1,2-diethoxybenzene

Endpoint summary

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:

from 2004-03-22 to 2004-10-22

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP study performed according to OECD guideline N° 406. No detail on the test animal and no data on the positive control.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

Remarks:

: no detail on the test animal and no data on the positive control.

Principles of method if other than guideline:

Not applicable

GLP compliance:

no

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

OECD Guide-line 406 "Skin Sensitisation" method (GMPT) was performed before the LLNA was set as preferred test method.

Species:

guinea pig

Strain:

not specified

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: no data
- Age at study initiation: no data (young healthy adult animals)
- Weight at study initiation: no data
- Housing: no data
- Diet (e.g. ad libitum): specific diet for guinea pigs
- Water (e.g. ad libitum): drinking water, no more detail.
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C (+/-3°C)
- Humidity (%): 30-70%
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12 hrs dark/12 hrs light

IN-LIFE DATES: no data

Route:

intradermal and epicutaneous

Vehicle:

other: deionized water

Concentration / amount:

- Intradermal induction: 12% in dieonized water
-Topical induction: 100% in dieonized water (0.5mL)
-Topical challenge: 100% in dieonized water (0.5mL)

Route:

epicutaneous, occlusive

Vehicle:

other: deionized water

Concentration / amount:

- Intradermal induction: 12% in dieonized water
-Topical induction: 100% in dieonized water (0.5mL)
-Topical challenge: 100% in dieonized water (0.5mL)

No. of animals per dose:

20 animals for the test group
10 animals for the control group

Details on study design:

RANGE FINDING TESTS:
One animal was exposed by intradermal injection to the test item at 100, 75 and 50% of concentration, and a second animal received 25, 12 and 6% -for each concentration, one pair of injections was made, one of each pair lies on each side of the midline. Evaluations were done 24 hours after injections.
Three animals were exposed by topical application to the test item. One animal received the test substance at 100% and the two others at 50 and 25%. Evaluations were done 48 hours after topical applications.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- Exposure period: Day 0 (injection) and day 7 (topical)
- SLS application: yes (10% in vaseline)
- Test groups: test substance (12% in deionized water) + test substance 12% in FCA
- Control group: deionized water in FCA
- Site: for each concentration, one pair of injections was made, one of each pair lies on each side of the midline
- Frequency of applications: the topical application was performed one week following the intradermal injection. Single exposure in each case
- Duration: Day 0 to Day 20 (with a rest period from Day 9 to Day 20)
- Concentrations: 12% (injection), 100% (topical)

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: Day 21
- Exposure period: 24 hours
- Test groups and control group: topical application of the test substance in deionized water (one flank) and deionized water alone (other flank)
- Site: right flank (test material) and left flank (vehicle)
- Concentrations: 100% (wetted with deionized water, 0.5 mL)
- Evaluation (hr after challenge): 24 and 48 hours after removal of the dressing

OTHER:
Magnusson and Kligman grading score for the evaluation of challenge:
* No visible change..........0
*Discrete or patchy erythema.........1
*Moderate and confluent erythema......2
*Intense erythema and swelling.............3

Challenge controls:

No data

Positive control substance(s):

not specified

Positive control results:

No data

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

100%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

no data

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no data.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

100%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

no data

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 100%. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no data.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

-

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no data

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: -. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no data.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

-

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

no data

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: -. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: no data.

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Remarks on result:

other: no data

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Remarks on result:

other: no data

Table 7.4.1/1:Results of the preliminary intradermal injection with two animals.

Animal number	Test item concentration	Oedema/Erythema score (24 hours)
01	100%	3
	75%	3
	50%	2
02	25%	1
	12	1
	6%	0

 

Table 7.4.1/2:Results of the preliminary topical application with three animals.

Animal number	Test item concentration	Oedema/Erythema score (48 hours)
01	100%	0
02	50%	0
03	25%	0

Table 7.4.1/3: Reaction at challenge at 24 h and 48 h in negative control group and test group (100%)

Animal number	Reaction at challenge
	24 h	48 h
Negative Control Group
01	0	0
02	0	0
03	0	0
04	0	0
05	0	0
06	0	0
07	0	0
08	0	0
09	0	0
10	0	0
Test Group (100%)
01	0	0
02	0	0
03	0	0
04	0	0
05	0	0
06	0	0
07	0	0
08	0	0
09	0	0
10	0	0
11	0	0
12	0	0
13	0	0
14	0	0
15	0	0
16	0	0
17	0	0
18	0	0
19	0	0
20	0	0

 

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of this test, ORTHO-DIETHOXY BENZENE (ODEB) does not induce delayed contact hypersensitivity in guinea pigs. The test substance was therefore considered as not sensitizing and not classified according to the CLP Regulation (EC) N°1272/2008 and of the Directive 67/548/EEC criteria.

Executive summary:

In a non- GLP skin sensitisation study (Siqueira, 2004), male guinea pigs were used to test the skin contact sensitisation potential of ortho-Diethoxybenzene (ODEB). The method of Guineapig maximisation test was used (OECD 406).

In a preliminary study, the skin irritation potential of the test item was assessed in two animals after an intradermal injection (6, 12, 25, 50, 75 and 100%) and on three animals following a topical application (25, 50 and 100%). Based on the results of this pilot study, the concentration of the test substance used in the induction phase, intradermal and topical applications were, respectively, 12% in deionized water and 100% for the main study, and in the challenge phase the tested concentration was 100%.

In the main study performed on 20 animals for the test group and 10 animals for the control group, three test sites were tested in each animal. In the first induction stage intradermal injections of

the test item (12% in deionized water) +/- Freund Complete Adjuvant or with the vehicle were performed on each animal. One week later, the animals were pre-treated with sodium lauryl sulphate (to promote a skin irritation) and then topically exposed to the test item at 100% (wetted with deionized water) or the vehicle. Two weeks following this second induction stage, animals were challenged by a topical application of the test item at 100% (wetted with deionized water) for 24 hours. At 24 and 48 hours after the challenge phase at concentrations of 100%, it was not observed any skin reaction in the animals receiving the test substance or deionized water. As all tested animals (20) didn’t show hypersensivity with the ODEB, no classification is warranted according to the CLP Regulation (EC) N°1272/2008 and of the Directive 67/548/EEC criteria.

 

This skin sensitisation study is classified as acceptable. It satisfies the guideline requirement for a skin sensitisation in the guinea pig.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Only one study was available for this endpoint and was considered as the key study and had reliability 2. In a dermal sensitization study with 1,2 -diethoxybenzene in deionized water, thirty guinea pigs were tested using the method of Guinea pig maximisation test. Twenty animals were used for the treatment group and ten for the control group. Induction was carried out in 2 phases: - Phase 1: Day 0 animals were injected by the intradermal route with 1,2 -diethoxybenzene (12% in deionized water) +/- Freund Adjuvant or with the vehicle. - Phase 2: a 48 hours topical occlusive application was performed Day 7 with 1,2 -diethoxybenzene at 100% (wetted with deionized water) or the vehicle. The control and test animals were challenged topically 2 weeks after the topical induction application with 1,2 -diethoxybenzene at 100% (wetted with deionized watter) for 24 hours. The challenge sites were evaluated 24 and 48 hours after the removal of the patches. The reaction were graded for erythema and oedema according to a numerical scale. In this study, none of the test animals (20) showed hypersensivity with the o-Diethoxybenzene. Therefore, given the absence of positive reactions, o-Diethoxybenezene is not classified as a skin sensitizer.

Migrated from Short description of key information:
Negative in guinea pigs maximisation test (OECD 406, Kr: 2), and therefore classified as not skin sensitizer.

Justification for selection of skin sensitisation endpoint:
Only one study available

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information:

Justification for selection of respiratory sensitisation endpoint:
Study is not required since the tested substance is a transported isolated intermediate (ECHA. Guidance on intermediates. Version: 2, December 2010)

Justification for classification or non-classification

- Skin sensitisation:

As none of the test animals (20) showed hypersensivity with the o-Diethoxybenzene, no classification is warranted according to the CLP Regulation (EC) N°1272/2008 and of the Directive 67/548/EEC criteria.

- Respiratory sensitisation:

No classification is possible due to lack of data.