Disodium disilicate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to other 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:

yes

Remarks:

positive control: p-phenylenediamine

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:

Disodium disilicate

EC Number:

237-623-4

EC Name:

Disodium disilicate

Cas Number:

13870-28-5

Molecular formula:

Na2Si2O5

IUPAC Name:

disodium disilicate

Details on test material:

- Name of test material (as cited in study report): Layered Silicate SKS-6
- Physical state: solid, powder
- Colour: white
- Storage condition of test material: room temperature

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/CaOlaHsD

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Winkelmann, D-33178 Borchen, Germany
- Age at study initiation: 8-9 weeks
- Weight at study initiation: 18 - 22 g

Study design: in vivo (LLNA)

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

6.25%, 12.5% and 25%

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: maximum 25%
- Irritation: no


MAIN STUDY:
- Evaluation:
Proliferative response of lymph node cells:
DPM/NODE = number of radioactive disintegrations per minute per lymph node;
STIMULATION INDEX = ratio of 3H-methyl thymidine - incorporation into lymph node cells of test group animals relative to that recorded for control group animals. Background values were subtracted.
EC3 values are determined by linear interpolation {EC3=c+[(3-d)/(b-d)]x(a-c)}, between two points of the stimulation indices axis, one above (a,b) and one below (c,d) the stimulation index of three. If all measured points are above or below the stimulation index of three, no EC3 value can be stated.

- Criteria used to consider a positive response: Stimulation Index ? 3.0

Positive control substance(s):

other: p-phenylenediamine 1%

Statistics:

NA

Results and discussion

Positive control results:

Mean values (SD): DPM: 14552.2 (2997.6), DPM/node: 7265.3 (1498.8), Stimulation Index: 12.0 (2.5)

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: c = 6.25%: SI = 0.7 ±0.3 c = 12.5%; SI = 0.6 ± 0.1 c = 25%; SI = 0.7 ± 0.2

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: 6.25%; mean values (SD): DPM: 822.8 (393.6); DPM/node: 384.7 (196.8) 12.5%; mean values (SD): DPM: 748.0 (117.4); DPM/node: 347.3 (58.7) 25%; mean values (SD): DPM: 834.0 (221.4); DPM/node: 390.3 (110.7)

Any other information on results incl. tables

Radioactive Determination of the Test Substance Groups

 

POS	CPM	Test Item	Conc. [%]	Animal number	DPM	DPM- mean back- ground	DPM/ Node	Stimulation Index
18	457.0	Negative Control		16	950.0	896.6	448.3
19	701.0			17	1467.0	1413.6	706.8
20	486.0			18	1017.0	963.6	481.8
21	444.0			19	931.0	877.6	438.8
22	860.0			20	1795.0	1741.6	870.8
MV	589.6			MV	1232.0	1178.6	589.3	1.0
SD	164.3			SD	343.1	343.1	171.5
61	340.0	disodium disilicate (delta-crystalline)	6.25	1	722.0	668.6	334.3	0.6
62	67.0			2	143.0	89.6	44.8	0.1
63	438.0			3	927.0	873.6	436.8	0.7
64	626.0			4	1338.0	1284.6	642.3	1.1
65	469.0			5	984.0	930.6	465.3	0.8
MV	388.0			MV	822.8	769.4	384.7	0.7
SD	185.0			SD	393.6	393.6	196.8	0.3
66	386.0	disodium disilicate (delta-crystalline)	12.5	6	820.0	766.6	383.3	0.7
67	263.0			7	553.0	499.6	249.8	0.4
68	406.0			8	856.0	802.6	401.3	0.7
69	1275.0*			9
70	363.0			10	763.0	709.6	354.8	0.6
MV	354.5			MV	748.0	694.6	347.3	0.6
SD	55.0			SD	117.4	117.4	58.7	0.1
73	576.0	disodium disilicate (delta-crystalline)	25	11	1199.0	1145.6	572.8	1.0
74	335.0			12	704.0	650.6	325.3	0.6
75	341.0			13	719.0	665.6	332.8	0.6
76	277.0			14	581.0	527.6	263.8	0.4
77	463.0			15	967.0	913.6	456.8	0.8
MV	398.4			MV	834.0	780.6	390.3	0.7
SD	107.5			SD	221.4	221.4	110.7	0.2
90	23.0	Background Szinti and TCA			47.0
91	27.0				55.0
92	29.0				60.0
93	29.0				61.0
94	21.0				44.0
MV	25.8			MV	53.4	0.0	0.0	0.0
SD	3.2			SD	6.8

*outlier failed Grubbs, Nalimov,

 

POS = position in counter; CPM = counts per minute; Conc. = concentration;

DPM = disintegrations per minute; SD = standard deviation; MV = mean value;

Szinti = scintillation fluid; TCA = trichloroacetic acid

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

The test substance does not meet the criteria for EU or GHS-EU classification.

Executive summary:

Materials and methods

Based on the results of a preliminary test the test item was assessed for sensitising properties at concentrations of 0 (vehicle only), 6.25%, 12.5% and 25% (v/v) in an LLNA according to OECD 429. The study was performed on female CBA/CaOlaHsd mice; 5 animals were used per group. Acetone/olive oil (4:1 (v/v)) was used as vehicle. General clinical signs and mortality as well as bodyweight development were monitored during the study.

Results and Discussion

At the daily clinical observation the animals did not show any visible clinical symptoms and no case of mortality were observed. Body weight development was unaffected.

None of the three tested concentrations of the test item reached the stimulation index of 3. The stimulation indices were: at a concentration of 6.25% = 0.7; at a concentration of 12.5% = 0.6 and at a concentration of 25% = 0.7. The EC3 value could not be calculated.

The test item is regarded to have no skin sensitising properties.