3-(p-cumenyl)-2-methylpropionaldehyde

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11-APR-2001 to 18-MAY-2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

3-(p-cumenyl)-2-methylpropionaldehyde

EC Number:

229-695-0

EC Name:

3-(p-cumenyl)-2-methylpropionaldehyde

Cas Number:

6658-48-6

Molecular formula:

C14H20O

IUPAC Name:

3-(4-isopropylphenyl)-2-methylpropanal

Specific details on test material used for the study:

Name (as stated in the report): ISOBUTYL LILIAL
Batch No.: 017898
Expiration date: 02-SEP-2001

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

Test system: Mice, CBA/CaOlaHsd
Source: Harlan Netherlands, B.V. Postbus 6174, NL-5960 AD Horst/ The Netherlands
Age: 7 - 12 weeks (beginning of acclimatization)
Body weight: 15.9 g - 21.9 g (beginning of acclimatization period)
Identification: By unique cage number and individual color code
Randomization: Randomly selected by computer algorithm at time of delivery
Acclimatization: Under test conditions after health examination. Only animals without any visible signs of illness were used for the study.
Accommodation: In groups of four in Makrolon type-3 cages with standard softwood bedding {"Lignocel", Schill AG, CH-4132 Muttenz).
Diet: Pelleted standard Kliba 3433, batch no. 07/00 mouse maintenance diet {Provimi Kliba AG, CH-4303 Kaiseraugst) available ad libitum. Results of analyses for contaminants are archived at ACC
Water: Community tap water from ltingen, available ad libitum. Results of representative bacteriological, chemical and contaminant analyses are archived at ACC.

Study design: in vivo (LLNA)

Vehicle:

other: Ethanol 70 %

Concentration:

0%(control group), 10%, 25%, 50% and 100%(undiluted) of test item concentration

No. of animals per dose:

1 dose per animal
1 test concentration per group (4 animal per group)

Details on study design:

Each test group of mice was treated by topical (epidermal) application to the dorsal surface of each ear lobe (left and right) with different test item concentrations of 10 %, 25 %, 50 % and 100 % (undiluted) in ethanol 70 %. The application volume, 25 µI, was spread over the entire dorsal surface of each ear lobe once daily for three consecutive days. A further group of mice was treated with an equivalent volume of the relevant vehicle alone (control animals). A hair dryer was used to dry the ear's surface as quickly as possible to avoid loss of test item applied.

Positive control substance(s):

other: ALPHA-HEXYLCINNAMALDEHYDE

Results and discussion

Positive control results:

ALPHA-HEXYLCINNAMALDEHYDE was regarded as a sensitizer when tested at concentrations of 1O % and 25 %. At a concentration of 5 % the test item was found to be a non-sensitizer.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Remarks:

Test item concentration 10%

Value:

3.3

Test group / Remarks:

Group 2

Results 2

Key result

Parameter:

SI

Remarks:

Test item concentration 25%

Value:

8.3

Test group / Remarks:

Group 3

Results 3

Key result

Parameter:

SI

Remarks:

Test item concentration 50%

Value:

19.8

Test group / Remarks:

Group 4

Results 4

Key result

Parameter:

SI

Remarks:

Test item concentration 100%

Value:

34.3

Test group / Remarks:

Group 5

Any other information on results incl. tables

No deaths occurred during the study period

In animals of test group 5 (100%,undiluted) hardened skin was observed at the application area of the outer ear at necropsy.

All other animals showed no test item related clinical or local signs.

The body weight of the animals, recorded at the start of acclimatization period and prior to necropsy, was within the range commonly recorded for animals of this strain and age.

Applicant's summary and conclusion

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

In this study STIMULATION INDICES of 3.3, 8.3, 19.8 and 34.3 were determined with the test item at concentrations of 10 %, 25 %, 50 % and 100 % (undiluted) in ethanol 70 %.
A test item is regarded as a sensitizer in the LLNA if the exposure to at least one concentration of the test item resulted in an incorporation of 3 HTdR at least 3-fold or greater than that recorded in control mice, as indicated by the STIMULATION INDEX.
Therefore, the test item ISOBUTYL LILIAL is regarded as a sensitizer when tested at the described concentrations.

Executive summary:

In this study STIMULATION INDICES of 3.3, 8.3, 19.8 and 34.3 were determined with the test item at concentrations of 10%,25%,50%and 100%(undiluted) in ethanol 70 %.

A test item is regarded as a sensitizer in the LLNA if the exposure to at least one concentration of the test item resulted in an incorporation of3HTdR at least 3-fold or greater than that

recorded in control mice, as indicated by the STIMULATION INDEX.

Therefore, the test item ISOBUTYL LILIAL is regarded as a sensitizer when tested at the described concentrations. It meets the criteria for a skin sensitization classification SS Cat. 1B according to the CLP criteria.