(3-methoxy-2-methylpropyl)benzene

Endpoint summary

Description of key information

- GPMT, not sensitising (OECD 406, GLP, K, Rel. 1)
- Not sensitising in humans at 50 % (HRIPT).

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From September 20 to October 28, 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

At the time of study completion (1995), the LLNA OECD test method was not adopted.

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: D.Hall, Burton-on-Trent, UK.
- Weight at study initiation: 370-425 g (topical irritancy ranging study); 433-538 g (main study)
- Housing: Animals were housed in groups of up to 5 in stainless steel grid bottomed cages.
- Diet: Pelleted diet, SQC FD1 guinea pig diet with added vitamin C (Special Diets Services, Witham, Essex), ad libitum
- Water: Mains drinking water, ad libitum
- Acclimation period: 5 days (preliminary study); 19 days (main study)

ENVIRONMENTAL CONDITIONS
- Temperature: 19-22 °C
- Humidity: 44-67 %
- Photoperiod: 12 h dark / 12 h light

IN-LIFE DATES: From: September 20, 1995 To: October 28, 1995

Route:

intradermal

Vehicle:

paraffin oil

Concentration / amount:

10 % v/v

Day(s)/duration:

Day 1

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Concentration / amount:

100 % v/v

Day(s)/duration:

Day 8 / 48 hours

Adequacy of induction:

non-irritant substance, but skin pre-treated with 10% SDS

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

unchanged (no vehicle)

Concentration / amount:

10 % v/v

Day(s)/duration:

Day 22 / 24 hours

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

10 and 20 animals for control and treatment group, respectively

Details on study design:

SIGHTING TEST:
- Intradermal injection ranging study: One guinea pig was used in this phase, which received 0.1 mL aliquots of intradermal injections of test material at 0.5, 1, 5, 10, 25 and 50 % v/v in light liquid paraffin. The animal was observed for a period of 6 days and any response noted at each injection site. The results of the intradermal range finding study, indicated that a 10 % v/v concentration of the test article in light liquid paraffin could be used intradermally without producing an unacceptable irritant response.
- Topical irritancy ranging study: Four guinea pigs were applied topically with test material at 12.5, 25 and 50 % v/v in diethyl phthalate and undiluted under occlusive patch for 24 h and evaluated for skin reactions at 24 and 48 h after removal of dressing. The results indicated that undiluted test article was non-irritant and therefore suitable for use for both the topical induction and challenge phases of the main study.


MAIN STUDY
A. INDUCTION EXPOSURE: INTRADERMAL
- No. of exposures: One
- Test groups: Intradermally injected with 3 injections (0.1 mL each) of 50 % emulsion of Freund’s Complete Adjuvant and water; test article (10 % v/v) in light liquid paraffin; test article at a final concentration of 10 % v/v in FCA/water (1:1), on Day 1.
- Control group: Intradermally injected with 3 injections (0.1 mL each) of 50 % emulsion of Freund’s Complete Adjuvant and water; light liquid paraffin; light liquid paraffin in FCA/water (1:1), on Day 1.
- Exposure period: 6 days
- Site: Dorsal area between the shoulder
- Evaluation: 24 h after administration of the intradermal injection

Six days after administration of the intradermal injections, the injection sites were clipped free of fur. As the results of the topical range finding study indicated that undiluted test article was non-irritant, 10 % sodium lauryl sulphate in light liquid paraffin was applied to the test and control animals in an attempt to produce local irritation.

B. INDUCTION EXPOSURE: TOPICAL
- No. of exposures: One, on Day 8
- Exposure period: 48 h
- Test groups: Filter paper patch (4 cm x 2 cm) saturated with undiluted test material was applied topically via occlusive dressing.
- Control group: Filter paper patch (4 cm x 2 cm) saturated with vehicle (diethyl phthalate) alone was applied topically via occlusive dressing.
- Site: Same intradermally injected area of shoulder region
- Frequency of applications: Single application
- Evaluation: 24 h after removal of the topical induction patches in both test and control groups

C. CHALLENGE EXPOSURE: TOPICAL
- No. of exposures: One
- Day of challenge: Day 22
- Exposure period: 24 h
- Filter paper patch (2 cm x 2 cm) saturated with undiluted test material was applied to the left flank of all test and control animals. The right flank of all animals was similarly treated with patches saturated with the vehicle (diethyl phthalate) via occlusive dressing.
- Evaluation (h after removal of challenge patch): 24 and 48 h

OTHER:
- Body weight of each animal was recorded at the start (Day 1) and end of the study (Day 25).

Challenge controls:

None

Positive control substance(s):

yes

Remarks:

Hexyl cinnamic aldehyde at 25 % v/v concentration in light liquid paraffin (intradermal induction), 50 % v/v concentration in ethanol (topical induction) and 30 % v/v concentration in acetone (topical challenge) (September 20 to October 14,1995)

Positive control results:

Hexyl cinnamic aldehyde is a sensitizer under the conditions of this study.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

undiluted

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

undiluted

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

Diethyl phthalate

No. with + reactions:

0

Total no. in group:

9

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

Diethyl phthalate

No. with + reactions:

0

Total no. in group:

9

Remarks on result:

no indication of skin sensitisation

Following challenge with undiluted test article, none of the test animals responded positively at the 24 or 48 h observation, resulting in a response incidence of 0 %. None of the test animals responded positively to challenge with the vehicle at any of the observations.

 

One control animal was killed in extremis on day 10 of the study. A post mortem examination revealed a prolapsed rectum; the colon was moderately distended with gas.

 

None of the remaining 9 control animals responded positively to challenge with either undiluted of the test article or the vehicle (diethyl phthalate), at any of the observations, resulting in a response incidence of 0 %.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the test conditions, the test material is not classified according to the annex VI of the Regulation (EC) No. 1272/2008 (CLP) and according to the GHS.

Executive summary:

In a Magnusson & Kligman maximisation study (GPMT) performed according to OECD Guideline 406 and in compliance with GLP, 20 female Dunkin-Hartley guinea pigs were induced with three pairs of intradermal injections (0.1 mL each) of 50 % emulsion of Freund’s Complete Adjuvant and water; 10 % concentration of the test article in light liquid paraffin; 10 % concentration of the test article in FCA/water (1:1), on Day 1 on three different sites on dorsal area between the shoulder. Control group of 10 females was intradermally induced with 0.1 mL of 50 % emulsion of Freund’s Complete Adjuvant and water; light liquid paraffin; light liquid paraffin in FCA/water (1:1), on Day 1. On Day 8, the same injected area was topically induced with undiluted test article by occluded filter paper patch for 48 h in test group, whereas control group was applied with vehicle (Diethyl phthalate) alone. On Day 22, a challenge filter paper patch of undiluted test article applied to the left flank and diethyl phthalate alone applied to the right flank of all test and control animals. The test concentrations for the main study were determined from a sighting study.

 

Following challenge with undiluted test article, none of the test animals responded positively at the 24 or 48 h observation, resulting in a response incidence of 0 %. None of the test animals responded positively to challenge with the vehicle at any of the observations. One control animal was killed in extremis on day 10 of the study. None of the remaining 9 control animals responded positively to challenge with either undiluted of the test article or the vehicle (diethyl phthalate), at any of the observations, resulting in a response incidence of 0 %. A known sensitizer, hexyl cinnamic aldehyde which induced skin sensitization indicating the validity of the study.

 

Under the test conditions, the test material is not classified according to the annex VI of the Regulation (EC) No. 1272/2008 (CLP) and according to the GHS.

This study is considered as acceptable and satisfies the requirement for sensitisation endpoint.

Reference 2

Endpoint:

skin sensitisation: in vitro

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

A key study was identified (Toxicol, 1995). This Magnusson & Kligman maximisation study (GPMT) was performed according to OECD Guideline 406 and in compliance with GLP. Guinea pigs (10 animals for test grou^, 5 animals for control group) were induced with three pairs of intradermal injections (0.1 mL each) of 50 % emulsion of Freund’s Complete Adjuvant and water; 10 % concentration of the test article in light liquid paraffin; 10 % concentration of the test article in FCA/water (1:1), on Day 1 on three different sites on dorsal area between the shoulder. Control group of 10 females was intradermally induced with 0.1 mL of 50 % emulsion of Freund’s Complete Adjuvant and water; light liquid paraffin; light liquid paraffin in FCA/water (1:1), on Day 1. On Day 8, the same injected area was topically induced with undiluted test article by occluded filter paper patch for 48 h in test group, whereas control group was applied with vehicle (Diethyl phthalate) alone. On Day 22, a challenge filter paper patch of undiluted test article applied to the left flank and diethyl phthalate alone applied to the right flank of all test and control animals. The test concentrations for the main study were determined from a sighting study.

 

Following challenge with undiluted test article, none of the test animals responded positively at the 24 or 48 h observation, resulting in a response incidence of 0 %. None of the test animals responded positively to challenge with the vehicle at any of the observations. One control animal was killed in extremis on day 10 of the study. None of the remaining 9 control animals responded positively to challenge with either undiluted of the test article or the vehicle (diethyl phthalate), at any of the observations, resulting in a response incidence of 0 %. A known sensitizer, hexyl cinnamic aldehyde which induced skin sensitization indicating the validity of the study.

 

Under the test conditions, the test material is not classified as skin sensitizer.

A human repeated insult patch test in human has been performed with the substance at up to 50 % (HRL, 2011). Under the conditions employed in this study, there was no evidence of sensitisation to the test material at 50 %.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Harmonized classification:

The substance has no harmonized classification according to the Regulation (EC) No. 1272/2008 .

Self-classification:

Based on the available data, the substance is not classified as skin sensitizer according to the Annex VI of the Regulation (EC) No. 1272/2008 (CLP) and according to the GHS.

No data was available for respiratory sensitisation. However, this substance is not a skin sensitizer, therefore according to Figure R.7.3 -2 of the Chapter R.7 (V 4.1 - October 2015) the chemical is not considered as a respiratory sensitizer.