Fatty acids, C16-18, lithium salts

Skin irritation / corrosion

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other: GLP-compliant, guideline study, available as an unpublished report.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

Test material information

Constituent 1

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

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

Results

Results 1

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)

Results 2

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)

Results 3

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)

Results 4

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)

Results 5

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)

Results 6

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.