6-chlorohexan-2-one

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From October 16th to October 17th, 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 430 (In Vitro Skin Corrosion: Transcutaneous Electrical Resistance Test Method (TER))

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.40 (In Vitro Skin Corrosion: Transcutaneous Electrical Resistance Test (TER))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

6-chlorohexan-2-one

EC Number:

233-546-5

EC Name:

6-chlorohexan-2-one

Cas Number:

10226-30-9

Molecular formula:

C6H11ClO

IUPAC Name:

6-chlorohexan-2-one

Test material form:

liquid

In vitro test system

Test system:

isolated skin discs

Source species:

rat

Cell type:

other: Dorso-lateral skin of rats

Cell source:

other: Dorso-lateral skin of rats

Source strain:

Wistar

Details on animal used as source of test system:

SOURCE ANIMAL
- Source: skin discs were collected from 2 female rats (outbred) obtained from the conventional husbandry of laboratory animals of the Centre for Experimental Medicine at the Medical University in Katowice.
- Sex: female
- Age at study initiation (in days): 30-day-old (when skin discs were obtained)
- Weight at study initiation: Not specified
- Housing: During the quarantine period, the animals were kept in air-conditioned rooms under the following conditions:
- air temperature: 20 - 23°C
- relative air humidity: 30 – 53%
- artificial fluorescent lighting; lighting cycle: 12 hours light/12 hours dark
- facility air exchange: about 13-16 times/hour
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Quarantine period: Animals were quarantined and observed daily for 3 days

Justification for test system used:

OECD Guideline 430 is based on the rat skin transcutaneous electrical resistance (TER) test method, which utilizes skin discs to identify corrosives by their ability to produce a loss of normal stratum corneum integrity and barrier function

Vehicle:

unchanged (no vehicle)

Details on test system:

SKIN DISC PREPARATION
- Procedure used:
After euthanasia, the dorso-lateral skin of each animal (2 rats) was removed and stripped of excess subcutaneous fat by carefully peeling it away from the skin using a paper towel. The skin discs were cut out using a scalpel. Each skin disc was placed over one of the ends of a PTFE (polytetrafluoroethylene) tube, ensuring that the epidermal surface was in contact with the tube. A rubber ‘O’ ring was press-fitted over the end of the tube to hold the skin in place and excess tissue is trimmed away. The tube was supported by a spring clip inside a receptor chamber containing MgSO4 solution (154 mM). The skin disc should be fully submerged in the MgSO4 solution. As many as 11 skin discs with a diameter of 20-mm each were obtained from a single rat skin. Two of them were used to control the quality of the procedure, whereas the remaining nine were used for the purpose of the experiment.
- Quality control for skin discs: Electrical resistance obtained with the two isolated skin discs mentioned before should be greater than 10 kΩ for the remainder of the discs to be used for the test.

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 21-22°C


REMOVAL OF TEST MATERIAL AND CONTROLS
- Number of washing steps: 1 (the test item and the control items were removed by washing with a jet of tap water at up to 30°C)

DYE BINDING METHOD
The dye binding procedure was not necessary in this case since all TER values for the test item were higher than 5 kΩ and there were not any visible changes on the skin discs.

NUMBER OF INDEPENDENT TESTING RUNS / EXPERIMENTS TO DERIVE FINAL PREDICTION: 2

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the mean TER value obtained for the test item is less than or equal to 5 kΩ and the skin disc is obviously damaged.
- The test substance is considered to be non-corrosive to skin if the mean TER value obtained for the test item is greater than 5 kΩ, or the mean TER value is less than or equal to 5 kΩ, and the skin disc shows no obvious damage.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 150 μL (undiluted test item)

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 150 μL

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 150 μL

Duration of treatment / exposure:

24 h

Duration of post-treatment incubation (if applicable):

Not applicable.

Number of replicates:

3

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

transcutaneous electrical resistance (in kΩ)

Run / experiment:

Animal 1 (mean)

Value:

ca. 17.8

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

transcutaneous electrical resistance (in kΩ)

Run / experiment:

Animal 2 (mean)

Value:

ca. 12.13

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: The gross examination showed that the skin discs treated with the test item did not reveal any changes.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes. The mean TER values for negative control (distilled water) were 18.72 kΩ (animal no. 1) and 18.11 kΩ (animal no. 2)
- Acceptance criteria met for positive control: yes. The mean TER values for positive control (10M HCl solution) were 0.91 kΩ (animal no. 1) and 0.93 kΩ (animal no. 2).

Any other information on results incl. tables

Table 1. Results of the control transcutaneous electrical resistance test (TER)

Animal number	Skin disc number	TER value (kΩ)
1	1	14.73
	2	11.52
2	1	13.28
	2	14.03

Table 2. Results of the transcutaneous electrical resistance test (TER)

Animal number	Tested substance	Skin disc number	TER value (kΩ)	Mean TER value ± SD (kΩ)
1	Positive control – 10M HCl	1	0.89	0.91 ± 0.02
		2	0.92
		3	0.91
	Negative control – distilled water	1	18.76	18.72 ± 0.67
		2	19.36
		3	18.03
	Test item	1	17.39	17.80 ± 0.36
		2	18.08
		3	17.92
2	Positive control – 10M HCl	1	0.93	0.93 ± 0.01
		2	0.92
		3	0.93
	Negative control – distilled water	1	17.91	18.11 ± 0.24
		2	18.38
		3	18.03
	Test item	1	11.76	12.13 ± 0.51
		2	11.92
		3	12.71

 

Table 3. Gross changes on the surface of the treated skin discs

Animal number	Tested substance	Skin disc number	Gross changes
1	Positive control – 10M HCl	1	perforation
		2	perforation
		3	perforation
	Negative control – distilled water	1	No changes
		2	No changes
		3	No changes
	Test item	1	No changes
		2	No changes
		3	No changes
2	Positive control – 10M HCl	1	perforation
		2	perforation
		3	perforation
	Negative control – distilled water	1	No changes
		2	No changes
		3	No changes
	Test item	1	No changes
		2	No changes
		3	No changes

Applicant's summary and conclusion

Interpretation of results:

other: Non corrosive (according to CLP regulation)

Conclusions:

Based on the study results, the test item was considered as non-corrosive to skin.

Executive summary:

An in vitro skin corrosion: transcutaneous electrical resistance test (TER) was performed on the test substance in accordance with the OECD nº430 with GLP. Skin discs used in the experiment were obtained from two 30-day-old Wistar female rats. Before the start of the experiment, TER of two skin discs obtained from each animal was measured to check that the values were greater than 10 kΩ, therefore, the rest of skin discs could be used in the experiment. The undiluted test item and concurrent positive (10M hydrochloric acid) and negative (distilled water) controls were applied uniformly to the skin discs in a volume of 150 μL for 24 h. Then, they were removed by washing with a jet of tap water. For the test item and the control items, three skin discs were used (three replicates). The mean TER results for the skin discs treated with the test item were equal to 17.80 kΩ (animal no. 1) and 12.13 kΩ (animal no. 2). The concurrent positive and negative control values fell within the acceptable ranges. Gross examinations of the skin discs treated with the test item did not reveal any pathological changes. Based on these results, the test item was considered to be non-corrosive to skin, as mean TER values were higher than 5 kΩ and there were not any visible changes on the skin discs.