Urea, reaction products with formaldehyde and glyoxal

Endpoint summary

Description of key information

Skin irritation/corrosion in vitro: not irritating
Skin irritation in vivo (rabbit): not irritating
Eye irritation in vivo (rabbit): not irritating

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

other: OECD: Draft Proposal for a New Guideline on In Vitro Skin Irritation: human Skin Model Test of 06-Jun-2008

GLP compliance:

yes (incl. QA statement)

Species:

other: EpiDerm TM Skin Corrosivity Test

Strain:

other: not applicable

Type of coverage:

other: not applicable

Preparation of test site:

other: not applicable

Vehicle:

unchanged (no vehicle)

Controls:

yes

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 20 mg of the test substance

Duration of treatment / exposure:

1 hour

Observation period:

not applicable

Number of animals:

not applicable

Details on study design:

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 ∅) and commercially available as kits (EpiDerm™ 200), containing 24 tissues on shipping agarose.

TEST PROCEDURE
Three EpiDerm™ tissue samples were incubated with the test substance for 1 hour followed by a 42-hours post-incubation period.
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 suitable endpoint. The formazan production of the testsubstance treated epidermal tissues is compared to that of negative control tissues. The quotient of both values indicates the relative tissue viability.

CONTROLS
-Negative control (NC): PBS, sterile
-Positive control (PC): 5 % sodium dodecyl sulfate (SDS, Sigma,Germany in highly de-ionized water, sterile

ASSAY ACCEPTANCE CRITERIA:
-Negative control (NC): mean OD570 of the NC is ≥ 1.0.
-Positive Control (PC): 5% SDS is used as PC and reflects the sensitivity of the tissues used in the test conditions. A viability of ≤ 20% is acceptable.

-Tissue variability: For every treatment, 3 tissues are treated in parallel. The inter-tissue variability is considered to be acceptable if the SD of %-viability is ≤ 20.

Test article		Tissue 1	Tissue 2	Tissue 3	Mean	SD
NC	Mean OD570	1.8343	1.5913	1.8213	1.7490
	Viabillity [% of NC]	104.9	91.0	104.1	100	7.82
09/0299-1	Mean OD570	1.8938	1.6333	1.8823	1.8032
	Viabillity [% of NC]	108.3	93.4	107.6	103	8.42
PC	Mean OD570	0.1428	0.1698	0.1383	0.1503
	Viabillity [% of NC]	8.2	9.7	7.9	9	0.97

 

The EpiDerm skin irritation test showed the following results:

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 1 hour with about 42 hours post-incubation was 103%.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Centre Lago S.A., Vonnas, France
- Age at study initiation: 6 -7 months
- Weight at study initiation: 3.92-4.01 kg
- Housing: single housing
- Diet (e.g. ad libitum): Kliba Labordiät (Kaninchen & Meerschweichenhaltung "GLP")
- Water (e.g. ad libitum): ad. libitum
- Acclimation period: 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 -24
- Humidity (%): 30 - 70
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

unchanged (no vehicle)

Controls:

other: Untreated felt eye

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 ml

Duration of treatment / exposure:

24 hours

Observation period (in vivo):

72 hours

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: 24 hours

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

other: 24h - 48h - 72h

Score:

0

Max. score:

0

Reversibility:

fully reversible within: 72 hours

Irritation parameter:

iris score

Basis:

mean

Time point:

other: 24h - 48h - 72h

Score:

0

Max. score:

0

Reversibility:

fully reversible within: 72 hours

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

other: 24h - 48h - 72h

Score:

0.7

Max. score:

4

Reversibility:

fully reversible within: 72 hours

Irritation parameter:

chemosis score

Basis:

mean

Time point:

other: 24h - 48h - 72h

Score:

0.2

Max. score:

4

Reversibility:

fully reversible within: 72 hours

Other effects:

In addition, injected scleral vessels in a circumscribed area or circular were noted in the animals during the observation period.

Readings	Animal	Cornea		Iris	Conjunctiva			Additional findings
		Opacity	Area of cornea involved		Redness	Chemosid	Discharge
1h	01	0	0	0	2	2	3	49
	02	0	0	0	2	2	1	49
	03	0	0	0	2	2	3	49
24 h	01	0	0	0	1	0	1	48
	02	0	0	0	2	1	0	48
	03	0	0	0	1	1	1	48
48 h	01	0	0	0	0	0	0
	02	0	0	0	1	0	0	48
	03	0	0	0	1	0	0	48
72 h	01	0	0	0	0	0	0
	02	0	0	0	0	0	0
	03	0	0	0	0	0	0
Mean 24-72 h	01	0.0		0.0	0.3	0.0
	02	0.0		0.0	1.0	0.3
	03	0.0		0.0	0.7	0.3
Mean		0.0		0.0	0.7	0.2

48 = scleral vessels injected, circumscribed area

49 =scleral vessels injected, circular

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation/corrosion: 

In an in vitro skin irritation test according to OECD draft guideline in compliance with GLP (EpiDerm Test) the test substance did not show a skin irritation potential (BASF SE, 2010). According to the results from an in vivo skin irritation test in rabbits with a product containing 45 % test substance in water the test substance is considered to be not irritating to the skin (BASF AG, 1973).

 

Eye irritation: 

The test substance did not show an eye irritation potential in an acute eye irritation study in rabbits according to OECD TG 405 in compliance with GLP (BASF SE, 2010). This is supported by the results of an eye irritation study in rabbits with a product containing 45 % test substance in water where no eye irritation was observed (BASF AG, 1973).

 

Respiratory irritation: 

There are no data available concerning respiratory irritation of the test substance.

Justification for classification or non-classification

GHS classification according to Annex I 1272/2008 CLP (EU GHS):

no classification warranted