Registration Dossier

Administrative data

Description of key information

In vivo skin sensitisation studies were conducted with the dissociation products of MEA-LAS. The results of these studies are summarised below. Overall, the results indicate no evidence for skin sensitisation.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Referenceopen allclose all

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
January 14, 1985-February 7, 1985
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
1981; Directive 179/831 Annex, Part B
GLP compliance:
yes
Type of study:
other: maximization test
Justification for non-LLNA method:
The study was conducted before the requirement for LLNA testing came into force.
Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 6-8 weeks
- Weight at study initiation: 200-350 g
- Housing: Makrolon cages, 5 per cage
- Diet (e.g. ad libitum): 8GP17 guinea pig food, ad libitum
- Water (e.g. ad libitum): ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2 degree C
- Humidity (%): 60 +/- 20%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 hrs light/12 hrs dark

Route:
other: intracutaneously and epicutaneously
Vehicle:
water
Concentration / amount:
Induction concentration was 25% in water and Freund's Adjuvant; the challenge concentration was 12.5% in deionized water
Route:
other: no data
Vehicle:
water
Concentration / amount:
Induction concentration was 25% in water and Freund's Adjuvant; the challenge concentration was 12.5% in deionized water
No. of animals per dose:
10 male and 10 female
Details on study design:
Induction
Induction was first done by intradermal injection. Test animals were injected with 0.1 ml Freund Complete Adjuvant (FCA), 0.1 ml of 25% test substance in water, and 0.1 ml test substance in FCA in water (final concentration 25%). Control group was treated in a similar manner with only FCA and water. On day 7, a second, epicutaneous challenge was done. 0.5 ml of test susbtance (25%) was placed on gauze, and then placed on the animals. The animals were than bandaged, and the test substance remained in contact for 48 hrs. Control animals were exposed to vehicle only.

Challenge
0.2 ml of 12.5 % test article was placed on gauze, which was then placed on the test and control animals. Gauze containing only vehicle was placed on the left flank. The exposure lasted 24 hrs. Observations for irritation were made at 24 and 48 hrs after the end of exposure. Skin was scored for irritation using the Draize scale.
Positive control substance(s):
not specified
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
0.2 ml of 12.5% test solution
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no positive responses were observed
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: test group. Dose level: 0.2 ml of 12.5% test solution. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: no positive responses were observed.
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
0.2 ml 12.5% test solution
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 0.2 ml 12.5% test solution. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
0.2 ml 12.5% test solution
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 0.2 ml 12.5% test solution. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
2nd reading
Hours after challenge:
72
Group:
negative control
Dose level:
0.2 ml 12.5% test solution
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 72.0. Group: negative control. Dose level: 0.2 ml 12.5% test solution. No with. + reactions: 0.0. Total no. in groups: 10.0.
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Remarks on result:
not measured/tested
Interpretation of results:
not sensitising
Conclusions:
The test substance is not sensitizing to skin.
Executive summary:

This test determined the potential of the test substance to be sensitizing to skin. 10 male and 10 female guinea pigs were given intradermal injections of 25% test solution. Control animals (5 male and 5 female) were given injections of vehicle only. One week later, a second induction was done by dermal exposure to 25% test solution for 24 hrs. Control animals were again exposed to vehicle only. On day 21, the challenge exposure was performed. All animals were exposed to 12.5% test solution dermally. Exposure was for 24 hrs, with observations made at 48 and 72 hrs after the start of exposure. No positive reactions were noted. The test substance is not sensitizing.

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Basic data given. Data were obtained from a reliable secondary source (MAK. 33rd update, 2001).
Principles of method if other than guideline:
Guinea pig maximisation test
GLP compliance:
not specified
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The study was conducted before the requirement for LLNA testing came into force.
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
not specified
Details on test animals and environmental conditions:
Albino guinea pigs of the Dunkin-Hartley strain were obtained from SahIins Försöksdjursfarm Malmö, Sweden) and kept in groups of three in plastic cages.
Route:
intradermal and epicutaneous
Vehicle:
water
Concentration / amount:
0.6% (intradermal) and 10.3% (epicutaneous) for induction
No.:
#1
Route:
epicutaneous, open
Vehicle:
water
Concentration / amount:
0.41, 2.05 and 4.1% for challenge
No. of animals per dose:
15 animals used for the test substance (5 animals per concentration)
12 animals used for controls
Details on study design:
The GPMT protocol with the same experimental design as in a previous study on TEA (Boman et al., 1993) was followed. Groups of 15 animals were induced with either MEA, DEA or TEA and then challenged after three weeks with the inducing amine and the two others. Prior to the topical induction, pretreatment with 10% sodium dodecyl sulphate was carried out. The concentrations used for induction and challenge were based on previous experience with TEA and the concentrations of MEA and DEA were equimolar to those of TEA. The challenge reactions were read blindly 48 and 72 hours after application or the patches (Finn chambers). Two separate experiments were carried out with MEA. Control groups of twelve animals were given the same treatment (Freund's Complete Adjuvant, vehicle, occlusion, etc.) except for the inducing amine.
Challenge controls:
no data
Positive control substance(s):
no
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
4.1%
No. with + reactions:
2
Total no. in group:
15
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
2.05%
No. with + reactions:
1
Total no. in group:
15
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
0.41%
No. with + reactions:
2
Total no. in group:
15
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
4.1%
No. with + reactions:
3
Total no. in group:
15
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
2.05%
No. with + reactions:
2
Total no. in group:
15
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
0.41%
No. with + reactions:
3
Total no. in group:
15
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
0
No. with + reactions:
0
Total no. in group:
12
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
negative control
Dose level:
0
No. with + reactions:
0
Total no. in group:
12
Key result
Reading:
1st reading
Hours after challenge:
72
Group:
other: vehicle control
Dose level:
0
No. with + reactions:
2
Total no. in group:
15
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
4.1%
No. with + reactions:
1
Total no. in group:
15
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
2.05%
No. with + reactions:
2
Total no. in group:
15
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
0.41%
No. with + reactions:
1
Total no. in group:
15
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
4.1%
No. with + reactions:
1
Total no. in group:
15
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
2.05%
No. with + reactions:
1
Total no. in group:
15
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
0.41%
No. with + reactions:
0
Total no. in group:
15
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Remarks on result:
not measured/tested

After challenge with 4.1 %, 2.05 % and 0.41 % of 2-aminoethanol, 3/15, 2/15 and 3/15 animals reacted positively after 72 hours. Two out of 15 animals showed a reaction to the vehicle. Of the 12 control animals, none reacted to 2-aminoethanol or the vehicle. Possible cross reactions to 5 % of triethanolamine and 7 % of diethanolamine occurred in 3 and 2 animals, respectively. In a 2nd test, only 1 or 2 animals showed a reaction to 4.1 % and 2.05 % of 2-aminoethanol, but none of the animals reacted to 0.41 % of 2-aminoethanol or the physiological saline solution used as a vehicle in this study. Moreover, reactions to 10 % of triethanolamine and 7 % of diethanolamine were only observed in 1 and 2 animals, respectively. Of the 12 control animals none reacted to one of the ethanolamines, and 1/12 animals reacted to the vehicle after 24 hours. The test with monoethanolamine has been performed twice.

Interpretation of results:
GHS criteria not met
Conclusions:
In a guinea pig maximization test, monoethanolamine was not found to be skin sensitizer.
Executive summary:

A guinea pig maximization test was conducted to evaluate the sensitizing potential of monoethanolamine.

15 Dunkin-Hartley guinea pigs were treated with 0.6 and 10.3% (pH = 10.1) of 2-aminoethanol in water for intradermal and epicutaneous induction, respectively. Before the epicutaneous induction, the animals were treated topically with 10% sodium dodecyl sulfate. The substance used contained less than 0.1% of diethanolamine and triethanolamine. The animals were then challenged with 4.1, 2.05 and 0.41% of 2-aminoethanol.

After challenge with 4.1, 2.05 and 0.41% of 2-aminoethanol, 3/15, 2/15 and 3/15 animals reacted positively after 72 hours. Two out of 15 animals showed a reaction to the vehicle. Of the 12 control animals, none reacted to 2-aminoethanol or the vehicle. Possible cross reactions to 5 % of triethanolamine and 7 % of diethanolamine occurred in 3 and 2 animals, respectively.

The test with monoethanolamine was performed twice. In a 2nd test, only 1 and 2 animals showed a reaction to 4.1 and 2.05 % concentrations, respectively, but none of the animals reacted to 0.41 % concentration or the physiological saline solution used as a vehicle in this study. Moreover, reactions to 10 % of triethanolamine and 7 % of diethanolamine were only observed in 1 and 2 animals, respectively. Of the 12 control animals none reacted to one of the ethanolamines, and 1/12 animals reacted to the vehicle after 24 hours.

Since no statistically significant difference between actively induced animals and control animals was observed, therefore monoethanolamine is not concluded as skin sensitizer.

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From Jul,1981 to Sept, 1981
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
not specified
Type of study:
Buehler test
Justification for non-LLNA method:
The study was conducted before the requirement for LLNA testing came into force.
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Hartley-Dunkin guinea pigs were obtained from Hacking and Churchill Ltd., Abbots Ripton road, Wyton, Huntington
- Females (if applicable) nulliparous and non-pregnant: Not specified
- Age at study initiation: Young animals were taken in the study
- Weight of animals: 328-390 g for males and 307-401g for females
- Housing: Animals were either group housed (2 by sex per cage) or caged singly in grid floor polypropylene glass
- Diet: Guinea pig diet, Standard, with vitamin C, BP Nutrition (U.K.) Ltd., Stepfield, Witham, Essex, ad libitum
- Water: Mains water, ad libitum
- Acclimation period: 12 days
- Indication of any skin lesions: no information

ENVIRONMENTAL CONDITIONS
- Temperature: 19-24°C
- Relative humidity: 43-58%
- Air changes: No data
- Photoperiod: 12 hours light (artifical) /12 hours dark

- IN-LIFE DATES: no information
Route:
epicutaneous, occlusive
Vehicle:
other: distilled water
Concentration / amount:
10% v/v in distilled water was applied under the lint pad (19X25 mm) on elastoplast coverlet (38X50 mm)
Day(s)/duration:
Day 1, 8 and 15 (Once a week for three weeks)
Adequacy of induction:
not specified
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: distilled water
Concentration / amount:
10% v/v in distilled water was applied under the lint pad (19X25 mm) on elastoplast coverlet (38X50 mm)
Day(s)/duration:
Day 29 (After two weeks of induction phase, animals were once exposed to primary challenge.)
Adequacy of challenge:
not specified
No. of animals per dose:
Treatment group: 20 animals (10/sex)
Control group: 10 animals (5/sex)
Details on study design:
RANGE FINDING TESTS: Yes, range finding study was conducted in order to determine the highest non-irritant test concentration to be used in main study. Four additional animals were treated with test substance at each of the following concentration: 100% (undiluted), 10, 25, and 50% v/v. Patch was applied to four sites on shaven back of animals using 0.4 mL test substance solutions under a lint pad (19X25 mm) on an elastoplast coverlet (38*50 mm), a method similar to the induction application.

Further details about skin reactions in range finding study are present under "Any other information of results inc. tables" section.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: 6 hours
- Test groups: One test group, including 20 guinea pigs
- Control group: Control animals were not treated during induction phase
- Site: Anterior aspect of the left shoulder of each animal, test site was shaved with electric clippers on the day prior to application.
- Test procedure: Test substance was applied under a lint pad (19x25 mm) on an elastoplast coverlet (38x50 mm) and remained in contact for a period of 6 hours. The treatment was repeated on day 7 and 14 after initial exposure on the same test site which was shaved a day before each application.
- Frequency of applications: Once in a week
- Duration: 3 weeks
- Concentrations: 0.4 mL of 10% v/v monoethanolamine in distilled water

B. CHALLENGE EXPOSURE
- No. of exposures: One
- Day(s) of challenge: Two week after last induction
- Exposure period: 6 hours
- Test groups: One test group, including 20 guinea pigs
- Control group: One control group, including 10 guinea pigs
- Site: Freshly shaved left flank that had not been treated before. Test and control animals were challenged with application of patches, identical to the ones used in the induction exposure
- Concentrations: 0.4 mL of 10% v/v monoethanolamine in distilled water
- Evaluation (hr after challenge): 21 and 45 h after challenge exposure.
Challenge controls:
10 control animals (previously unexposed) were treated with 0.4 mL of 10% v/v of test substance in distilled water
Positive control substance(s):
no
Key result
Reading:
1st reading
Hours after challenge:
21
Group:
test group
Dose level:
0.4 mL of 10% monoethanolamine in distilled water
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
5 animals with grade 0.5 (slightly patchy erythema) and 4 animals with grade 1 (slight but confluent or moderate patchy erythema), none of the observations in test group exceeded the most severe control reaction (grade 1).
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
45
Group:
test group
Dose level:
0.4 mL of 10% monoethanolamine in distilled water
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
Only one animal showed skin responses of grade 0.5 (slightly patchy erythema), none of the observations in test group exceeded the most severe control reaction (grade 1).
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
21
Group:
negative control
Dose level:
10% v/v
No. with + reactions:
3
Total no. in group:
10
Clinical observations:
Three animals showed skin responses of grade 0.5 (slightly patchy erythema) and 3 animals showed grade 1 (slight but confluent or moderate patchy erythema)
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
45
Group:
negative control
Dose level:
10% v/v
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Only one animal showed skin responses of grade 0.5 (slightly patchy erythema)
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Remarks on result:
not measured/tested

Table 1: The incidence and severity of skin reactions observed in induced test animals and previously untreated control animals (Study#26195)

Groups Observation time (hr) Skin responses (Scale 0-3) Incidence (N) Severity (A)
0 0.5 1 2 3
Test 21 11 5 4 0 0 4/20 0.3
45 19 1 0 0 0 0/20 0
Control 21 4 3 3 0 0 3/10 0.5
45 9 1 0 0 0 0/10 0.1

Table 2: Skin reactions in dose range-finding study (Study#26195)

Solution concentration (% v/v) Number of animals showing skin responses (Scale 0-3)
0 0.5 1 2 3
Distilled water 0 0 2 1 1
50 3 0 1 0 0
25 3 0 1 0 0
10 0 2 2 0 0

N=Numberofanimals showing skin reponses >1.

A=Sumofskin responses divided by thenumber ofanimals tested.

Table 3:Skin reaction in test animals at challenge application (Study# 26195)

Animal  Skin reaction (hrs after challenge application)
Number Sex Weight (g) 21 45
1 M 345 0 0
2 366 0 0
3 328 0 0
4 352 0 0
5 377 0 0
6 375 0 0
7 390 0.5 0
8 384 1 0
9 374 0.5 0
10 357 0 0
11 F 363 0.5 0
12 312 1 0
13 307 0.5 0
14 350 1 0
15 401 0 0
16 353 0 0
17 364 0.5 0
18 377 1 0.5
19 333 0 0
20 346 0 0
Sum of test grades (A)   6.5 0.5
Number showing response >1 (N)   4 0
Incidence (N/20)     4/20 0/20
Severity (A/20)     0.3 0
Highest grade observed     1 0.5

Table 4:Skin reaction in control animals at challenge application (Study#26195)

Animal  Skin reaction (hrs after challenge application)
Number Sex Weight (g) 21 45
21 M 364 1 0
22 369 1 0.5
23 336 0 0
24 328 0 0
25 353 1 0
26 F 341 0.5 0
27 364 0.5 0
28 340 0 0
29 381 0 0
30 360 0.5 0
Sum of test grades (A)   4.5 0.5
Number showing response >1 (N)   3 0
Incidence (N/10)     3/10 0/10
Severity (A/10)     0.5 0.1
Highest grade observed     1 0.5

None of the observations in test group exceeded the most severe control reaction (grade 1).

Interpretation of results:
GHS criteria not met
Conclusions:
In a delayed contact hypersensitivity (Buehler) test, Monoethanolamine (10%; BASF/Shell, 50:50 mix) in distilled water was determined to be non-sensitizing when applied topically to Hartley-Dunkin guinea pigs.
Executive summary:

The skin sensitization potential of Monoethanolamine (10%; BASF/Shell, 50:50 mix) was determined following a method comparable to the OECD Guideline 406 (Skin Sensitisation).

A total of 30, Hartley Dunkin guinea pigs (source: Hacking and Churchill Ltd, Huntington) weighing 328-390 g for males and 307-401g for females were used in this study. The animals were maintained on laboratory conditions for 12 days. They were given Guinea pig diet with vitamin C, BP nutrition (U.K) Ltd., Stepfield, Witham, Essex and water ad libitum. 20 and 10 guinea pigs were used in test treatment and control groups, respectively.

A range finding study was also conducted using 4 additional guinea pigs to determine the highest non-irritating concentration for the primary challenge. For this purpose, the test substance was tested at 100 (undiluted), 10, 25, and 50% in distilled water. It was estimated that a concentration of 10% v/v was approximate threshold non-irritant concentration and was selected for main study.

One day prior to induction application, the upper left quadrant of the back of the animals was clipped with an electronic clipper. On the day of induction, patches were applied using a Duke Elastopatch coverlet with 0.4 mL of 10% test substance in distilled water for 6 hours. The patches were reapplied to the same site once every week for a total of 3 weeks.

After 2 weeks rest period from the last induction exposure, the test and primary challenge control animals were challenged at a fresh site with 0.4 mL of 10% test substance. Approximately 18 hours after the primary challenge, test sites were depilated and were scored after 3 hours of depilation for a 21 hour reading. The sites were scored again after 24 hours for a 45-hour reading.

During the primary challenge, the most severe control reaction was graded as 1 in 3 animals at 21 hour- reading. The four test animals showed the same grade as control at the 21 hour score reading. At 45-hour reading, one animal from both control and test animals showed reactions graded as 0.5. Since, test animals did not exceeded the most severe control reaction, the observed reactions in test animals were not due to sensitization.

Based on above observations, Monoethanolamine (10%; BASF/Shell, 50:50 mix) was determined to be non-sensitizing in delayed contact hypersensitivity (Buehler) test when applied topically to Hartley-Dunkin guinea pigs.

This skin sensitization study is classified as acceptable, and is comparable to the guideline requirements of the OECD 406 method.

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1975
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
no
Remarks:
pre-dates GLP
Type of study:
Buehler test
Justification for non-LLNA method:
The study was conducted before the requirement for LLNA testing came into force.
Species:
guinea pig
Strain:
other: Hartley albino strain
Sex:
not specified
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: The albino guinea pigs were obtained from Sweetwater Farms
- Age at study initiation: Not reported
- Weight at study initiation: 350 - 400 g
- Housing: Not reported
- Diet: Purina guinea pig chow; ad-libitum
- Water: Medicated water containing 4% sulfaethoxypyridazine for 3 days and non - medicated water thereafter; ad-libitum
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
No details on environmental conditions were provided in the study report.

IN-LIFE DATES: Not reported
Route:
epicutaneous, occlusive
Vehicle:
other: Distilled water
Concentration / amount:
0.5 mL undiluted test substance for the first 2 induction exposures and 50% aqueous solution of test substance for the third induction exposure (due to severe irritation observed in the animals during first 2 inductions)
Day(s)/duration:
Once a week for 3 weeks
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: Distilled water
Concentration / amount:
0.5 mL of 10% aqueous solution of the test substance
Day(s)/duration:
Once, after 2 weeks of last induction
No. of animals per dose:
Treatment group: 20 guinea pigs
Control group: 10 guinea pigs
Details on study design:
RANGE FINDING TESTS FOR PRIMARY CHALLENGE PHASE: Yes, range finding study was conducted in order to determine the highest non-irritating concentration which could be applied for the primary challenge.During the induction phase of the study, 4 additional animals were treated with a single application of 5, 10, 20 and 40% aqueous solution of the test substance on the clipped backs. Patches were applied in a method similar to the induction exposure. On the day following application, the clipped areas were depilated with ZipR (Jean Jordeau, Inc., Dist., New York). The depilatory was allowed to remain on the sites for 15 - 30 minutes and was then washed off with warm (approx. 37⁰C) tap water. The test sites were scored for irritation 3-5 hours later.

Further details about skin reactions in range finding study are present in the table 1 of "Any other information of results inc. tables" section.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: 6 hours
- Test groups: One test group including 20 animals
- Control group: Control animals were not treated during induction phase
- Site: Upper left quadrant of the backs of the test animals, clipped free of hair with electric clipper on the day before exposure.
-Concentrations: 0.5 mL undiluted test substance (for first 2 induction exposure) and 50% aqueous solution (for third induction exposure)
-Test procedure: Patches were applied using Duke Elastopatch coverlet with 3/4 x 1-inch webril swatch moistened with 0.5 mL undiluted test substance. The guinea pigs were placed in restrainers and rubber dental damming was placed over the animal’s backs and secured to the restrainers with clips. After the 6 hours exposure period, the patches were removed, and the animals were returned to their cages. Due to severe irritation noted following the second induction, the third induction application was conducted using a 50% aqueous solution of test substance.
- Frequency of applications: Once in a week
- Duration: 3 weeks

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 2 week after last induction exposure
- Exposure period: 6 hours
- Test group: One test group including 20 animals
- Control group: One control group including 10 animals
- Site: Lower left quadrant of the backs of test and control animals, clipped free of hair
- Concentrations: 0.5 mL of 10% aqueous solution of test substance
- Evaluation (hr after challenge): 24 and 48 hours after challenge exposure.
Challenge controls:
10 challenge control animals (previously unexposed) were treated with 0.5 mL of 10% aqueous solution of the test substance
Positive control substance(s):
no
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
0.5 mL of 10% aqueous solution
No. with + reactions:
2
Total no. in group:
20
Clinical observations:
2 animals with sensitization grade of 1 (Slight confluent or moderate patchy erythema); 11 animals with grade ± (slight patchy erythema) were observed.
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0.5 mL of 10% aqueous solution
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin sensitization response was observed and 5 animals with grade ± (slight patchy erythema) were observed.
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
0.5 mL of 10% aqueous solution
No. with + reactions:
2
Total no. in group:
20
Clinical observations:
2 animals with sensitization grade of 1 (Slight confluent or moderate patchy erythema); 14 animals with grade ± (slight patchy erythema) were observed.
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0.5 mL of 10% aqueous solution
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No skin sensitization response was observed and 6 animals with grade ± (slight patchy erythema) were observed.
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Remarks on result:
not measured/tested

Table 1: Irritation scores for range finding experiment (Study#13231)

S.no 40% application of test substance at site 1
20% application of test substance at site 2
10% application of test substance at site 3
5% application of test substance at site 4
1 ± ± ± 0
2 0 0 0 0
3 ± ± 0 0
4 ± ± ± 0

Table 2: Hypersensitivity scores for guinea pigs after primary challenge application of 10% aqueous solution of Monoethanolamine (MEA) (Study#13231)

Group

Guinea Pig No.

Reading

 

 

 

24 hours

48 hours

Test substance treated animals

1

±

±

2

1

1

3

±

±

4

±

±

5

±

±

6

0

0

7

0

0

8

±

±

9

0

±

10

0

±

11

1

1

12

±

±

13

±

±

14

0

0

15

±

±

16

±

±

17

±

±

18

0

±

19

0

0

20

±

±

Control animals

21

±

±

22

0

0

23

0

±

24

0

0

25

±

±

26

±

±

27

0

0

28

±

±

29

±

±

30

0

0

Interpretation of results:
GHS criteria not met
Remarks:
(2/20 animals exhibited weak degree of hypersensitivity reaction. However in general, test substance was considered to produce no positive reaction in test or control group animals)
Conclusions:
Monoethanolamine (MEA; purity: 97%) was determined to be non-sensitizing in delayed contact hypersensitivity (Buehler) test when applied topically to Hartley albino guinea pigs.
Executive summary:

The skin sensitization potential of Monoethanolamine (MEA; purity: 97%) was determined in Hartley albino guinea pigs following a method comparable to OECD Guideline 406 (Skin Sensitization).

A total of 30 Hartley albino guinea pigs (source: Sweetwater farms) weighing 350 - 400 g were used in this study. Animals were fed Purina guinea pig chow and non-medicated water, ad libitum and acclimated in laboratory conditions for 5 days prior to initiation of treatment.

A group of 20 animals (treatment group) was subjected to topical induction exposures (once in a week for a three week period) with 0.5 mL of undiluted test substance for the first 2 induction exposure. Due to severe irritation noted following the second induction, the third exposure was conducted using a 50% aqueous solution of test substance. 10 animals without induction exposure served as control group.

Test patches were applied to clipped upper left quadrant on the backs of test animals, using Duke Elastopatch coverlet with ¾ x 1-inch webril swatch moistened with the test substance (at above mentioned concentrations). The animals were placed in restrainers for 6 hours exposure period, thereafter, the patches were removed and the animals were returned to their cages. The procedure was repeated at the same site once a week for the next 2 weeks, for total of three exposures. After last induction exposure, animals were left untreated until primary challenge was applied.

Two weeks after the last induction application, treatment and control group animals were subjected to primary challenge application of 10% aqueous test solution on lower left quadrant, in manner similar to the induction exposure. Day following challenge application, the sites were depilated and scored within 3-5 hours (24 hours reading). The sites were scored again for a 48 hours reading (without additional depilation).

Following the primary challenge application, reactions noted at both time intervals (i.e. 24-and 48-hours)indicated weak degree of hypersensitivity in two animals. However, as concluded by the author, test substance was considered to produce no positive reaction in test or control group animals.

Based on the results, Monoethanolamine (MEA; purity: 97%) was determined to be non-sensitizing in delayed contact hypersensitivity (Buehler) test when applied topically to Hartley albino guinea pigs.

This skin sensitization study is classified as acceptable, and satisfies the guideline requirements of OECD

406 method.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

Skin sensitisation

 

Study 1 (C10-13 LAS):  

  

A skin sensitisation study was conducted with C10-13 LAS, sodium salt according to OECD Guideline 406, under GLP. 10 male and 10 female guinea pigs were given intradermal injections of 25% test solution. Control animals (5 male and 5 female) were given injections of vehicle only. One week later, a second induction was done by dermal exposure to 25% test solution for 24 h. On Day 21, the challenge exposure was performed epidermally with 12.5% test concentration for an exposure period of 24 h. Observations were made at 48 and 72 h after the start of exposure. No positive reactions were noted. Under the study conditions, the test substance was not sensitizing (RBM, 1985). 

  

Study 2 (MEA):  

     

A skin sensitisation study was conducted with monoethanolamine (MEA) according to guinea pig maximization protocol. 15 Dunkin-Hartley guinea pigs were treated with MEA at 0.6 and 10.3% in water for intradermal and epicutaneous induction, respectively. Before the epicutaneous induction, the animals were treated topically with 10% sodium dodecyl sulphate. The animals were then challenged with 4.1, 2.05 and 0.41% of MEA. After challenge with 4.1, 2.05 and 0.41% of MEA, 3/15, 2/15 and 3/15 animals reacted positively after 72 h. Two out of 15 animals showed a reaction to the vehicle. The test with monoethanolamine was performed twice. In the 2nd test, only 1 and 2 animals showed a reaction to 4.1 and 2.05% MEA respectively, but none of the animals reacted to 0.41%. Since no statistically significant difference between actively induced animals and control animals was observed, MEA was not considered to be sensitising to skin (Wahlberg, 1996).

  

Study 3 (MEA):  

     

A skin sensitisation study was conducted with monoethanolamine (MEA) in Hartley albino guinea pigs following a method comparable to OECD Guideline 406 (Buehler test protocol). A total of 30 guinea pigs were used in this study. A group of 20 animals was subjected to topical induction exposure (once per week for 3 weeks) with 0.5 mL of undiluted test substance for the first 2 induction exposure. Due to severe irritation noted following the second induction, the third exposure was conducted using a 50% aqueous solution of test substance. 10 animals without induction exposure served as control group. Two weeks after the last induction application, treatment and control group animals were subjected to primary challenge application of 10% aqueous test solution. 24 h and 48 h after exposure , the skin responses were observed/scored. Reactions were observed at both time intervals and indicated weak degree of hypersensitivity in two animals. Under the study conditions, MEA was not sensitising to skin (Young, 1975).

  

Study 4 (MEA):  

     

A skin sensitisation study was conducted with monoethanolamine (MEA) in Hartley albino guinea pigs following a method comparable to OECD Guideline 406 (Buehler test protocol). A total of 30 Hartley albino guinea pigs were used in this study. A group of 20 animals was subjected to topical induction exposure (once per week for 3 weeks) for 6 h with 0.4 mL of 10% test substance for the first 2 induction exposure. 10 animals without induction exposure served as control group. After 2 weeks rest period from the last induction exposure, the test and primary challenge control animals were challenged at a fresh site with 0.4 mL of 10% test substance. Approximately 18 h after the primary challenge, test sites were depilated and were scored. The sites were scored again after 24 h. The responses in both test and control groups were comparable. Under the study conditions, MEA was not sensitising to skin (Muller and Calvin, 1981).

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on the results of in vivo skin sensitisation studies in guinea pigs and mice, MEA-LAS does not warrant classification for this endpoint according to EU CLP (1272/2008/EC) criteria.