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EC number: 856-079-4 | CAS number: 55860-35-0
- 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 sensitisation
Administrative data
- Endpoint:
- skin sensitisation: in chemico
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- Experimental start: 06 December 2019, Experimental end: 18 December 2019
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 020
- Report date:
- 2020
Materials and methods
Test guideline
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 442C (In Chemico Skin Sensitisation Assays addressing the Adverse Outcome Pathway key event on covalent binding to proteins)
- Version / remarks:
- 2019
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Type of study:
- direct peptide reactivity assay (DPRA)
Test material
- Reference substance name:
- 4-acetyl-2-methylbenzoic acid
- EC Number:
- 856-079-4
- Cas Number:
- 55860-35-0
- Molecular formula:
- C10H10O3
- IUPAC Name:
- 4-acetyl-2-methylbenzoic acid
- Test material form:
- solid: particulate/powder
Constituent 1
In chemico test system
- Details of test system:
- cysteine peptide, (Ac-RFAACAA-COOH)
- lysine peptide (Ac-RFAAKAACOOH)
- Details on the study design:
- Solutions for cysteine reactivity assay
Stock solution - A stock solution of 0.667 mM SPCC (0.501 mg SPCC/mL) was prepared by dissolving 20.1 mg of SPCC in 40.12 mL phosphate buffer pH 7.5. The mixture was stirred for 5 minutes followed by 5 minutes sonication.
SPCC reference control solutions - Three 0.5 mM SPCC reference control (RC) solutions (RCcysA, RCcysB and RCcysC) were prepared in amber vials by mixing 750 μL of the 0.667 mM SPCC stock solution with 250 μL ACN. In addition, a RCcysCMeOH sample was included to evaluate the effect of the solvent that was used to dissolve the test item on the Percent Peptide Depletion. The RCcysCMeOH sample was prepared by mixing 750 μL of the 0.667 mM SPCC stock solution with 200 μL ACN and 50 μL MeOH. A SPCC calibration curve was prepared.
Co-elution control, substance and positive control samples - co-elution control (CC) samples, test item samples and the cinnamic aldehyde positive control samples (PC) were prepared.
Solutions for lysine reactivity assay
Stock solution - A stock solution of 0.667 mM SPCL (0.518 mg SPCL/mL) was prepared by dissolving 20.6 mg of SPCL in 39.77 mL of ammonium acetate buffer pH 10.2 followed by stirring for 5 minutes.
SPCL reference control solutions - Three 0.5 mM SPCL reference control (RC) solutions (RClysA, RClysB and RClysC) were prepared in amber vials by mixing 750 μL of the 0.667 mM SPCL stock solution with 250 μL ACN. In addition, a RClysCMeOH sample was included to evaluate the effect of the solvent that was used to dissolve the test item on the Percent Peptide Depletion. The RClysCMeOH sample was prepared by mixing 750 μL of the 0.667 mM SPCL stock solution with 250 μL MeOH. A SPCL peptide calibration curve was prepared.
Co-elution control, substance and positive control samples - co-elution control (CC) samples, test item samples and the cinnamic aldehyde positive control samples (PC) were prepared.
Sample incubation - After preparation, the samples (reference controls, calibration solutions, co-elution control, positive controls and test item samples) were placed in the autosampler in the dark and incubated at 25±2.5°C. The incubation times between placement of the samples in the autosampler and analysis of the first RCcysB- or RClysB-sample was 22.9 hours. The time between the first RCcysB- or RClysB-injection and the last injection of a cysteine or lysine sequence did not exceed 30 hours. Prior to HPLC analysis the samples were visually inspected for precipitation. The samples that showed precipitation were centrifuged (at 400 g) for 5 minutes at room temperature and supernatant was transferred to a new vial.
HPLC analysis - SPCC and SPCL peak areas in the samples were measured by HPLC. Sample analysis was performed using the following systems:
System 1 (used for Cysteine Reactivity Assay):
• Alliance separations module 2695 (Waters, Milford, MA, USA)
• Dual λ absorbance detector 2487 (Waters)
System 2 (used for Lysine Reactivity Assay):
• Alliance separations module 2695 (Waters, Milford, MA, USA)
• Dual λ absorbance detector 2487 (Waters) - Vehicle / solvent:
- other: Methanol
- Positive control:
- cinnamic aldehyde
Results and discussion
- Positive control results:
- The mean Percent SPCC Depletion for the positive control cinnamic aldehyde was 71.7% ± 0.3%. This was within the acceptance range of 60.8% to 100% with a SD that was below the maximum (SD <14.9%). The Percent SPCL Depletion was calculated versus the mean SPCL peak area of Reference Controls C. The mean Percent SPCL Depletion for the positive control cinnamic aldehyde was 65.2% ± 3.5%. This was within the acceptance range of 40.2% to 69.0% with a SD that was below the maximum (SD <11.6%).
In vitro / in chemico
Resultsopen allclose all
- Key result
- Group:
- test chemical
- Run / experiment:
- run/experiment 3
- Parameter:
- lysine depletion
- Value:
- 3.3 %
- At concentration:
- 0.469 mM
- Vehicle controls validity:
- valid
- Negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Key result
- Group:
- test chemical
- Run / experiment:
- run/experiment 2
- Parameter:
- lysine depletion
- Value:
- 0.8 %
- At concentration:
- 0.481 mM
- Vehicle controls validity:
- valid
- Negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Key result
- Group:
- test chemical
- Run / experiment:
- run/experiment 1
- Parameter:
- lysine depletion
- Value:
- 0 %
- At concentration:
- 0.485 mM
- Vehicle controls validity:
- valid
- Negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Key result
- Group:
- test chemical
- Run / experiment:
- run/experiment 3
- Parameter:
- cysteine depletion
- Value:
- 0.6 %
- At concentration:
- 0.502 mM
- Vehicle controls validity:
- valid
- Negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Key result
- Group:
- test chemical
- Run / experiment:
- run/experiment 2
- Parameter:
- cysteine depletion
- Value:
- 0.2 %
- At concentration:
- 0.504 mM
- Vehicle controls validity:
- valid
- Negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Key result
- Group:
- test chemical
- Run / experiment:
- run/experiment 1
- Parameter:
- cysteine depletion
- Value:
- 0 %
- At concentration:
- 0.505 mM
- Vehicle controls validity:
- valid
- Negative controls validity:
- not applicable
- Positive controls validity:
- valid
- Outcome of the prediction model:
- no or minimal reactivity [in chemico]
- Other effects / acceptance of results:
- All acceptability criteria for the cysteine and lysine reactivity assays were met confirming the suitability of the HPLC system and the stability of the HPLC runs over time.
Applicant's summary and conclusion
- Interpretation of results:
- other: Negative result is considered in a weight-of-evidence approach
- Conclusions:
- The substance was negative in the DPRA and was classified in the “moderate reactivity class” when using the Cysteine 1:10 / Lysine 1:50 prediction model.
- Executive summary:
The reactivity of the substance towards model synthetic peptides containing either cysteine (SPCC) or lysine (SPCL) was studied under GLP to OECD TG 442c. After incubation of the test item with either SPCC or SPCL, the relative peptide concentration was determined by High-Performance Liquid Chromatography (HPLC) with gradient elution and spectrophotometric detection at 220 nm and 258 nm. SPCC and SPCL Percent Depletion Values were calculated and used in a prediction model which assigns the test item to one of four reactivity classes used to support the discrimination between sensitizers and nonsensitizers. Methanol was found to be an appropriate solvent to dissolve the test item and was therefore used in this Direct Peptide Reactivity Assay (DPRA) study. The validation parameters, i.e., calibration curve, mean concentration of Reference Control (RC) samples A, C and CACN:MQ, the CV for RC samples B and C, the mean percent peptide depletion values for the positive control with its standard deviation value and the standard deviation value of the peptide depletion for the test item, were all within the acceptability criteria for the DPRA. In the cysteine reactivity assay the test item showed 0.3% SPCC depletion while in the lysine reactivity assay the test item showed 1.4% SPCL depletion. The mean of the SPCC and SPCL depletion was 0.8% and as a result the test item was considered to be negative in the DPRA and classified in the “No or minimal reactivity class” when using the Cysteine 1:10 / Lysine 1:50 prediction model.
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