Urea, reaction products with diethylene glycol, formaldehyde and glyoxal

Endpoint summary

Description of key information

Bovine Corneal Opacity and Permeability Test (OECD 437, BASF SE, 2011): no serious eye damage
EpiOcular™ Eye Irritation Test (GLP, BASF SE, 2011): not eye irritating
EpiDerm™ Skin Irritation Test (OECD 439, BASF SE, 2011): not skin irritating

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Eye irritation:

The potential of Fixapret PC, vor Magnesiumchlorid-Zugabe to cause serious damage to the eyes was assessed using the Bovine Corneal Opacity and Permeability Test according to the OECD guideline 437 and GLP. A single topical application of 750 μL of the undiluted test substance was given to the epithelial surface of isolated bovine corneas. Three corneas were treated with the test substance. Control corneas were incubated with 750 μL of highly deionized water (negative control, NC, 3 corneas) or with 750 μL of 1% (w/v) solution of sodium hydroxide in highly de-ionized water (positive control, PC, 2 corneas). After 10 minutes the test substance, NC and PC were removed and the epithelium was washed 4 times with medium and was then covered with fresh medium. Corneal opacity was measured quantitatively after a post-incubation period of 2 hours as the amount of light transmission through the cornea. Permeability was measured quantitatively as the amount of sodium fluorescein dye that passes across the full thickness of the cornea. Both measurements were used to calculate an In Vitro Irritancy Score (IVIS) of the test substance relative to the control corneas. The IVIS of the test substance was calculated to be -4.6 while an IVIS < 55 indicates that the test substance does not cause serious eye damage. Result: no serious eye damage.

The potential of Fixapret PC, vor Magnesiumchlorid-Zugabe to cause ocular irritation was assessed using the EpiOcular™ test protocol which meets generally accepted scientific standards, is described in sufficient detail and was performed according to GLP. The test is based on the treatment of a reconstructed three dimensional human cornea model. Two EpiOcular™ tissue samples were incubated with 50µl of the undiluted test substance. Control tissues were concurrently applied with 50 μL of highly de-ionized water (negative control, NC) or with 50 μL of methyl acetate (positive control, PC). After 30 minutes the tissues were washed three times with PBS and covered with fresh medium for 12 minutes. Then the medium was changed again followed by a 2-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 endpoint. Therefore the tissues were incubated with MTT solution for 3 hours, washed with PBS and the formazan that was metabolically produced by the tissues was extracted by incubation of the tissues in isopropanol at room temperature overnight or for at least 2 hours. The optical density at a wavelength of 570 nm (OD570) of the extracts was determined spectrophotometrically.The formazan production of the testsubstance treated epidermal tissues is compared to that of negative control tissues. The quotient of the values indicates the relative tissue viability which was calculated to be 90% for the test substance while a viability > 60% indicates that the test substance is non-irritant. Result: Test substance is not irritating to the eye.

Skin irritation/corrosion:

The potential of Fixapret PC, vor Magnesiumchlorid-Zugabe to cause dermal irritation was assessed using the EpiDerm™ Skin Irritation Test according to the OECD guideline 439 and GLP. The test is based on the treatment of a reconstructed three dimensional human epidermis model.

Three EpiDerm™ tissue samples were incubated with thirty microliter (30 μL) of the undiluted test substance, 30 μL of sterile PBS (negative control, NC) and with 30 μL of 5% SDS (positive control, PC), respectively. After 1 hour the tissues were washed with sterile PBS to remove residual test material and covered with fresh medium. After 24 ± 2 hours the tissues were transferred into new 6-well plates pre-filled with 0.9 mL of fresh medium and placed into the incubator for additional 18 ± 2 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 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 which was calculated to be 98% for the test compound while a viability > 50% indicates that the test substance does not cause skin irritation. Result: The test substance is not irritating to the skin.

Justification for classification or non-classification

Based on the available data, the test substance is not classified with regard to eye irritation according to Directive 67/548/EEC (DSD) and Regulation (EC) No 1272/2008 (CLP), respectively.