Cysteine 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:

2016-03-16 - 2016-04-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: Skinethic skin irritation test -42bis Standard operating procedure (SOP) 2009

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

L-Cysteine Hydrochloride Monohydrate

IUPAC Name:

L-Cysteine Hydrochloride Monohydrate

Test material form:

solid: crystalline

Details on test material:

- Name of test material (as cited in study report): L-Cysteine Hydrochloride Monohydrate
- Molecular formula (if other than submission substance): C3H8O2NSCIxH2O
- Molecular weight (if other than submission substance): 175.64
- Analytical purity: 99,97 %
- Batch: 57121771
- Expiry Date: 2013-08-01
- Stability under test conditions: not known.

IN ACCORDANCE WITH ARTICLE 2(7)(b) and Annex V (6), REACH the L-Cysteine hydrochloride is registered (hydrate free
form). L-Cysteine hydrochloride monohydrate (CAS 7048-04-6) is manufactured and imported and was used for testing.

Specific details on test material used for the study:

Designation: Art. 102735
Batch: K47440335
Assay: 100.3%
(iodometric, calc. on
dried substance)
Appearance: White to almost white crystalline powder or colorless crystals
Minimum shelf life: January 31, 2018
Storage: Tightly closed, dark at room temperature (15 to 25°C)

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

foreskin from a single donor

Justification for test system used:

standard model

Vehicle:

unchanged (no vehicle)

Remarks:

No vehicle used in this study; The test item was applied neat to the tissues.

Details on test system:

CELL CULTURE
- Supplier: EpiSkin/SkinEthic Laboratories, Lyon, France)
- Source: human keratinocytes cultured on a polycarbonate filter in conditions which permit their terminal differentiation
- Format: 24 well plate
- Batch: 16-RHE-025
- Expires: 2016-03-21

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment: room temperature
- Temperature of post-treatment incubation: 37°C

REMOVAL OF TEST MATERIAL AND CONTROL
After the end of the treatment interval, the residual test item was removed immediately by gently rinsing with a minimum volume of 25 mL DPBS using a pipette. Excess DPBS was removed by gently shaking the inserts and blotting the bottom with blotting paper.

Control samples:

yes, concurrent negative control

Amount/concentration applied:

TEST MATERIAL
- Amount applied: 16 mg per tissue

NEGATIVE CONTROL
- Amount applied: 16 µL per tissue (Dulbecco`s Phosphate-Buffered Saline)

POSITIVE CONTROL
- Amount applied: 16 µL per tissue
- Concentration: 5% aqueous solution of sodium dodecyl sulfate in deionised water

Duration of treatment / exposure:

42 min (± 1 minute)

Duration of post-treatment incubation (if applicable):

42 hours (± 1 hour)

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Experiment 1 / Run 1

Value:

80.96

Vehicle controls validity:

not applicable

Remarks:

The test item was applied neat to the tissues

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: none
- Direct-MTT reduction: none
- Colour interference with MTT: none

ACCEPTANCE OF RESULTS:
Acceptability of the Quality Control Data of the Skin Model with Reference to Historical Batch Data:
The negative control OD values were 1.575, 1.555 and 1.698 and, thus, in the range of ≥0.8 and ≤3.0.

Acceptability of the Positive and Negative Control:
After treatment with the negative control (DPBS-buffer) the mean OD was 1.609 (standard deviation: 4.84%) and, thus, higher than the historically established boundary of 1.436.
After treatment with the positive control (5% aqueous solution of sodium dodecyl sulfate) the mean viability value was 1.28% (standard deviation: 13.56%) and, thus, lower than the historically established boundary of 3.28%.
The standard deviation of the negative control and the positive control was ≤18%, respectively.

Test Substance Data Acceptance Criteria:
The standard deviation of the three tissues treated with the test item was 15.00% and, thus, ≤18%.

Therefore, the study fulfilled the validity criteria.

Any other information on results incl. tables

Group	Time / [min]	Mean OD	Mean Relative viability / [%]
Negative Control	42	1.609	100
Positive Control	42	0.021	1.28
Test Material	42	1.303	80.96

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

UN GHS: No Caterory (according to OECD TG 439)

Conclusions:

This study was performed according to GLP and the methods applied are fully compliant with OECD TG 439. Under the conditions of the present study, the test item Art. 102735 is not considered to possess an irritant potential to skin (UN GHS: No Category).

Executive summary:

This study was performed according to GLP and the methods applied are fully compliant with OECD TG 439. Under the conditions of the present study, the test item Art. 102735 is not considered to possess an irritant potential to skin (UN GHS: No Category).