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EC number: 265-025-3 | CAS number: 64704-23-0
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Skin irritation / corrosion
Administrative data
- Endpoint:
- skin corrosion: in vitro / ex vivo
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 2011-07-20 to 2011-07-29
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Guideline study from supporting substance (structural analogue)
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 011
- Report date:
- 2011
Materials and methods
Test guideline
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)
- Version / remarks:
- April 13, 2004
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
Test material
- Reference substance name:
- Cystine
- EC Number:
- 200-296-3
- EC Name:
- Cystine
- Cas Number:
- 56-89-3
- Molecular formula:
- C6H12N2O4S2
- IUPAC Name:
- cystine
- Test material form:
- solid: particulate/powder
Constituent 1
- Specific details on test material used for the study:
- SOURCE OF TEST MATERIAL
- Purity: >98.5%
- Storage condition of test material: at room temperature
In vitro test system
- Test system:
- human skin model
- Source species:
- human
- Cell type:
- non-transformed keratinocytes
- Cell source:
- other: normal, human-derived epidermal keratinocytes from EST-1000 kit from CellSystems Biotechnologievertrieb GmbH
- Source strain:
- other: human
- Details on animal used as source of test system:
- Not applicable
- Justification for test system used:
- The epidermis model (e.g. EST-1000™) is derived from human keratinocytes and consists of normal, human derived epidermal keratinocytes (NHEK) which have been cultured to form a multilayered, highly differentiated model of the human epidermis. The NHEK, which are cultured on specially prepared cell culture inserts using serum free medium, attain levels of differentiation at the cutting edge of in vitro skin technology. Ultrastructurally, the skin models closely parallel human skin.
- Vehicle:
- not specified
- Details on test system:
- RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: normal, human-derived epidermal keratinocytes (NHEK) EST-1000™ (CellSystems Biotechnologievertrieb GmbH)
This skin model consists of normal human epidermal keratinocytes (NHEK) which have been cultured to form a multilayered, highly differentiated model of the human epidermis. The NHEK are cultured on specially prepared cell culture inserts (Millicells, 10 mm). It consists of organized basal, spinous and granular layers, and a multi-layered stratum corneum containing intercellular lamellar lipid layers arranged in patterns analogous to those found in vivo.
TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1.5 °C
- Temperature of post-treatment incubation (if applicable): Room temperature
REMOVAL OF TEST MATERIAL AND CONTROLS
- Number of washing steps: 3 rinses with PBS
-Volume and number of washing steps:
* Tissue was removed from 6-well plate after exposure period and gently rinsed using a wash bottle containing PBS to remove any residual test material
* Excess PBS was removed by gently shaking the insert and blotting bottom with blotting paper.
* The insert was placed in a prepared holding plate. All inserts were treated in the same manner.
* Then the inserts were transferred into a prepared 24-well "MTT assay plate" containing 300 ul prewarmed MTT solution.
- Observable damage in the tissue due to washing: Not reported
- Modifications to validated SOP: Not reported
DYE BINDING METHOD
- Dye used in the dye-binding assay: MTT Formazan salt (Sigma Alrdrich) dissolved in PBS
- Spectrophotometer: Optical density was read in a microplate reader (Versamax Molecular Devices)
- Wavelength: 570 nm (OD570)
- Filter: without reference filter
NUMBER OF INDEPENDENT TESTING RUNS / EXPERIMENTS TO DERIVE FINAL PREDICTION:
PREDICTION MODEL / DECISION CRITERIA
- The test substance is considered to be corrosive to skin if 1) the viability after 3 minutes exposure is less than 50% or 2) the viability after 3 minutes exposure is greater than or equal to 50% and the vibility after 1 hour exposure is less than 15%
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater than or equal to 15%.
- The mean OD value obtained for hte duplicate tissues per tset item were used to calculate the percent viability relative to the negative control, which was arbitratily set at 100%.
- The absolute OD570 of the negative control tissues in the MTT-test is an indicator of tissue viability obtained in the testing laboratory after the shipping and storing procedure and under specific conditions of the assay. Tissue viability met the acceptance criterion if the mean OD570 of the two tissues in both treatment intervals was ≥0.8. The assay met the acceptance criterion if mean relative tissue viability of the positive control was ≤30%. - Control samples:
- yes, concurrent negative control
- yes, concurrent positive control
- Amount/concentration applied:
- TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 mg of the test material were applied to the tissues and wetted with 25 ul deionised water and spread to cover the surface of the tissue.
- Concentration (if solution): not specified
NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 ul per tissue
POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 ul per tissue - Duration of treatment / exposure:
- 1) 3 mins
2) 1 hour - Duration of post-treatment incubation (if applicable):
- 3 hour incubation period in MTT-plates at 37 ± 1.5 °C, 5 ± 0.5% CO2
- Number of replicates:
- Experiment performed in duplicate (2 replicates)
Results and discussion
In vitro
Resultsopen allclose all
- Irritation / corrosion parameter:
- % tissue viability
- Run / experiment:
- 3 minute exposure
- Value:
- ca. 1.015
- Vehicle controls validity:
- not examined
- Negative controls validity:
- valid
- Positive controls validity:
- valid
- Remarks on result:
- other:
- Remarks:
- No indication of corrosiveness
- Irritation / corrosion parameter:
- % tissue viability
- Run / experiment:
- 1 hour exposure
- Value:
- ca. 1.134
- Vehicle controls validity:
- not examined
- Negative controls validity:
- valid
- Positive controls validity:
- valid
- Remarks on result:
- other:
- Remarks:
- The test item is not corrosive to skin
- Other effects / acceptance of results:
- - OTHER EFFECTS:
- Visible damage on test system: not reported
- Direct-MTT reduction: No
- Colour interference with MTT: No
ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: After exposure to the negative control the absorbance values exceeded the required acceptability criterion of mean OD570 ≥ 0.8 for both treatment intervals thereby confirming the acceptable quality of the tissues.
- Acceptance criteria met for positive control: Exposure to the positive control decreased the relative absorbance as compared to the negative control to 27.3% for the 3 minutes exposure period and 0.5% for the 1 hour exposure period thus confirming the validity of the test system.
- Acceptance criteria met for variability between replicate measurements: Not reported
Any other information on results incl. tables
Results after treatment with test item L-Cystine and with the positive and the negative control
Dose Group | Exposure Interval | Absorbance 570 nm Tissue 1* | Absorbance 570 nm Tissue 2* | Mean Absorbance of 2 Tissues | Rel. Absorbance [% of Negative Control]** |
Negative Control | 3 min | 0.941 | 1.000 | 0.970 | 100.0 |
Positive Control | 3 min | 0.242 | 0.288 | 0.265 | 27.3 |
L-Cystine L-Cystine | 3 min | 0.997 | 1.033 | 1.015 | 104.6 |
Negative Control | 1 hour | 0.944 | 1.028 | 0.986 | 100.0 |
Positive Control | 1 hour | 0.004 | 0.005 | 0.004 | 0.5 |
L-Cystine | 1 hour | 1.201 | 1.067 | 1.134 | 115.0 |
* mean of three replicate wells after blank correction
** relative absorbance [rounded values]: 100 x (absorbancetest item) / (absorbancenegative control)
The optical evaluation of the MTT-reducing capacity of the test item after one hour incubation with MTT-reagent did not show evidence of a blue colour and thereby was not considered to be an MTT reducer.
The test item L-Cystine is not considered to be corrosive to skin:
1) since the viability after 3 minutes exposure is greater than 50% and
2) the viability after 1 hour exposure is greater than 15%.
Applicant's summary and conclusion
- Interpretation of results:
- GHS criteria not met
- Remarks:
- Test item L-Cystine is not considered to be corrosive to skin
- Conclusions:
- In an in vitro skin corrosion test (OECD 431) using the human skin model EST-1000™ the test item was tested as non-corrosive.
- Executive summary:
The potential of L-Cystine to induce skin corrosion was analysed by using the epidermis model EST-1000™, derived from human keratinocytes and consists of normal, humanderived epidermal keratinocytes (NHEK) which have been cultured to form a multilayered, highly differentiated model of the human epidermis. The NHEK, which are cultured on specially prepared cell culture inserts using serum free medium, attain levels of differentiation at the cutting edge of in vitro skin technology. Ultrastructurally, the skin models closely parallel human skin. The test item was applied topically to the EST-1000™ tissue for 3 minutes and 1 hour followed by immediate determination of cytotoxic effects via MTT reduction assay.
Corrosivity potential of the test item was predicted from the relative absorbance values compared to the corresponding negative control tissues concurrently treated with deionised water. The positive control (8.0 N KOH) did induce the appropriate response. The controls confirmed the validity of the study. In this study under the given conditions the test item showed no corrosive effects. After exposure to the test item L-Cystine, the relative absorbance values did not decrease, neither after the 3 minutes exposure (104.6%; threshold for corrosivity: 50%), nor after the 1 hour exposure (115.0%; threshold for corrosivity: 15%). Therefore, the test item was not considered to be corrosive.
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