magnesium sodium fluoride silicate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011-07-27 to 2011-08-23

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

2010-07-22

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EpiSkinTM SOP, Version 1.8, ECVAM Skin Irritation Validation Study: Validation of the EpiSkinTM test method 15 min-42 hours for the predication of acute skin irritation of chemicals

Version / remarks:

February 2009

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

442-650-1

EC Name:

-

Cas Number:

56450-90-9

Molecular formula:

F4Mg5Na2O20Si8

IUPAC Name:

silanedione hydrofluoride magnesium dihydride sodium hydride

Test material form:

solid: particulate/powder

Details on test material:

One sample of Sodium Magnesium Fluoride Silicate, Lot No. 91107
EINECS# 442-650-1
CAS# 56450-90-9
Sample submission date: 16.11.2009

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Topy Indsutries Ltd. / 91108
- Expiration date of the lot/batch: 2014-11-20

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: soluble and stable
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: none

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: no
- Final preparation of a solid: No preparartion before administered

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

other: reconstructed epidermis units

Vehicle:

other: Direct administration but 2 ml MTT soluation (0.3 mg/mL) added. MTT: [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Thiazolyl blue

Details on test system:

Test system preparation:
After receipt of the EpiSkinTM kit, all of the epidermis units used in the study were pre-incubated in maintenance medium (provided by kit supplier) at 37 °C, 5% CO2 for at least 24 hours before dosing.

Dose of test and control substances
Before topical application, the three epidermis units for test substance were moistened with 5 µl distilled water. Each of the three epidermis units for test chemical was dosed with test substance at 10 mg and incubated at room temperature for 15 minutes
Each of the three epidermis units for positive control was dosed with positive control substance (5% SDS) at 10 µl and incubated at room temperature for 15 minutes.
Each of the three epidermis units for negative control was dosed with negative control substance (PBS) at 10 µl and incubated at room temperature for 15 minutes.

Post-treatment incubation
After treatment, all the treated epidermis units were rinsed with PBS (approximately 25 ml per unit) at room temperature, following the user manual of the EpiSkinTM –SM reconstructed epidermis kit. After rinsing with PBS solution, the treated epidermis units will be incubated at 37 oC, 5% CO2 for approximately 42 hours.

MTT assay
After 42-hour incubation, the epidermis units were transferred into assay medium with 0.3 mg/ml MTT (protected from light) and incubated at 37 oC, 5% CO2 for 3 hours as described in the user manual of the EpiSkinTM –SM reconstructed epidermis kit.
The epidermis units were dried on absorbent paper at the end of incubation. Each epidermis unit were then gently separated using biopsy punch from the collagen matrix with the aid of forceps. The separated tissues were placed into a micro tube with 500 µl of acidic isopropanol and mixed thoroughly. The micro tubes were stored at 4 °C for approximately 70 hours (over the weekend).
The solution of in the micro tubes were vortexed to homogenize the solution colour. Two 200 µl of solution from each tube was transferred into a 96-well plate. The absorbance (OD) at 570 nm was read using microplate reader.

Control samples:

yes, concurrent negative control

yes, concurrent vehicle

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 10 mg

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 10 µl

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 10 µl 5 % SDS

Duration of treatment / exposure:

15 min

Duration of post-treatment incubation (if applicable):

42 h

Number of replicates:

3 replicates of magnesium sodium fluoride silicate, positive control and negative control; 1 preplicate for test substance without MTT

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

other: mean viability

Remarks:

value is 91 % after subtracting the interference of tissue staining without MTT

Value:

91

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the above results and Global Harmonised Classification System (GHS) as wll as CLP-Regulation, magnesium sodium fluoride silicate, is considered as non-irritant to skin; the skin irritation category of the test item is Unclassified (no category).

Executive summary:

Based on the above results and Global Harmonised Classification System (GHS) as wll as CLP-Regulation, magnesium sodium fluoride silicate, is considered as non-irritant to skin; the skin irritation category of the test item is Unclassified (no category).