2(1H)-Pyridinone, 4-amino-5-methyl-

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 2018

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: Human Skin Model Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4-amino-5-methyl-1,2-dihydropyridin-2-one

EC Number:

682-818-3

Cas Number:

95306-64-2

Molecular formula:

C6 H8 N2 O

IUPAC Name:

4-amino-5-methyl-1,2-dihydropyridin-2-one

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:

commercially available test method

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: epiCS® (CellSystems, Troisdorf, Germany).
- Cat.-No: CS-1001

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: RT (room temperature)
- Temperature of post-treatment incubation (if applicable): Incubator temperature: 37 ± 2° C (CO2 gas concentration: 5 %; Humidity: maximum)

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1mg/ml
- Incubation time: 3 hours
- Spectrophotometer: EL808, Bio-Tek
- Wavelength: 570 nm

PREDICTION MODEL / DECISION CRITERIA:
- Corrosivity potential of test materials is predicted from the cell viabilities obtained after 3 min and 60 min treatment compared to the negative control. A chemical is classified "corrosive" (sub-category 1A) if the cell viability after 3 min treatment is decreased by more than 50 %. If cell viability after 3 min exposure is ≥ 50 %, while it is below 15 % after 60 min exposure the substance is also classified as corrosive, but sub-category 1 B/1 C. If cell viability after 3 min exposure is ≥ 50 % and after 60 min exposure ≥ 15 %, the substance is classified as non-corrosive.

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
Reliability of the test was previously confirmed by interlaboratory validation

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 mg (plus 50 µl 0.9% NaCl to moisten and ensure good contact with the epidermis surface)

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 µl
- Concentration (if solution): 0.9% NaCl

Duration of treatment / exposure:

3 and 60 minutes

Number of replicates:

3

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

cell viability after 3 min [%]

Value:

ca. 110

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

cell viability after 60 min [%]

Value:

ca. 93

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: No
- Direct-MTT reduction: No - according to the results of the pre-check
- Colour interference with MTT: No - according to the results of the pre-check

DEMONSTRATION OF TECHNICAL PROFICIENCY:
- Reliability of the test was previously confirmed by interlaboratory validation

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

Table 1: Tabular summary of the results   

Sample No.	Test item	Time (min)	OD mean *	Std Dev	% Viability
1 - 3	Negative control NaCl 0.9 %	60	2.05	0.07	100.00
4 - 6	Positive control 8N KOH	60	0.01	0.00	0.38
13 - 15	4 -Amino-5-methylpyridon	60	1.90	0.04	93.02
16 - 18	Negative control NaCl 0.9 %	3	1.71	0.02	100.00
25 - 27	4 -Amino-5-methylpyridon	3	1.88	0.12	109.87

* 6 values

Applicant's summary and conclusion

Interpretation of results:

other: negative

Executive summary:

A study for predicting a non-specific, corrosive potential of the test item by using reconstructed human epidermis (test method epiCS®) was performed according to OECD TG 431. For the determination of time related cytotoxic effects the incubation periods were 3 min. and 60 min. The MTT (Methylthiazoletetrazolium) viability test results (3 min.: 109.87 % viability; 60 min.: 93.02 % viability) showed, that the test item has no corrosive property under the conditions of the assay used.