Dimethyl 2-aminoterephthalate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: well performed GLP and OECD guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Dimethyl 2-aminoterephthalate

EC Number:

226-364-2

EC Name:

Dimethyl 2-aminoterephthalate

Cas Number:

5372-81-6

Molecular formula:

C10H11NO4

IUPAC Name:

1,4-dimethyl 2-aminobenzene-1,4-dicarboxylate

Details on test material:

- Name of test material (as cited in study report): Amino-DMT trocken

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories
- 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), ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: At least 5 days prior to the start of dosing

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): 45-75
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

dimethylformamide

Concentration:

5, 10, and 25%
The top dose is the highest technically achievable concentration whilst avoiding systemic toxicity and excessive local irritation.

No. of animals per dose:

4

Details on study design:

In order to study a possible allergenic potential of Amino-DMT trocken, 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 lobe (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 ß-scintillation counter. After the lymph nodes have been excised, both ears of mice were punched at the apical area (Ø 8 mm corresponding to 0.5 cm2). For each animal the weight of both punches was determined.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

The mean values and standard deviations were calculated for body weights.
The ANOVA (Dunnett-test) was conducted on the ear weights to assess whether the difference is statistically significant between test item groups and negative control (vehicle) group. However, both biological and statistical significance will be considered together.

Results and discussion

Positive control results:

Experiment performend in June 2009:
5, 10, and 25% alpha-Hexylcinnamaldehyde yielded a S.I. of 1.79, 2.09, and 6.84, respectively. The EC3 value calculated was 12.9%

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: S.I. 5 %: 0.75 10 %: 1.23 25 %: 1.01

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Measured DPM Control: 4039 5 %: 3054 10 %: 4944 25 %: 4090

Any other information on results incl. tables

Test item concentration % (w/v)	Group	Measurement DPM	Calculation			Result
			DPM-BG^a)	number of lymph nodes	DPM per lymph node^b^)	S.I.
---	BG I	20	---	---	---	---
---	BG II	21	---	---	---	---
---	1	4039	4019	8	502.3
5	2	3054	3034	8	379.2	0.75
10	3	4944	4924	8	615.4	1.23
25	4	4090	4070	8	508.7	1.01

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 with ³HTdR, was within the range commonly recorded for animals of this strain and age.

EarWeights

The measured ear weights of all animals treated were recorded after necropsy. A relevant increase in ear weights was not observed.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

The test item Amino-DMT trocken was not a skin sensitiser under the described conditions.

Executive summary:

In the study the test item Amino-DMT trocken suspended in dimethylformamide was assessed for its possible contact allergenic potential . For this purpose a local lymph node assay according to OECD 429 was performed using test item concentrations of 5, 10, and 25%. The animals did not show any clinical signs during the course of the study and no cases of mortality were observed. An increase in the ear weights of the treated animals was also not observed. In this study Stimulation Indices (S.I.) of 0.75, 1.23, and 1.01 were determined with the test item at concentrations of 5, 10, and 25% in dimethylformamide, respectively. The test item Amino-DMT trocken was not a skin sensitiser in this assay.