2-aminothiazol-4-acetic acid

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:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2-aminothiazol-4-acetic acid

EC Number:

249-769-6

EC Name:

2-aminothiazol-4-acetic acid

Cas Number:

29676-71-9

Molecular formula:

C5H6N2O2S

IUPAC Name:

(2-amino-1,3-thiazol-4-yl)acetic acid

Test material form:

solid: particulate/powder

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Remarks:

CBA/CaOlaHsD

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Winkelmann, 33178 Borchen, Germany
- Females (if applicable) nulliparous and non-pregnant: yes
- Microbiological status of animals, when known: Obtained from controlled full barrier breeding facility (SPF).
- Age at study initiation: 8 to 9 weeks
- Weight at study initiation: ca. 20 g
- Housing: Full barrier in an air-conditioned room. Animals housed in groups of 5 in IVC cages containing saw fibre bedding.
- Diet (e.g. ad libitum): Free access to Altromin maintenance diet.
- Water (e.g. ad libitum): Free access to tap water.
- Acclimation period: At least 5 days.
- Indication of any skin lesions: Assessed ahead of study. Animals with lesions were not used.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3°C.
- Humidity (%): 55 +/- 10%
- Air changes (per hr): At least 10
- Photoperiod (hrs dark / hrs light): artificial light (12 hours light/dark cycle)

Study design: in vivo (LLNA)

Vehicle:

dimethyl sulphoxide

Concentration:

A solubility test was initially performed to define the vehicle and maximum concentration possible. the maximum technically applicable concentration was found to be 25% in DMSO. The concentrations used in the preliminary test were 25% in DMSO. Based on the observations in the preliminary test, concentrations of 6.25, 12.5 and 25% in DMSO were used in the main test.

No. of animals per dose:

3 females used in the preliminary test (2 at 25% and one control) and 5 females per group in the main test.

Details on study design:

PRE-SCREEN TESTS:
- Compound solubility: 25% in DMSO maximum technically applicable concentration.
- Irritation: No signs of irritation at the application site were noted.
- Systemic toxicity: No signs of systemic toxicity were observed.
- Ear thickness measurements: No effects of treatment on ear thickness.
- Erythema scores: No signs of irritation.

MAIN STUDY

ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response: SI Index =/> 3 at one concentration.

TREATMENT PREPARATION AND ADMINISTRATION: The test substance was suspended in DMSO. The preparations were made immediately prior to dosing. DMSO was used as the vehicle and served as the negative contol.

Each mouse was treated by topical application of 25 µL of the selected solution onto the dorsal surface of each ear. Applications were performed once daily over three consecutive days.

Positive control substance(s):

other: P-Phenylenediamine (CAS No. 106-50-3)

Statistics:

No relevant EC3 value could be calculated.

Results and discussion

Positive control results:

The results of the positive control assay (from the most recent reliability check) showed that the test system was working adequately.

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Value:

0.3

Variability:

Individual values 0.2 to 0.4

Test group / Remarks:

6.25% in DMSO

Results 2

Parameter:

SI

Value:

0.6

Variability:

Individual values 0.6 to 0.7

Test group / Remarks:

12.5% in DMSO

Results 3

Parameter:

SI

Value:

0.3

Variability:

Individual values 0.3 to 0.4

Test group / Remarks:

25% in DMSO

Cellular proliferation data / Observations:

CELLULAR PROLIFERATION DATA: The proliferative response of lymph node cells was expressed as the number of radioactive disintergrations per minute (DPM/Node). Before DPM/Node values were calculated, background values were subtracted.

DETAILS ON STIMULATION INDEX CALCULATION: The ratio of 3H-methyl thymidine; incorporation into lymph node cells of test group animals relative to that recorded for control group animals.

EC3 CALCULATION: The EC3 value could not be calculated as all mean SI values were > 3.

CLINICAL OBSERVATIONS: All animals survived the observation period without showing clinical signs.

BODY WEIGHTS: All animals showed expected weight development.

Any other information on results incl. tables

Radioactive determination of test substance groups.

POS	CPM	Test item	Conc. (%)	Animal No.	DPM	DPM – mean background	DPM node	Stimulation index
85	4019	Control	0	16	8158	8144.4	4072.2	1
86	2506			17	5120	5106.4	2553.2
87	1176			18	2398	2384.4	1192.2
88	841			19	1726	1712.4	856.2
89	7733*			20	15908*	Nd	Nd
MV	2135.5			MV	4350.5	4336.9	2168.5
SD	1253.1			SD	2539.2	2539.2	1269.6
49	603	Test substance	6.25	1	1216	1202.4	601.2	0.3
50	616			2	1288	1274.4	637.2	0.3
51	660			3	1353	1339.4	669.7	0.3
52	490			4	1004	990.4	495.2	0.2
53	757			5	1535	1521.4	760.7	0.4
MV	625.2			MV	1279.2	1265.6	632.8	0.3
SD	86.5			SD	173.6	173.6	86.8	0
54	1296	Test substance	12.5	6	2650	2636.4	1318.2	0.6
55	1219			7	2487	2473.4	1236.7	0.6
56	272**			8	549**	Nd	Nd	Nd
57	1477			9	2993	2979.4	1489.7	0.7
58	1501			10	3093	3079.4	1539.7	0.7
MV	1373.3			MV	2805.8	2792.2	1396.1	0.6
SD	119.2			SD	246.7	246.7	123.3	0.1
61	617	Test substance	25	11	1242	1228.4	614.2	0.3
62	867			12	1772	1758.4	879.2	0.4
63	1291*			13	2646**	Nd	Nd	Nd
64	578			14	1193	1179.4	589.7	0.3
65	748			15	1522	1508.4	754.2	0.3
MV	702.5			MV	1432.3	1418.7	709.36	0.3
SD	114			SD	232.9	232.9	116.4	0.1
97	7	Background	0		14	0	0	0
98	7				15
99	8				15
101	5				10
102	7				14
MV	6.8			MV	13.6
SD	1			SD	1.9

* – outlier failed Nalimov

** – Outlier failed Grubbs, Nalimov and Dixon

POS – Position in counter

CPM – Counts per minute

DPM – Disintegrations per minute

MV – mean value

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the study results, the test substance is not expected to have skin sensitising properties in accordance with the CLP regulation (1272/2008, as amended).