Reaction mass of 1-hydroxypentan-2-yl formate and 2-hydroxypentyl formate and pentane-1,2-diol and pentane-1,2-diyl diformate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 Feb - 21 Mar 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

adopted 28 Jul 2015

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Hess. Ministerium für Umwelt, Klimaschutz, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 1-hydroxypentan-2-yl formate and 2-hydroxypentyl formate and pentane-1,2-diol and pentane-1,2-diyl diformate

EC Number:

942-424-7

Molecular formula:

not applicable (reaction mass)

IUPAC Name:

Reaction mass of 1-hydroxypentan-2-yl formate and 2-hydroxypentyl formate and pentane-1,2-diol and pentane-1,2-diyl diformate

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: EpiDerm™ (EPI-200)

Source strain:

not specified

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE)
- Model used: EpiDerm™ (EPI-200) (MatTek Corporation, Bratislava, Slovakia)
- Tissue batch number: 23324
- Delivery date: 15 March 2016
- Date of initiation of testing: 15 March 2016

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1.5 °C for 35 min in the incubator; thereafter at room temperature for 25 min in a sterile bench

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: Tissues were gently rinsed with DPBS at least 15 times in order to remove any residual test material. After rinsing the inserts were submerged in DPBS at least 3 times. Afterwards the inserts were once again rinsed with DPBS from the inside and the outside.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL
- Incubation time: 3 h
- Spectrophotometer: microplate reader (Versamax, Molecular Devices, Softmax Pro v.4.7.1)
- Wavelength: 570 nm

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: The quality of the EpiDerm™ tissue was assessed by an MTT cell viability test.
- Barrier function: The barrier function was assessed by determination of the exposure time required to reduce tissue viability by 50% (ET-50) upon application of 100 µL of 1% Triton X-100. The ET-50 value was determined to be 5.59 h.
- Contamination: The cells used to produce the EpiDerm™ tissue were screened for the presence of viruses, bacteria, yeast and other fungi.

NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
Since the test substance did not directly reduce the MTT solution, an additional test with freeze-killed tissues was not performed.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount applied: 30 µL

NEGATIVE CONTROL
- Amount applied: 30 µL

POSITIVE CONTROL
- Amount applied: 30 µL
- Concentration: 5% aqueous solultion

Duration of treatment / exposure:

60 min

Duration of post-treatment incubation (if applicable):

41.5 h

Number of replicates:

triplicates for each treatment and control group

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Remarks:

mean value of 3 tissues

Run / experiment:

60 minutes exposure

Value:

56.9

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

OTHER EFFECTS:
- Direct-MTT reduction: The test substance did not interfere with the MTT assay (no reducing capacity).

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The negative control OD (1.635, 1.976 and 1.715) was in the range of ≥ 0.8 and ≤ 2.8 for every exposure time.
- Acceptance criteria met for positive control: Exposure to the positive control induced a decrease in the relative absorbance as compared to the negative control to 6.2% thus confirming the validity of the test system.
- Acceptance criteria met for variability between replicate measurements: The standard deviations of the 3 identical replicates of the test substance, positive and negative control in the main test were < 14%, thus meeting the acceptance criteria of the study.

Any other information on results incl. tables

Table 2. Results after treatment with the test substance and controls

Test group	Mean absorbance at 570 nm*			Rel. absorbance (%)**			SD (%)	Rel. absorbance (% of negative control)***
	Tissue 1	Tissue 2	Tissue 3	Tissue 1	Tissue 2	Tissue 3
Negative control	1.635	1.976	1.715	92.1	111.3	96.6	10.0	100.0
Positive control	0.124	0.095	0.111	7.0	5.3	6.3	13.2	6.2
Test substance	1.084	0.926	1.021	61.0	52.2	57.5	7.8	56.9

* Mean of three replicate wells after blank correction (blank = 0.037)

** Relative absorbance per tissue (rounded values): 100 × (absorbance tissue) / (absorbance negative control)

*** Relative absorbance per treatment group (rounded values): 100 × (absorbance test substance/positive control) / (absorbance negative control)

Applicant's summary and conclusion

Interpretation of results:

other: CLP/EU GHS criteria not met, no classification required according to Regulation (EC) No 1272/2008

Conclusions:

Under the conditions of the reconstructed human epidermis test the test substance does not possess any skin irritating potential.

Executive summary:

After treatment with the test item the mean relative absorbance value decreased to 56.9% compared to the relative absorbance value of the negative control. This value is above the threshold for irritancy of ≤ 50%. Therefore, the test item is not considered to possess an irritant potential.