Registration Dossier

Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
13 Apr - 29 Apr 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD guideline conform GLP study.

Data source

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

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymphnode assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Purity: 99.8% (m/m)
Stability in solvent: 24 hours in water, propylene glycol, DMSO, DMF, acetone:olive oil (4+1), and methyl ethyl ketone
Storage: At room temperature

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories B.V., Postbus 6174, 5960 AD Horst / The Netherlands
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 15 - 25 g
- Housing:single caging
- Diet (e.g. ad libitum): pelleted standard diet (Harlan Laboratories GmbH, 33178 Borchen), ad libidum
- Water (e.g. ad libitum): tap water, (Gemeindewerke, 64380 Rossdorf), ad libitum
- Acclimation period: At least 5 days prior to the start of dosing under test conditions after health examination. Only animals without any visible signs of illness will be used for the study

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 + 2°C
- Humidity (%): 45-65%
- Photoperiod (hrs dark / hrs light): artificial light 6:00 a.m. - 6:00 p.m.

Study design: in vivo (LLNA)

Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
25, 50, and 100%
No. of animals per dose:
4
Details on study design:
In order to study a possible allergenic potential of Diethylenglycol EM, three groups each of four female mice were treated with different concentrations of the test item by topical application at the dorsum of each ear (left and right) on three consecutive days. A control group of four mice was treated with the vehicle only. Five days after the first topical application, the mice were intravenously injected into a tail vein with radio-labelled thymidine (3H-methyl thymidine). Approximately five hours after intravenous injection, the mice were sacrificed and the draining auricular lymph nodes excised and pooled per group. Single cell suspensions of lymph node cells were prepared from pooled lymph nodes, which were subsequently washed and incubated with trichloroacetic acid overnight. The proliferative capacity of pooled lymph node cells was determined by the incorporation of 3H-methyl thymidine measured in a -scintillation counter.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
The mean values and standard deviations were calculated in the body weight tables.

Results and discussion

Positive control results:
Experiment performend in November 2009, 5, 10, and 25% alpha-Hexylcinnamaldehyde yielded a S.I. of 1.78, 2.54, and 4.88, respectively. The EC3 value calculated was 12.9%

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: see table below
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: see table below

Any other information on results incl. tables

Test item concentration % (w/v)

Group

Measurement DPM

Calculation

Result

DPM-BGa)

number of lymph nodes

DPM per lymph nodeb)

S.I.

---

BG I

16

---

---

---

---

---

BG II

15

---

---

---

---

---

1

4826

4811

8

601.3

 

25

2

3520

3505

8

438.1

0.73

50

3

4984

4969

8

621.1

1.03

100

4

3345

3330

8

416.2

0.69

BG = Background (1 ml 5% trichloroacetic acid) in duplicate 1 = Control Group 2-4 = Test Group S.I. = Stimulation Index

a) = The mean value was taken from the figures BG I and BG II b) = Since the lymph nodes of the animals of a dose group were pooled, DPM/node was determined by dividing the measured value by the number of lymph nodes pooled

The EC3 value could not be calculated, since all S.I.´s are below 3.

Viability / Mortality: No deaths occurred during the study period.

Clinical Signs: No symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period.

Body Weights: The body weight of the animals, recorded prior to the first application and prior to treatment with3HTdR, was within the range commonly recorded for animals of this strain and age.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
The test item Diethylenglycol EM was not a skin sensitiser under the described conditions.
Executive summary:

Triethylene glycol dimethyl ether and Diethylene glycol methyl ethyl ether, which is tested for its sensitising potential, belong to the glycol ether family. These substances have been demonstrated to be very similar in structure, physical/chemical properties and the toxicological profile. Due to the fact that Triethylene glycol dimethyl ether and Diethylene glycol methyl ethyl ether have nearly the same chemical structure (especialy with reference to the functional groups):

1. Triethylene glycol dimethyl ether:H3C-O-CH2-CH2-O-CH2 -CH2 -O-CH2 -CH2 -O-CH3

2. Diethylene glycol methyl ethyl ether:H3C-O-CH2-CH2-O-CH2-CH2-O-CH2-CH3

the same mode of interaction with living cells and tissue is expected. Therefore, a read-across from Triethylene glycol dimethyl ether to data obtained with Diethylene glycol methyl ethyl ether is scientifically justified.

The present study (Vogel 2010) analyses the sensitising potential of Diethylenglycol EM

Three groups each of four female mice were treated daily with the test item at concentrations of 25, 50, and 100% (w/v) in acetone:olive oil (4+1) by topical application to the dorsum of each ear (left and right) for three consecutive days. A control group of four mice was treated with the vehicle (acetone:olive oil (4+1)) only. Five days after the first topical application the mice were injected intravenously into a tail vein with radio-labelled thymidine (3H-methyl thymidine). Approximately five hours after intravenous injection, the mice were sacrificed, the draining auricular lymph nodes excised and pooled per group. Single cell suspensions of lymph node cells were prepared from pooled lymph nodes, which were subsequently washed and incubated with trichloroacetic acid overnight. The proliferative capacity of pooled lymph node cells was determined by the incorporation of3H-methyl thymidine measured in ab-scintillation counter.

All treated animals survived the scheduled study period and no signs of toxicity were observed.

A test item is regarded as a sensitiser in the LLNA if the exposure to one or more test concentration resulted in 3-fold or greater increase in incorporation of3HTdR compared with concurrent controls, as indicated by the Stimulation Index (S.I.). The estimated concentration of test item required to produce a S.I. of 3 is referred to as the EC3 value.

In this study Stimulation Indices of 0.73, 1.03, and 0.69 were determined with the test item at concentrations of 25, 50, and 100% in acetone:olive oil (4+1). The EC3 value could not be calculated, since none of the tested concentrations induced an S.I. greater than 3.