Phosphoric acid, C12-18-alkyl esters, potassium salts

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-12-06 to 2017-12-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Version / remarks:

adopted July 29, 2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Phosphoric acid, C12-18-alkyl esters, potassium salts

EC Number:

291-905-1

EC Name:

Phosphoric acid, C12-18-alkyl esters, potassium salts

Cas Number:

90506-43-7

Molecular formula:

Not applicable for UVCB substance

IUPAC Name:

Phosphoric acid, C12-18-alkyl esters, potassium salts

Test material form:

solid

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

recommended by the OECD testing guideline 431

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm™ tissues
- Tissue batch number(s): Lot: 25867
-Certificate of analysis dated: 2017-12-20
- Date of initiation of testing: 2017-12-22

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 3 min exposure at room temperature; 60 min exposure at 37 ± 1.5 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: 20 times with exess of DPBS
- Observable damage in the tissue due to washing: not reported

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 300 µL (1 mg/mL)
- Incubation time: 3 hours
- Spectrophotometer: Versamax®, Molecular Devices, SoftMax Pro Enterprise (version 4.7.1)) at 570 nm (OD570)
- Wavelength: at 570 nm (OD570)
- Filter: no
- Linear OD range of spectrophotometer: no information

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: valid
- Barrier function: valid
- Morphology: valid
- Contamination: valid
- Reproducibility: valid

NUMBER OF REPLICATE TISSUES: two tissues

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
Test item did not prove to be a MTT reducer

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: one test

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if [complete, e.g. the viability after 3 minutes exposure is less than 50%, or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.]
- The test substance is considered to be non-corrosive to skin if [complete, e.g. 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%.]
- Justification for the selection of the cut-off point(s) if different than recommended in TG 431 and 439:

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 ± 2mg /tissue

VEHICLE
No vihicle

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 µL deionised water

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50µL Potassium Hydroxide
- Concentration (if solution): 8.0 N

Duration of treatment / exposure:

Test Item: 3 ± 0.5 minutes, 60 ± 5 minutes
Negative Control: 3 ± 0.5 minutes, 60 ± 5 minutes
Positive Control: 3 ± 0.5 minutes, 60 ± 5 minutes

Duration of post-treatment incubation (if applicable):

no

Number of replicates:

Duplicate EpiDermTM tissues

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 minutes

Value:

71.3

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: no indication of corrosion

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1 houre

Value:

46.8

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: no indication of corrosion

Any other information on results incl. tables

Results after treatment with Phosphoric acid, C12-18 alkyl esters, potassium salts and the controls

 

Dose Group	Ex-posure Inter-val	OD570 Well 1 (Tissue 1/2)	OD570 Well 2 (Tissue 1/2)	OD570 Well 3 (Tissue 1/2)	Mean OD570(Tissue 1/2)	OD570of 3 Wells blank corrected	OD570of 2 Tissues	Rel. Viability of Tissue 1/2 [%]*	CV [%]	Mean Rel. Viability [%]**
Blank		0.039	0.038	0.038	0.039
Negative Control	3 minutes	1.576	1.503	1.526	1.535	1.496	1.535	97.5	3.6	100.0
		1.633	1.596	1.609	1.613	1.574		102.5
Positive Control		0.265	0.258	0.258	0.260	0.222	0.282	14.5	30.1	18.4
		0.384	0.377	0.380	0.380	0.342		22.3
Test Item		1.218	1.175	0.187	1.193	1.155	1.095	75.2	7.7	71.3
		1.066	1.056	1.101	1.074	1.036		67.5
Blank		0.039	0.038	0.038	0.039
Negative Control	1 hour	1.714	1.682	1.705	1.700	1.662	1.654	100.4	0.6	100.0
		1.676	1.692	1.689	1.686	1.647		99.6
Positive Control		0.082	0.080	0.081	0.081	0.042	0.039	2.6	11.7	2.4
		0.075	0.074	0.074	0.074	0.036		2.2
Test Item		0.815	0.797	0.819	0.810	0.772	0.773	46.7	0.3	46.8
		0.839	0.797	0.805	0.814	0.775		46.8

 

Conclusion

The test item is considered to be non-corrosive to skin:

·        since the viability after 3 minutes exposure is greater than 50% and

·        the viability after 1 hour exposure is greater than 15%.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

non-corrosive to skin

Conclusions:

Phosphoric acid, C12-18-alkyl esters, potassium salts is considered to be not corrosive, based on GHS criteria.

Executive summary:

In an in-vitro skin irritation study performed in accordance with OECD Guideline 431 (In Vitro Skin Corrosion, RHE) (adopted July 29, 2016), Phosphoric acid, C12-18-alkyl esters, potassium salts (99 % a.i.) was applied to the three-dimensional human epidermis model tissue for an exposure period of 3 minutes and 1 hour in duplicate.

Approximately 25 mg of the test item were applied to the surface of tissues, wetted with 25 µL of deionised water prior to application in order to improve contact between the solid and the tissue.

The test item was spread to match the surface of the tissue. Each 50 µL of negative and positive control were applied to sets of duplicate tissues, respectively.

After exposure period of 3 minutes (room temperature) and 1 hour (37 °C) the tissues were rinsed off, and a 3 hour incubation period (37 ± 1 °C, 5 ± 0.5 % CO2) with MTT solution followed. After rinsing, the formazan salt was extracted for about 20 hours at room temperature.

Cytotoxicity was expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT at the end of the treatment.

Exposure to the positive control induced a decrease in the relative absorbance as compared to the negative control, both for the 3 minutes exposure period (18.4%) and for the 1 hour exposure period (2.4%) thus confirming the validity of the test system and the specific batch of tissue models.

After exposure to the test item Phosphoric acid, C12-18 alkyl esters, potassium salts the relative absorbance value decreased to 71.3% after 3 minutes exposure. After 1 hour exposure the relative absorbance value was reduced to 46.8%. Both values did not exceed the threshold for corrosivity which is defined to be < 50% after the 3 minutes exposure and < 15% after the 1 hour exposure. Therefore, the test item is considered to be not corrosive.