Bottom residues resulting from the synthesis of isoprene and isoamylene by dehydrogenation of isopentane

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

June to December 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: study performed according to OECD guideline and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

modified as IMDS test

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Absorbent N Grade A

IUPAC Name:

Absorbent N Grade A

Details on test material:

- Name of test material (as cited in study report): Absorbent N grade A
- Substance type: UVCB
- Physical state: Brown liquid
- Stability under test conditions: months
- Storage condition of test material: room temperature, in the dark

In vivo test system

Test animals

Species:

mouse

Strain:

NMRI

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: from the company Charles River Deutschland GmbH, D-97633 Sulzfeld
- Age at study initiation: 9-10 weeks
- Weight at study initiation: 29 to 37 g
- Housing: transparent macrolone cages (type 150, floor area 810 cm²) with 6 animals in each cages
- Diet: a pelleted complete rodent diet "Altromin 1324", ad libitum
- Water: free access to bottles of drinking water of domestic quality, which was acidified with hydrochloric acid to pH 2.5 in order to prevent microbial growth
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 21 +/- 3°C
- Humidity: at least 30% and preferably not exceed 70%
- Air changes: 10 per hr
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: the experimental phase was carried out between September 19th and 22nd 2011

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

25, 50 and 100% (v/v)

No. of animals per dose:

6 animals per dose

Details on study design:

RANGE FINDING TESTS: data not available

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA / IMDS
- Criteria used to consider a positive response:
A differentiation index (DI) is calculated from the different parameters of investigation which describes the relation between the activation of the local skin-draining lymph nodes and the skin inflammation at the site of topical treatment as well as it contributes to distinguish between inflammatory (non-specific) and allergic (specific) reaction:
- 0 < DI < 1 : inflammation
- DI > 1 : allergic reaction

DI = (% max. LN cell count index increase) / (% max. ear thickness increase)

TREATMENT PREPARATION AND ADMINISTRATION:
30 albino mice of the strain Crl:NMRI in groups consisting of six animals each were treated with three concentrations of the test item (100%, 50% and 25% v/v) or only with the vehicle acetone/olive oil (4/1 v/v) on three consecutive days. An amount of 25µL of the test substances was applied on the dorsal side of each ear.

Positive control substance(s):

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

Statistics:

data not available

Results and discussion

Positive control results:

The parallel tested positive control showed a differentiation index (DI) of 2.29

In vivo (LLNA)

Results

Parameter:

SI

Remarks on result:

other: Negative control: 1.00 Positive control: 1.60 Test item 100%: 1.90 Test Item 50%: 1.40 Test Item 25%: 1.25

Applicant's summary and conclusion

Interpretation of results:

sensitising

Remarks:

Migrated information

Conclusions:

Based on the result of the study described a specific (sensitizing) potential shall be attributed to the 100 % (v/v) test item.

Executive summary:

The test item was investigated for the existence of a specific (sensitizing) or non-specific (irritant) stimulation potential by using the modified Local Lymph Node Assay (IMDS).

Thirty albino mice of the strain Crl:NMRI in groups consisting of six animals each were treated with three concentrations of the test item (100%, 50% and 25% v/v), with a 30 % (active) solution of alpha Hexylcinnamelehde, technical grade, 85 % as positive control or only with the vehicle acetone/olive oil (4/1 v/v) as a negative control on three consecutive days. An amount of 25µL of the test substances was applied on the dorsal side of each ear. The determination of ear thickness, ear weight, lymph node weight and lymph node cell count compared to the negative control (vehicle group) should provide the information whether the test item has a specific (sensitizing) or non-specific (irritant) stimulation potential and should verify the suitability and reliability of the test method based on the data of the positive control.

A positive increase of the thickness of ears was recorded on day 4 neighter in the animals of the test groups nor in the animals of the positive control in comparison wih the negative control. The determination of the ear weights showed a well-defined increase only in the positive control and in the test group of the 100 % (v/v) test item compared to the negative control. The weight of the lymph nodes was well-defined higher in the positive control in comparison with the negative control and in the test group, which was treated with the 100% (v/v) test item. Counting the cells of the lymph nodes showed a positive increase of the index of the number of LN cells compared to the negative control in the positive control and in the test group with the 100 % (v/v) test item.