2-ethoxyethanol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 1992-08-04 until 1992-09-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted according to an official test guidline (OECD 406) with GLP certificate. Detailed describtion of the conducted method and obtained results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

When the test was conducted (1992) is was not mandatory to conduct a LLNA study instead of other tests such as guinea pig maximisation test.

Test material

Test material information

Constituent 1

Reference substance name:

2-ethoxyethanol

EC Number:

203-804-1

EC Name:

2-ethoxyethanol

Cas Number:

110-80-5

Molecular formula:

C4H10O2

IUPAC Name:

2-ethoxyethan-1-ol

Details on test material:

Name of the test substance as stated in the study report: 2-ethoxyethanol;
ID-number of the substance: 3630/81 402;
purity: 99.98 % (GC)

In vivo test system

Test animals

Species:

guinea pig

Strain:

other: Dunkin Hartley, Pirbright White; Bor: DHPW [SPF]

Sex:

female

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

physiological saline

Remarks:

0.9 %

Induction 2

Concentration / amount:

10 % (w/w) intradermal
100 % dermal application

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

physiological saline

Remarks:

0.9 %

Challenge 2

Concentration / amount:

10 % (w/w) intradermal
100 % dermal application

No. of animals per dose:

19 animals in the testing group
10 animals in control group 1
9 animals in control group 2

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Key result

Reading:

2nd reading

Hours after challenge:

72

Group:

test chemical

Dose level:

100 %w/w

No. with + reactions:

0

Total no. in group:

29

Remarks on result:

no indication of skin sensitisation

Results 2

Key result

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

100 %w/w

No. with + reactions:

0

Total no. in group:

29

Remarks on result:

no indication of skin sensitisation

Any other information on results incl. tables

Results on preliminary experiment:

For the intracutane application the test substance concentrations 0.25, 0.5, and 1.0 % induced only hardly visible erythema. The higher concentration (2.5, 5.0, 10 %) resulted in hardly visible erythema and oedema. According to these results a substance preparation of 10 % test substance in physiological saline was used for the intracutane induction in the main experiment.

For the dermal application no administered test substance concentration was irritating to the skin (evaluation 24 and 72 h after application. Therefore the undiluted test substance was used for the dermal application in the main experiment. As the undiluted substance was not irritant, the animals skin was pretreated with sodium dodecylsulfate in order to cause an irritation for the main experiment.

Details on preliminary intracutane application:

Concentration of test substance [ % (w/w)]	Animal 1 (24 hours post application)		Animal 2 (24 hours post application)
	Erythema and scab formation (E)	Oedema formation (O)	Erythema and scab formation (E)	Oedema formation (O)
0.25	1	0	1	0
0.50	1	0	1	0
1.00	1	0	1	0
2.50	1	1	1	1
5.00	1	1	1	1
10.00	1	1	1	1
physiological NaCl-solution	1	0	1	0

Details on preliminary dermal application:

Concentration of test substance [% (w/w)]	Animal 1			Animal 2			Animal 3
	24 h post application (p. a.)	48 h p. a.	72 h p. a.	24 h p. a.	48 h p. a.	72 h p. a.	24 h p. a.	48 h p. a.	72 h p. a.
2.5	0 Erythema and scab formation (E), 0 Oedema formation (O)	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O
25.0	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O
50.0	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O
100	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O	0 E, 0 O

Results on main experiment:

The weight gain during the study period was normal for the 19 testing and 19 control animals. For the treated animals no toxic effects were visible during the study period.

Intracutane induction (day 0):

One hour after the intracutane injection of Freund's Complete Adjuvant (FCA, 50 % in physiological NaCl) all test and control animals showed medium to heavy erythema and oedema. After 24 hours all animals showed heavy erythema (deeply injured) and heavy oedema.

The injection of the test substance (10 % in physiological NaCl solution) showed one hour after the application only hardly obvious irritation in all animals. 24 hours after the application an evaluation of these injection sites were no more possible because of the heavy skin reactions at the FCA injection sites.

The injection sites of all control animals, which have only been treated with the vehicle (physiological NaCl), showed after 1 hour and 24 hours comparable weak reactions as in the testing animals treated with 10 % of the test substance.

The mixed injection of test substance with FCA (1 + 1 dilution with physiological NaCl) resulted in all test animals one hour and 24 hours after the application heavy erythema with deep injuries (scab) and heavy oedema.

The combined injection of FCA and physiological NaCl resulted one hour after the application in medium erythema and medium oedema in all control animals. 24 hours after the application the results showed heavy erythema with deep injuries (scab) and heavy oedema in all control animals.

Dermal induction (day 7):

Pretreatment of the cropped skin with sodium dodecylsulfate resulted in reddening and swelling of the skin of all testing and control animals.

Removal of the occlusively fixed patches (positioned at the injection sites treated with FCA, 50 % in physiological NaCl) resulted in heavy erythema with deep injuries in all animals (testing and control) 49 and 72 hours post application. The injection sites were partly bleeding or covered with scab. Additionally heavy oedema were observed.

The injection sites treated with test substance (10 % in physiological NaCl) and only with vehicle could not be evaluated individually 49 and 72 hours post application, because the whole application area was irritated. Flakes of skin were visible at this area 72 hours post application.

The injection sites treated with 10 % of the test substance in FCA (1 + 1 dilution with physiological NaCl) showed in all animals 49 and 72 hours after the application heavy erythema with deep injuries (partly bleeding), and heavy oedema.

The injection sites treated with FCA and physiological NaCl (1 + 1 dilution) in the control animals showed comparable results as observed in the testing group 49 and 72 hours post application.

Challenge (day 21):

48 and 72 hours after the application the 19 testing animals as well as the 10 animals from control group 1 showed no irritation of the skin at the application site (no animals with erythema nor oedema). Because of this result, a second challenge was not conducted.

Overall result:

The test substance 2 -ethoxyethanol showed no sensitising potential to the skin of guinea pigs as the dermal reaction of the testing group according to the challenge was equal (no irritation) to that of the control animals.

Treatment group	Animal number	sensibilised animals
Testing group	19	0
Control group 1	10	0

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

According to the results of the maximisation test in guinea pigs (Magnusson and Kligman) the test substance 2-ethoxyethanol was not sensitising to the skin of the animals.