Tetrasodium 3,3'-[carbonylbis[imino(5-methoxy-2-methyl-4,1-phenylene)azo]]bis(naphthalene-1,5-disulphonate)

Endpoint summary

Description of key information

In an LLNA test 4 female mice/concentration were dermally (back of the ears) exposed to the substance at 0, 5, 10 and 25% during 3 consecutive days. After injection with ³H-thymidine, 3HTdR incorporation was measured in a β-scintillation counter in cell suspensions of pooled lymphnodes (per concentration). The EC3 calculated from the stimulation indices was 23.6%. The substance is considered sensitizing to the skin.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08 March 2017 to 28 March 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

contract for this study was signed in August 2016

Qualifier:

according to guideline

Guideline:

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

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA/Ca

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Envigo RMS B.V., Inc, Postbus 6174, 5960 AD Horst / The Netherlands
- Strain: CBA/CaOlaHsd
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 8-9 weeks
- Weight at study initiation: 17.0 - 19.9 g
- Housing: per dosing group in Makrolon Type III with wire mesh top
- Diet: 2018C Teklad Global 18% protein rodent diet ad libitum
- Drinkng water: tap water ad libitum
- Acclimation period: at least 5 days
- Indication of any skin lesions: not mentioned

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C
- Humidity (%): 45-65%
- Air changes (per hr): not indicated
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

other: ethanol/water (3/7 v/v)

Concentration:

5, 10, and 25 %

No. of animals per dose:

4 females/concentration

Details on study design:

PRE-SCREEN TESTS:
- Compound solubility: max solubility 25%
- Irritation: no signs of irritation (1 female/concentration at 10 and 25%)
- Systemic toxicity: non observed
- Ear thickness measurements: no treatment related effects
- Erythema scores: max score : 0 (Draize)

MAIN STUDY: at 5, 10 and 25%

TREATMENT PREPARATION AND ADMINISTRATION:
Test substance or vehicle (25 µL/ear/day) was spread over the entire dorsal surface (ca 8 mm) of each ear once daily for three consecutive days. On day 6 250 µL of phosphate-buffered saline containing 20.3 µCi of 3H-methyl thymidine was injected via the tail vein. Five hours thereafter mice were euthanized and lymphnodes were harvested and pooled (per dose group). Single cell suspensions of pooled lymphnodes were prepared and, after incubation in 5 % trichloroacetic acid for 18 hours at 4 °C, the 3HTdR incorporation was then measured in a β-scintillation counter.

Positive control substance(s):

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

Statistics:

NA

Positive control results:

--> periodically investigated SI (25% 11.8; EC3 8.2%)

Key result

Parameter:

SI

Value:

2.07

Test group / Remarks:

5%

Key result

Parameter:

SI

Value:

1.41

Test group / Remarks:

10%

Key result

Parameter:

SI

Value:

3.17

Test group / Remarks:

25%

Key result

Parameter:

EC3

Value:

23.6

Remarks on result:

other: dose response is not clear

Cellular proliferation data / Observations:

CLINICAL OBSERVATIONS: none observed
BODY WEIGHTS: within normal ranges

Test item concentration %	Group	Measurement DPM	Calculation			Result
			DPM-BG^a)	number of lymph nodes	DPM per lymph node^b)	S.I.
---	BG I	17	--	--	--	--
---	BG II	19	--	--	--	--
0	1	3059	3041	8	380.1	1.00
5	2	6310	6292	8	786.5	2.07
10	3	4317	4299	8	537.4	1.41
25	4	9655	9637	8	1204.6	3.17

1 = Control Group

2-4 = Test Group

^a)= The mean value was taken from the figures BG I and BG II (BG = back ground)

^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

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

The substance is considered to be sensitizing to the skin

Executive summary:

In an LLNA test 4 female mice/concentration were dermally (back of the ears) exposed to the substance at 0, 5, 10 and 25% during 3 consecutaive days. After injection with ³H-thymidine, 3HTdR incorporation was measured in a β-scintillation counter in cell suspensions of pooled lymphnodes (per concentration). The EC3 calculated from the stimulation indices was 23.6%. The substance is considered sensitizing to the skin.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the available information the substance needs to be classified as sensitizing to the skin category 1B according to Regulation (EC) No 1272/2008.