1,3-dimethyl-1,3-diphenylurea

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

26.07.-29.07.2016

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

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

One tissue was rejected from evaluation due to having much higher OD570 than the other two. As absorbances of these two tissues were close together and not close to cut-off value, this deviation had no impact on the outcome of the study.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1,3-dimethyl-1,3-diphenylurea

EC Number:

210-283-4

EC Name:

1,3-dimethyl-1,3-diphenylurea

Cas Number:

611-92-7

Molecular formula:

C15H16N2O

IUPAC Name:

1,3-dimethyl-1,3-diphenylurea

Test material form:

solid: particulate/powder

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

other: normal human-derived epidermal keratinocytes

Cell source:

skin obtained from plastic surgery from multiple donors

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: model EpiDermTM
- Tissue: The reconstructed human epidermal model EpiDerm™ (EPI-200 ver. 2.0, MatTek, Bratislava, Slovakia); Lot No. 23347 kitL)
- Date of initiation of testing: 26.7.2016

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37±1°C

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied: 25 g

NEGATIVE CONTROL
PBS (phosphate buffered saline) prepared 25/02/2016, exp. 25/08/2016 and prepared 23/03/2016 exp. 23/09/2016
- Amount(s) applied: 25 µL


POSITIVE CONTROL
5 % SDS (sodium dodecyl sulphate), MatTek, Lot No. 012616TMB, exp. 26/01/2017

Duration of treatment / exposure:

60 min.

Duration of post-treatment incubation (if applicable):

42 hours

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Value:

100

Negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

Table No. 1: OD₅₇₀values obtained at the MTT test, their averages, standard deviations (%) and relative viabilities

	Treatment	OD570			Avg	SD	Average viability
		1	2	3			(% NC)
NC	PBS	1.926	1.806	1.646	1.793	0.115	100.0
	viability (%)	107.4	100.7	91.8	100.0	6.4
C4	322/16	1.763	1.822	2.942	1.793	0.030	100.0
	viability (%)	98.3	101.6	164.1	100.0	1.6
PC	5% SDS	0.052	0.052	0.046	0.050	0.003	2.8
	viability (%)	2.9	2.9	2.6	2.8	0.16

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the above-described experimental design, average viability of tissues treated by the test substance Methylcentralit was 100.0 % of negative control average value. No correction was done.
The test item is considered to have no category:
(ii) if the tissue viability after exposure and post-treatment incubation is more than (>) 50 %.
Even if the value obtained lay close cut-off value for the test, the effect of the test item was negative in EpiDermTM model.
According to the classification criteria given in chapter 4.5. of this report, the test item, Methylcentralit, is considered to have no category in accordance with UN GHS 1.

Executive summary:

The test item, Methylcentralit, was assayed for the in vitro skin irritation
in human epidermal model EpiDerm^TM.The test was performed according tothe OECD Test Guideline No.439:In VitroSkin Irritation: Reconstructed Human Epidermis Test Method (2015) and Protocol for: In Vitro EpiDerm^TMSkin Irritation Test For use with MatTek Corporation’s Reconstructed Human Epidermal Model EPI-200-SIT (see par. 1.4).

After pre-incubation of tissues, 25 mg of the test substance was placed directly a top to the previously moistened tissue and it was spread on the entire tissue surface. Length of exposition was 60 minutes. Three tissues were used for the test substance and every control.

After removal of the test substance, tissues were post-incubated for approximately 42 hours due to leave of damage reparation. Three hours incubation with MTT and two hours extraction period with shaking followed then. Optical density (OD₅₇₀) of isopropyl alcohol extracts was measured on a spectrophotometer. Relative cell viability was calculated for each tissue as % of the mean viability of the negative control tissues.

Isopropyl alcohol extract of one of three tissues was much higher than those of the other two. The outlying tissue was rejected from evaluation.

Average viability of the two evaluated treated tissues was 100.0% i.e. viability was >50 %.

The effect of the test item was negative in EpiDerm^TMmodel (tissues were not damaged).

According to the classification criteria given in chapter 4.5.,the test item, Methylcentralit, is considered to have no categoryin regard to skin irritation.