3-Pentanone, 1-hydroxy-2-methyl-

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

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

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:

1-hydroxy-2-methylpentan-3-one

EC Number:

939-893-5

Cas Number:

27970-79-2

Molecular formula:

C6 H12 O2

IUPAC Name:

1-hydroxy-2-methylpentan-3-one

Test material form:

liquid

Specific details on test material used for the study:

Test-substance No.: 15/0439-1
Batch identification: J 1812
Purity: 90.6 area-%
Homogeneity: The test substance was homogeneous by visual inspection.
Storage stability: The stability under storage conditions over the study period was guaranteed by the sponsor.
pH-value: Ca. 5 (undiluted test substance; determined in the lab prior to start of the GLP study)
Physical state / color: Liquid / yellowish, clear
Storage conditions: Room temperature, protect against humidity ; no direct sunlight

In vitro test system

Test system:

human skin model

Source species:

human

Vehicle:

unchanged (no vehicle)

Details on test system:

The EpiDermTM model consists of normal, human-derived epidermal keratinocytes which have been cultured to form a multi layered, highly differentiated model of the human epidermis. It consists of organized basal, spinous and granular layers, and a multi-layered stratum corneum containing intercellular lamellar lipid layers arranged in patterns analogous to those found in vivo. The EpiDermTM tissues (surface 0.6 cm²) are cultured on specially prepared cell culture inserts (MILLICELLs, 10 mm diameter) and commercially available as kits (EpiDerm™ 200), containing 24 tissues on shipping agarose.

Tissue model: EPI-200
Tissue Lot Number: 23309
Origin: MatTek In Vitro Life Science Laboratories, Bratislava, Slovakia

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

Fifty microliter (50 μL) of the undiluted liquid test substance was applied using a pipette.
Control tissues were concurrently treated with 50 μL of de-ionized water (NC) or with 50 μL of 8 N potassium hydroxide (PC).

Duration of treatment / exposure:

3 minutes at room temperature (2 tissues) and 1 hour in the incubator (2 tissues)

Number of replicates:

Two tissues per exposure time (3 minutes at room temperature or 1 hour in the incubator, as a rule) and test group (test material, negative control and positive control; 12 tissues per test)
were used.

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 min exposure mean

Value:

88.4

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1 hour exposure mean

Value:

13.7

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: no
- Direct-MTT reduction: no
- Colour interference with MTT: no


ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes
- Acceptance criteria met for positive control: yes
- Acceptance criteria met for variability between replicate measurements: yes

Any other information on results incl. tables

See "attached background material"

Applicant's summary and conclusion

Conclusions:

The borderline result of the skin corrosion test (viability of 13.7% after an exposure period of 1 hour) do not clearly allow the evaluation of the skin corrosion potential. On basis of the results of this study the corrosive potential of the test substance cannot be excluded.

Executive summary:

The potential of Hydroxymethylpentanon to cause dermal corrosion/irritation was assessed by a single topical application of 50 μL of the undiluted test substance to a reconstructed three dimensional human epidermis model (EpiDerm™).

Two EpiDerm™ tissues were incubated with the test substance for 3 minutes and 1 hour, each. Tissue destruction was determined by measuring the metabolic activity of the tissue after exposure/post-incubation using a colorimetric test. The reduction of mitochondrial dehydrogenase activity, measured by reduced formazan production after incubation with a tetrazolium salt (MTT) was chosen as endpoint. The formazan production of the test-substance treated epidermal tissues is compared to that of negative control tissues. The quotient of the values indicates the relative tissue viability.

The test substance is not able to reduce MTT directly. The mean viability of the test-substance treated tissues determined after an exposure period of 3 minutes was 88.4%, and it was 13.7% after an exposure period of 1 hour.

Based on the observed results it has to be concluded, that the results of the test substance Hydroxymethylpentanon should be considered “inconclusive” in the EpiDerm™ in vitro skin irritation and corrosion test strategy under the test conditions chosen.