4-isobutyl-2-methylbenzaldehyde

Endpoint summary

Description of key information

The primary cutaneous irritation index (P.C.I.) was determined to be 1.2, and the test substance was evaluated as “slightly irritant”.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant guideline study, available as unpublished report, no restrictions, fully adequate for assessment

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Kitayama Labes Co., Ltd; Kbl: NZW (SPF)
- Age at study initiation: 11 weeks
- Weight at study initiation: 2300 to 2472 g
- Housing: 1 animal per cage, in aluminum cages (W650 × D570 × H413 mm), Stainless-steel cascade rack and feeders; toys were used for improvement of animal welfare
- Diet: pellet diet (RC4, Oriental Yeast Co., Ltd.), ad libitum
- Water: well water admixed with sodium hypochlorite (free residual chlorine concentration: about 0.2 ppm), ad libitum
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 – 23.4
- Humidity (%): 48.5 – 63.8
- Air changes (per hr): 10 – 20
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL

Duration of treatment / exposure:

- Initial test: 3 min, 60 min and 4 hours
- Confirmatory test: 4 hours

Number of animals:

- Initial test: 1
- Confirmatory test: 2

Details on study design:

TEST SITE
- Area of exposure: In the initial test three sites (2.5 cm × 2.5 cm each) were created on the shaved area. In the confirmatory test one site of the same size was created.
- Type of wrap if used: The test substance was placed on a 2.5 cm × 2.5 cm patch (lint cloth, Yamato Kojo Co., Ltd.) attached with a 5 cm × 5 cm non-woven adhesive bandage (Mesh-pore®, Nichiban Co., Ltd.) and placed on each application site. The application sites were occluded by an adhesive elastic bandage (Elastopore®, Nichiban Co., Ltd.).

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Each occlusion was released and each application site was cleaned with absorbent cotton moisturized with lukewarm water.
- Time after start of exposure: Initial test: 3 minutes, 60 minutes, and 4 hours, confirmatory test: 4 hours

SCORING SYSTEM: The skin conditions of the 3 and 60 minutes application sites (initial test) at 1 hour after patch removal, and those of the 4 hours application site (all animals) at 1, 24, 48, 72 hours and 7 days after patch removal were scored based on the evaluation criteria for erythema and oedema formations to calculated the Primary Cutanous Irritation Index.

Irritation parameter:

other: primary cutaneous irritation index

Basis:

mean

Time point:

other: 1 - 48 h

Score:

1.2

Max. score:

8

Reversibility:

fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: 24 - 72 h

Score:

1.7

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

other: 24 - 72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

other: 24 - 72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #1

Time point:

other: 24 - 72 h

Score:

0.7

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #2

Time point:

other: 24 - 72 h

Score:

0

Max. score:

4

Irritation parameter:

edema score

Basis:

animal #3

Time point:

other: 24 - 72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

The very slight erythema (erythema score 1) was observed in initial test at 3 and 60 minutes application sites at 1 hour after patch removal.
As a result of 4-hour exposure, very slight erythema (erythema score 1) was observed in all animals at 1 hour after patch removal. In addition, well defined erythema (erythema score 2) and very slight oedema (oedema score 1) were observed in one animal at 48 and 72 hours after patch removal. These reactions disappeared from all animals by 7 days after patch removal. Therefore, primary cutaneous irritation index (P.C.I.) was 1.2, and it was evaluated as “slightly irritant”.

Other effects:

No abnormal clinical signs or body weight gain was observed in any animal

Interpretation of results:

slightly irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The primary cutaneous irritation index (P.C.I.) was determined to be 1.2, and the test substance was evaluated as “slightly irritant”.

Executive summary:

The acute dermal irritation or corrosion potential of the test substance was assessed in a GLP compliant OECD 404 guideline study. The test substance was topically applied to the back skin (2.5 cm x 2.5 cm) of three male New Zealand White rabbits for 4 hours under semi-occlusive conditions. Very slight erythema (erythema score 1) was observed in all animals at 1 hour after patch removal. In addition, well defined erythema (erythema score 2) and very slight oedema (oedema score 1) were observed in one animal at 48 and 72 hours after patch removal. These reactions disappeared from all animals by 7 days after patch removal. Therefore, primary cutaneous irritation index (P.C.I.) was 1.2, and it was evaluated as “slightly irritant”.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The acute dermal irritation or corrosion potential of the test substance was assessed in a GLP compliant OECD 404 guideline study. The test substance was topically applied to the back skin (2.5 cm x 2.5 cm) of three male New Zealand White rabbits for 4 hours under semi-occlusive conditions. Very slight erythema (erythema score 1) was observed in all animals at 1 hour after patch removal. In addition, well defined erythema (erythema score 2) and very slight oedema (oedema score 1) were observed in one animal at 48 and 72 hours after patch removal. These reactions disappeared from all animals by 7 days after patch removal. Therefore, primary cutaneous irritation index (P.C.I.) was 1.2, and it was evaluated as “slightly irritant”.

Justification for selection of skin irritation / corrosion endpoint:
Only study available, GLP compliant guideline study, available as unpublished report, no restrictions, fully adequate for assessment.

Effects on skin irritation/corrosion: slightly irritating

Justification for classification or non-classification

Based on the available information classification for skin irritation/corrosion is not warranted in accordance with EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.

As no study is available for eye irritation, classification for eye irritation is not possible in accordance with EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.