1-ethoxy-2,3-difluorobenzene

Endpoint summary

Description of key information

Skin sensitisation in vivo (OECD TG 406): no skin sensitisation potential (reference 7.4.1 -1).

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000-02-08 to 2000-03-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

July 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Version / remarks:

July 1996

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

This study was conducted due to non-REACH regulatory requirements. With the existing data from this study not only being acceptable but of good quality (Klimisch Score 1), this study precludes the need for an additional LLNA study. In addition, a supplementary LLNA study would violate the ECHA objectives with regards to animal welfare.

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Winkelmann GmbH, Borchen, Germany
- Females nulliparous and non-pregnant: not specified
- Age at study initiation: about 6 weeks
- Weight at study initiation: 351 g (range from 313 to 399 g)
- Housing: in groups of two in a Makrolon cage type with a shelter placed on mobile racks
- Diet ad libitum, (Altromin Standard Diät TPF® 3012)
- Water: ad libitum, tap water
- Acclimation period: at least 7 days
- Indication of any skin lesions:

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 23
- Humidity (%): 40 - 64
- Photoperiod (hrs dark / hrs light): 12/12

Route:

intradermal

Vehicle:

physiological saline

Concentration / amount:

25 g/L / 0.1 mL

Day(s)/duration:

1

Adequacy of induction:

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

Route:

intradermal

Vehicle:

other: Freund's complete adjuvant with test substance + physiological saline

Concentration / amount:

25 g/L / 0.1 mL

Day(s)/duration:

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:

undiluted / 1 mL

Day(s)/duration:

7 / 48 hours

Adequacy of induction:

highest technically applicable concentration used

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

physiological saline

Concentration / amount:

100 g/L / 0.5 mL

Day(s)/duration:

Day 21 / 24 hours

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

Number of animals in test group: 20
Number of animals in negative control group: 10

Details on study design:

RANGE FINDING TESTS:
To determine the concentrations suitable for the main study, a pretest with single intradermal or topical administrations of the vehicle and of test substance preparations was performed. Intradermal (i.d.) injections were given to one animal. Four further animals were used to determine the topical concentrations for the main study. Two of the guinea pigs were exposed for 48 hours without pretreatment to determine the concentration for the dermal induction. The other two animals were treated according to the control group including intradermal injections with FCA. One week after topical induction the two animals of the pretest group were exposed for 24 hours to different test material concentrations to find out the challenge concentration. In the pretest the following concentrations were used:
1. Sodium chloride solution: intradermal
2. Test substance with sodium chloride solution as vehicle:
intradermal: 50, 25, 10, 5, and 1 g/L
topical: undiluted and 500, 100, and 10 g/L
topical with FCA: 500, 100, 10, and 1 g/L

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 6 intradermal and 2 topical exposures
- Exposure period: Day 1 (intradermal) and Day 14 (topical)
- Test groups:
intradermal:

1. Injection site: cranial
complete Freund's adjuvant (DIFCO LAB.) diluted 1:1 with physiological saline solution

2. Injection site: medial
25 g/L test substance formulated in physiological saline solution

3. Injection site: caudal
25 g/L test substance formulated at equal parts in physiological saline solution and complete Freund's adjuvant

topical:
Test item group: 0.5 mL 100 % test substance

- Control group: same treatment for intradermal and topical application without test substance.
- Site: shoulder region
- Frequency of applications: once
- Duration: 7 days (intradermal), 48 hours (topical)
- Concentrations: 25 g/L interadermal; 100 % topical

B. CHALLENGE EXPOSURE
- No. of exposures: 1 exposure
- Day(s) of challenge: 21
- Exposure period: 24 hours
- Test groups: undiluted test substance loaded on hypoallergenic patch
- Control group: like test group
- Site: shoulder region
- Concentrations: 10 % (100 g/L)
- Evaluation (hr after challenge): 24 and 48 hours

Positive control substance(s):

yes

Remarks:

alpha-hexylcinnamaldehyde

Positive control results:

5 g/L alpha-hexylcinnamaldehyde in physiological saline led to the expected results. 50 % positive reactions were observed after challenge application.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

100 g/L (10 %)

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:

100 g/L (10 %)

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:

100 g/L (10 %)

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

100 g/L (10 %)

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

5 g/L

No. with + reactions:

5

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

5 g/L

No. with + reactions:

3

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Interpretation of results:

GHS criteria not met

Conclusions:

No skin sensitising properties were observed in the guinea pig maximisation test.

Executive summary:

In a dermal sensitisation study with the test substance in in physiological saline, 30 female Dunkin Hartley guinea pigs (20 animals for the test item group and 10 control animals) were tested using the guinea pig maximisation test (GMPT) in accordance with OECD guideline 406 and EU method B.6. Animals were between about 6 weeks old and exhibited a weight range of 313 - 399 g at the beginning of the study.

Induction included intradermal injection of test material preparation (25 g/L with and without Freund's complete adjuvant) on day 1, and topical application of undiluted test material on day 8.

Challenge by topical application of the test material preparation (100 g/L) was performed two weeks after topical induction.

The challenge using a 10 % test item formulation led to no skin effects in the animals of the treatment group or of the control group.

In summary, under the conditions of the maximization test and with respect to the evaluation criteria the test item therefore exhibits no skin-sensitization potential.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a dermal sensitisation study with the test substance in in physiological saline, 30 female Dunkin Hartley guinea pigs (20 animals for the test item group and 10 control animals) were tested using the guinea pig maximisation test (GMPT) in accordance with OECD guideline 406 and EU method B.6. Animals were between about 6 weeks old and exhibited a weight range of 313 - 399 g at the beginning of the study.

Induction included intradermal injection of test material preparation (25 g/L with and without Freund's complete adjuvant) on day 1, and topical application of undiluted test material on day 8.

Challenge by topical application of the test material preparation (100 g/L) was performed two weeks after topical induction.

The challenge using a 10 % test item formulation led to no skin effects in the animals of the treatment group or of the control group.

In summary, under the conditions of the maximization test and with respect to the evaluation criteria the test item therefore exhibits no skin-sensitization potential.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The available experimental test data is reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. As a result the substance is considered not to be classified for skin sensitisation under Regulation (EC) No 1272/2008, as amended for the twelfth time in Regulation (EU) No 2019/521.