Registration Dossier

Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from 21 May 2010 to 28 July 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Compliant to GLP and testing guideline; adequate coherence between data, comments and conclusions.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material Sec-Butyl aminoethanol
- Physical state: colorless liquid
- Analytical purity: 99.73%
- Impurities (identity and concentrations): EAC =0.066%, sum of unknown=0.171%, sum of organics =0.237%, water =0.035%
- Lot/batch No.: A1V68M010101
- Expiration date of the lot/batch: January 2011
- Storage conditions of test material: at room temperature and protected from light.


In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Breeder : Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: the animals of the preliminary test were approximately 11 weeks old and the animals of the main test were approximately
9 weeks old
- Weight at study initiation: 21.8 +/- 0.9 g
- Housing: the animals were housed individually in disposable crystal polystyrene cages (22.00 cm x 8.50 cm x 8.00 cm)
- Diet (e.g. ad libitum): free access to SSNIFF R/M-H pelleted maintenance diet
- Water (e.g. ad libitum): tap water (filtered using a 0.22 micron filter)
- Acclimation period: at least 5 days before the beginning of the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2°C
- Humidity (%): 50 +/- 20%
- Air changes (per hr): approximately 12 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12 h/12 h (7:00 - 19:00)

IN-LIFE DATES: From: 03 June 2010 To: 28 July 2010

Study design: in vivo (LLNA)

Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
0.25, 0.5, 1, 2.5 and 5%.
No. of animals per dose:
4 females per dose.
Details on study design:
RANGE FINDING TESTS:
- Compound solubility: yes at up to 50% oin AOO 4/1 v/v
- Irritation: corrosive so it was only tested at up to 50%; erythema and increased ear thickness at concentrations of 10% and above, skin dryness at 5%, the highest concentration retained for the main test was therefore 5%.
- Lymph node proliferation response: not performed

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA, proliferation of lymphocytes in the lymph node draining the application site was measured by incorporation of
tritiated methyl thymidine
- Criteria used to consider a positive response: when the SI for a dose group is ≥ 3. Other relevant criteria such as cellularity, radioactivity levels and ear thickness were also taken into account for the interpretation of results.

TREATMENT PREPARATION AND ADMINISTRATION:
On days 1, 2 and 3, a dose-volume of 25 μL of the control or dosage form preparations was applied to the dorsal surface of both ears, using an adjustable pipette fitted with a plastic tip. In order to avoid licking and to ensure an optimized application of the test materials, the animals were placed under light isoflurane anesthezia during the administration. No massage was performed but the tip was used to spread the preparation over the application sites. No rinsing was performed between each application.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

Positive control results:
HCA at the concentration of 25%: a significant lymphoproliferation was noted. The study was considered valid.

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: SI (pooled): 1.30, 1.09, 1.08, 2.06, 12.2 and 10.9 at 0.25, 0.5, 1, 2.5 and 5% and for HCA, respectively. A significant lymphoproliferation was noted at the concentration of 5%. EC3 value: 2.7%.
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: DPM per node (pooled): 217, 281, 236, 234, 447, 2651 and 2371 at 0 (vehicle), 0.25, 0.5, 1, 2.5 and 5% and for HCA, respectively. A significant lymphoproliferation was noted at the concentration of 5%.

Applicant's summary and conclusion

Interpretation of results:
other: Skin sensitizer category 1B
Remarks:
Criteria used for interpretation of results: EU
Conclusions:
The test item Sec-Butyl aminoethanol(batch No. A1V68M010101) induced delayed contact hypersensitivity in the murine Local Lymph Node Assay.
According to the EC3 value obtained in this experiment, the test item ASec-Butyl aminoethanol should be considered as a moderate sensitizer.
Executive summary:

The potential of 2-[(1-methylpropyl)amino]ethanol was to evaluate to induce delayed contact hypersensitivity using the murine Local Lymph Node Assay (LLNA). Evaluation of local irritation was also carried out in parallel. This study was conducted in compliance with the principles of Good Laboratory Practice Regulations. A preliminary test was first performed in order to define the concentrations of test item to be used in the main test. In the main test, twenty eight female CBA/J mice were allocated to seven groups, five treated groups of four animals receiving 2-[(1-methylpropyl)amino]ethanol at the concentration of 0.25, 0.5, 1, 2.5 and 5% in a mixture acetone/olive oil (4/1; v/v) (vehicle), one negative control group of four animals receiving the vehicle, and one positive control group of four animals receiving the reference item, alpha-hexylcinnamaldehyde (HCA), a moderate sensitizer, at the concentration of 25% in the vehicle. During the induction phase, the test item, vehicle or reference item was applied over the ears (25 µL per ear) for 3 consecutive days (days 1, 2 and 3). After 2 days of resting, the proliferation of lymphocytes in the lymph node draining the application site was measured by incorporation of tritiated methyl thymidine (day 6). The obtained values were used to calculate Stimulation Indices (SI). The irritant potential of the test item was assessed in parallel by measurement of ear thickness on days 1, 2, 3 and 6. 2-[(1-methylpropyl)amino]ethanol was soluble in the first recommended vehicle, acetone/olive oil (4/1, v/v). A solution was obtained at the maximum tested concentration of 50%. Since the liquid test item is corrosive it was not used at the concentration of 100%. Consequently, the concentrations selected for the preliminary test were 5, 10, 25 and 50%. Since the test item was irritant in the preliminary test at the concentrations ≥ 10%, the highest tested concentration retained for the main test was 5%. Neither mortality nor clinical signs were observed during the study. No cutaneous reactions and no notable increase in ear thickness were observed in the animals of the treated groups. A significant lymphoproliferation was noted in the positive control group given HCA at 25%. The study was therefore considered valid. A significant lymphoproliferation was noted at the concentration of 5%.

 

The results are presented in the following table:

 

Treatment

Concentration

(%)

Irritation level

Stimulation Index

(SI)

Test item

0.25

non-irritant

1.30

Test item

0.5

non-irritant

1.09

Test item

1

non-irritant

1.08

Test item

2.5

non-irritant

2.06

Test item

5

non-irritant

12.22

HCA

25

-

10.93

In the absence of local irritation, the significant lymphoproliferative response observed was attributed to delayed contact hypersensitivity. The EC3value for the test item 2-[(1-methylpropyl)amino]ethanol is equal to 2.7%.

2-[(1-methylpropyl)amino]ethanol induced delayed contact hypersensitivity in the murine Local Lymph Node Assay. According to the EC3value obtained in this experiment, 2-[(1-methylpropyl)amino]ethanolshould be considered as a moderate sensitizer.