calculated. The EC3 value was derived by interpolating between two points on the Sensitisation Index (SI) axis, one immediately above and the other immediately below the SI value of 3 (vehicle treated control values [SI= l] not being used for the latter). Where the data points lying immediately above and below the SI value ofthree have the co-ordinates (a,b) and (c,d) respectively, the EC3 value was calculated using the fo llowing equation:

EC3 = c + [(3-d)/(b-d)] x (a-c)

Results and discussion

Positive control results:

A concentrations used in the positive control experiments yielded an at least 3-fold increase in isotope incorporation and thus were valid.

In vivo (LLNA)

Results

Key result

Parameter:

EC3

Value:

> 3 - < 10

Any other information on results incl. tables

Skin sensitization potential of dl-alpha-tocopherol:

Concentration of test substance (% w/v)	Number of lymph nodes assayed	Counts per minute (cpm)	cpm per lymph node (x10 exp-2)	Test control ratio
0 (vehicle only)	8	2058	2.57	N/A
0.3	8	1260	1.58	0.61
1	8	1729	2.16	0.84
3	8	2257	2.82	1.1
10	8	8553	10.69	4.16
30	8	13843	17.3	6.73
N/A - not applicable

Skin sensitization potential of the positive control substance (hexylcinnamaldehyde):

Concentration of test substance (% w/v)	Number of lymph nodes assayed	Counts per minute (cpm)	cpm per lymph node (x10 exp-2)	Test control ratio
0 (vehicle only)	8	876	1.1	N/A
1	8	2755	3.44	3.13
3	8	4809	6.01	5.46
10	8	8160	10.2	9.27
N/A - not applicable

Applicant's summary and conclusion

Interpretation of results:

sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Based on the results of this study, D,L-alpha-tocopherol needs to be classified as Skin Sens 1B, according 1272/2008/EEC.