Rosin, reaction products with acrylic acid

Endpoint summary

Description of key information

In vitro eye irritation and skin irritation studies were conducted on MTDID 28640. The results of the studies were:

 

Eye Irritation: Not irritating when tested according to OECD 437.

Skin Irritation: Not corrosive when tested according to OECD 431.

Additional information

Eye Irritation:

 

The ocular irritation and corrosion potential of the test article was tested in the Bovine Corneal Opacity Permeability (BCOP) test. The test method was based on OECD 437 and was performed in compliance with GLP. The eyes were examined prior to use on the day of dosing. Any eye with a cornea exhibiting evidence of vascularization, pigmentation, opacity or scratches was discarded. Corneas from eyes that were free of defects were dissected from the surrounding tissues. A 2-3 mm rim of sclera was left attached to each cornea. The corneas were then placed in a container of fresh HBSS. The dissected corneas were mounted in holders and placed in chambers filled with MEM solution. The entire holder was incubated at 32°C for at least 1 hour but not longer than 2 hours. Corneas (3/group) were treated with 0.75 mL of the 20% (w/v) test article formulation in 0.9% saline and incubated in the horizontal position for 4 hours at 32°C. A positive control (20% w/v imidazole formulation in 0.9% saline), negative control (MEM solution), and a vehicle control (0.9% saline) were tested in parallel with the test material. At the end of the exposure period, the corneas were rinsed with a MEM solution containing phenol red; a final rinse was made with MEM without phenol red. Opacity was evaluated using the OP-KIT following the 4-hour exposure. Following opacity readings, the cell culture medium was replaced with 1.0 ml of 0.5% sodium fluorescein solution in Dulbecco's phosphate buffered saline (PBS) and incubated for approximately 90 minutes at 32°C. Following the 90-minute sodium fluorescein exposure, permeability was measured as the optical density at 490 nm by a spectrophotometer. The In Vitro Irritancy Score (IVIS) for the test material, vehicle control, and positive control was calculated by adding the corrected mean opacity score to fifteen times the corrected mean optical density; the IVIS for negative control was performed by adding the mean opacity score to fifteen times the mean optical density. Based on the IVIS score, the test article was classified according to the prediction model described in DB-ALM Protocol No. 127, a modification of the prediction model suggested by Gautheron, et al. (1994). The mean IVIS for the test article was -1.56. The 4-hour mean corrected opacity score was -1.66 and the corrected mean optical density score was 0.007. Controls performed as expected. Based on the IVIS score of -1.56, the test article is not considered to be an eye irritant (mean IVIS 0 to 3) in the Bovine Corneal Opacity and Permeability (BCOP) Test. 

 

Skin Irritation:

 

The in vitro skin irritation/corrosion potential of the test article (yellow solid; Lot 646729) was evaluated using the MatTek EpiDerm Skin Corrosivity Test. The study was performed in compliance with GLP. The study design was based on the MatTek MTT Effective Time-50 (ET-50) Protocol (protocol no. 711-02). The test article was prepared in tissue culture water (TCH2O). EpiDerm samples were incubated in 6-well tissue culture plates containing assay medium for 1 hour. After incubation, 25 mg of the test article plus 25 uL TCH2O were applied to the top of each EpiDerm tissue. The test article remained in contact with the tissue for 3 and 60 minutes. A negative control (50 uL of TCH2O) and a positive control (50 uL of potassium hydroxide solution, 8.0 N) were tested in parallel. Each treatment with test article or control was conducted in triplicate. At the end of the exposure period, each EpiDerm tissue was rinsed with phosphate buffer saline (PBS) and transferred to a 24-well microplate containing 300 uL of MTT solution (1 mg/mL MTT in Dulbecco's Modified Eagle's Medium (DMEM)); a negative control, 100 uL of TCH2O was tested concurrently. Tissues were then returned to the incubator for a 3-hour MTT incubation period. Following the MTT incubation period, each EpiDerm™ tissue was rinsed with PBS and then treated overnight with 2.0 ml of extractant solution (isopropanol) per well. The absorbency of an aliquot of the extracted MTT formazan was measured in triplicate at 540 nm using a microplate reader. The mean absorbance value for each time point was calculated from the optical density (OD) of the duplicate tissues and expressed as percent viability for each sample. A mean viability at 3 minutes of greater than or equal to 50% and a mean viability at 60 minutes greater than or equal to 15% indicates the material was non-corrosive. The positive and negative controls performed as expected which indicated test validity. The cell viability for tissue treated with the test material was 103.3% and 97.7% at 3 and 60 minutes, respectively. Based on the results of the study, the test material MTDID 28640 is not considered to be corrosive in the EpiDerm Skin Corrosivity Test (OECD 431). 

Justification for classification or non-classification

Based on the results of the studies, the test article not classified for eye irritation and is a Category 2 dermal irritant according to CLP.