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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
The study was performed between 14 February 2012 and 20 February 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-compliant, guideline study, available as an unpublished report.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report date:
2013

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: OECD Guideline 439 (In Vitro Skin Irritation)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
Lithium myristate
EC Number:
243-743-8
EC Name:
Lithium myristate
Cas Number:
20336-96-3
Molecular formula:
C14H28O2.Li
IUPAC Name:
lithium myristate
impurity 1
Chemical structure
Reference substance name:
Lithium hydroxide
EC Number:
215-183-4
EC Name:
Lithium hydroxide
Cas Number:
1310-65-2
Molecular formula:
HLiO
IUPAC Name:
lithium hydroxide
Test material form:
solid
Details on test material:
- Batch number: A194-99
- Expiry date: 30 June 2013

Test animals

Species:
other: EPISKIN (TM) human epidermis model
Strain:
other: not applicable
Details on test animals or test system and environmental conditions:
Not applicable

Test system

Type of coverage:
other: topical
Preparation of test site:
other: not applicable
Vehicle:
unchanged (no vehicle)
Controls:
other: not applicable
Amount / concentration applied:
- Treatment group: Approximately 10 mg lithium myristate was applied topically, ensuring an even covering, to the epidermis surface which had previously been moistened with 5 µL sterile, distilled water.
- Negative control: 10 µL Dulbecco's Phosphate Buffered Saline (DPBS) with Ca++ and Mg++
- Positive control: 10 µL Sodium Dodecyl Sulphate (SDS) at 5% w/v aqueous solution spread over entire surface of the epidermis using a pipette tip and re-spread after 7 minutes.
Duration of treatment / exposure:
- Treatment period: 15 minutes
- Post-exposure incubation: At the end of the exposure period, tissues were rinsed and incubated for 42 hours, at 37°C and 5% CO2 in air, in wells containing 2 mL maintenance media.
Observation period:
No applicable
Number of animals:
Not applicable
Details on study design:
- Approximately 10 mg of lithium myristate was applied to the epidermis surface, which had been previously moistened with 5µL sterile, distilled water. At the end of the 15 minute exposure period, each tissue was removed and rinsed with DPBS with Ca++ and Mg++ . The tissues were then incubated for 42 hours at 37°C and 5% CO2 in air, in wells containing 2 mL maintenance media.
- After incubation, the viability (cytotoxicity) of the treated tissues were compared to the negative control tissues, by means of a colourimetric MTT reduction assay. If the mean tissue viability is ≤50%, the substance is considered to be irritant.

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
other: other: Optical density at 540 nm
Value:
0.948
Remarks on result:
other:
Remarks:
Basis: mean. Time point: After a 15 minute exposure. Remarks: Negative control item. (migrated information)
Irritation / corrosion parameter:
other: other: Optical density at 540 nm
Value:
0.052
Remarks on result:
other:
Remarks:
Basis: mean. Time point: After a 15 minute exposure. Remarks: Positive control item. (migrated information)
Irritation / corrosion parameter:
other: other: Optical density at 540 nm
Value:
0.96
Remarks on result:
other:
Remarks:
Basis: mean. Time point: After a 15 minute exposure. Remarks: Test item. (migrated information)
Irritation / corrosion parameter:
other: other: Relative viability (%)
Value:
100
Remarks on result:
other:
Remarks:
Basis: mean. Time point: After a 15 minute exposure. Remarks: Negative control item (set at 100%). (migrated information)
Irritation / corrosion parameter:
other: other: Relative viability (%)
Value:
5.5
Remarks on result:
other:
Remarks:
Basis: mean. Time point: After a 15 minute exposure. Remarks: Positive control item. (migrated information)
Irritation / corrosion parameter:
other: other: Relative viability (%)
Value:
101.3
Remarks on result:
other:
Remarks:
Basis: mean. Time point: After a 15 minute exposure. Remarks: Test item. (migrated information)
Other effects / acceptance of results:
- Viability: The relative mean viability of the treated tissues was 101.3% after a 15-minute exposure period, with standard deviation of 5.2%
- Optical density: The mean optical density of the treated tissues at 540 nm was 0.96
- Conclusion: Lithium myristate is considered to be non-irritant using the EPISKIN (TM) human epidermis model (viability >50%)
- Positive control: The relative mean tissue viability was 5.5% relative to the negative control and the standard deviation was 3.3%
- Negative control: The mean optical density was 0.948 and the standard deviation was 5.0%

Any other information on results incl. tables

- Direct MTT reduction: The MTT solution containing lithium myristate did not turn blue, indicating that lithium myristate did not directly reduce MTT

- The positive and negative control acceptance criteria were satisfied according to the protocol criteria. The standard deviation of the triplicate treated tissues was 5.2% and hence the test item acceptance criterion was also satisfied.

Applicant's summary and conclusion

Interpretation of results:
not irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Lithium myristate is considered to be non-irritant using the EPISKIN (TM) human epidermis model.
Executive summary:

Lithium myristate is considered to be non-irritant using the EPISKIN (TM) human epidermis model. The skin irritation potential of lithium myristate was evaluated using EPISKIN (TM) reconstructed human epidermis model after a treatment period of 15 minutes followed by a post-exposure period of 42 hours using a colourimetric MTT reduction assay following OECD guideline 439 in an experimental proprietary study (Harlan 2013). The quality criteria required for the acceptance of results in the test were satisfied and the study is considered relevant and reliable for use.