Betaine hydrochloride

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23/01/2018-01/02/2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

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:

2015

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Version / remarks:

2009

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Betaine hydrochloride

EC Number:

209-683-1

EC Name:

Betaine hydrochloride

Cas Number:

590-46-5

Molecular formula:

C5H12NO2.Cl

IUPAC Name:

2-(trimethylazaniumyl)acetate

impurity 1

Reference substance name:

Minor constituents present in very low concentration and not affecting the hazardous properties of the substance

Molecular formula:

Traces of metals such as V, Mo, Zr, Ba, Sn, Ti

IUPAC Name:

Minor constituents present in very low concentration and not affecting the hazardous properties of the substance

impurity 2

Reference substance name:

Water

EC Number:

231-791-2

EC Name:

Water

Cas Number:

7732-18-5

Molecular formula:

H2O

IUPAC Name:

Water

Test material form:

solid: particulate/powder

Details on test material:

lot number 20161110

Specific details on test material used for the study:

batch number: 20161110
solid white powder

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

foreskin from a single donor

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: Reconstructed Human epidermis (SkinEthic RHE® model, Episkin SA, RHE/S/17)
- Tissue batch number(s): 18-RHE-006
- Production date: not reported
- Shipping date: not reported
- Delivery date: 30 January 2018
- Date of initiation of testing: 30 January 2018

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: not reported
- Temperature of post-treatment incubation (if applicable): 37°C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: 42 minutes after the test item application, the human epidermis were washed with 25 x 1 mL of DPBS (Dutscher - Batch No. 7530417).
- Observable damage in the tissue due to washing: none
- Modifications to validated SOP: none

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1.0 mg/mL
- Incubation time: 3 hours
- Spectrophotometer: ELx800 absorbance microplate reader
- Wavelength: 570 nm
- Filter: not reported
- Filter bandwidth: not reported
- Linear OD range of spectrophotometer: not reported

NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
There is no direct interaction between the test item and MTT

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test item is considered as non-irritant to skin in accordance with UN GHS No Category: if the mean percent viability after 42 minutes exposure and 42 hours of post-treatment incubation is > 50%.
- The test item is identified as requiring classification and labelling according to UN GHS (Category 2): if the mean percent tissue viability after 42 minutes exposure and 42 hours of post-treatment incubation is ≤ 50% and the result of a skin corrosion test is “non corrosive”.
- The test item is identified as requiring classification and labelling according to UN GHS (Category 2 or Category 1): if the mean percent tissue viability after 42 minutes exposure and 42 hours of post-treatment incubation is ≤ 50% and in absence of information on a skin corrosion test.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

16 mg/0.5 cm2

Duration of treatment / exposure:

42min

Duration of post-treatment incubation (if applicable):

42h

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Value:

95.4

Negative controls validity:

valid

Remarks:

mean tissue viability 100%

Positive controls validity:

valid

Remarks:

mean tissue viability 1.6%

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test item betaine hydrochloride has to be considered as Non-irritant to skin. It corresponds to UN GHS No Category.
No hazard statement or signal word is required.

Executive summary:

The aim was to evaluate the possible irritating effects of the test item betaine hydrochloride after topical application on in vitro human reconstructed epidermis (SkinEthic RHE model).

The test item was applied as supplied, during 42 minutes, at the dose of 16 mg to 3 kuvubg reconstructed human epidermis of 0.50 cm2 previously moistened with 10 microliters of distilled water. The application was followed by a rinse with 25 ml of DPBS and a 42 hours post-incubation period at 37°C, 5% CO2. Cell viability was then measured by enzymatic conversion of the vital dye MTT into a blue formazan salt that was quantitatively measured after extraction from tissues.

The mean percent viability of the treated tissues was 95.4%, versus 1.6% in the positive control (5% dodecyl sulfate)

In accordance with the regulation EC No.1272/2008, the test item betaine hydrochloride has to be considered as non-irritant to skin. It corresponds to UN GHS No Category. No hazard statement or signal word is required.