Tall oil, maleated

Endpoint summary

Description of key information

An occular irritant and irritating to the skin. Low vapour pressure precludes inhalation exposure.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Adequate information exists to characterise the skin and eye irritation potential of distilled tall oil maleated. The maleate salts are formed when the fatty acids or rosin acid react with maleic anhydride.

The available data includes results of tests conducted using Rosin, fumarated, Rosin, maleated, Distilled tall oil, maleated (an analogue of Rosin, maleated), and fatty acids, C14-18 and C16-18-unsatd., maleated. This information is summarised below.

Skin irritation

In a primary dermal irritation study, six young adult New Zealand white rabbits were exposed to 0.5 g of Rosin, fumarated applied for 4 hours under semi-occluded contact to intact skin (Life Science Research, 1991b). Methods used in this study were compliant with current guidelines (OECD 404). Animals were then observed for a period of 72 hours post-treatment. Irritation was scored. Mean erythema and edema scores for 24 to 72 hours were observed 0 in intact rabbit skin exposed to the test material under semi-occluded contact for 4 hours. Based on these findings, Rosin, fumarated was not considered to be a skin irritant to rabbits, and presents a low skin irritation hazard.

In a key primary skin irritation test, the test material (Fatty acids, C14-18 and C16-18-unsatd., maleated) was tested (unchanged) in vitro using EPISKIN human epidermis skin construct/s. Pre-treatment, the tissues were incubated for ≥ 24 h at 37°C, 5% CO2 in air, in humidified atmosphere (>95% r.h.), in wells containing 2 mL fresh pre-warmed maintenance medium. Each treatment group - test substance (WS400104), negative control (Phosphate Buffered Saline (PBS) , 50 µL/tissue sample), positive control (5% Sodium Dodecyl Sulphate (SDS) in distilled water, 50 µL/tissue sample) comprised 3 live (viable) tissue samples placed into wells of 12 well plates containing 2 mL pre-warmed maintenance medium per well. Additionally, one live control tissue was included in the main test for determination of non specific colour % (NSC%) induced by the test material. The duration of treatment was 15 ± 0.5 minutes with the test substance, negative or positive control at room temperature (21.9-22.3°C), followed by thorough rinsing of each epidermis unit with phosphate buffered saline 1x solution (0.9%).

Post-treatment, the residual test material or positive control substance was removed by thorough rinsing of each epidermis unit with phosphate buffered saline 1x solution (0.9%). Removal of remaining PBS was done using a Pasteur pipette linked to a vacuum. Subsequently, all tissue samples were incubated for 42 ± 1 h at 37°C, 5% CO2 & >95% r.h., in wells each containing 2 mL fresh pre-warmed maintenance medium. Thereafter, tissue samples were incubated to assess cell viability, assessed by the reduction of MTT ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) for 3 hours (± 5 minutes) at 37°C , 5% CO2 & >95% r.h., in wells each containing 2 mL of 0.3 mg/mL MTT. Non-specific colour % (NSC%) determination was conducted using one additional tissue sample for 3 hours (± 5 minutes) at 37°C , 5% CO2 & >95% r.h., in wells each containing 2 mL fresh pre-warmed maintenance medium. All tissue samples were then further processed for formazan extraction by vortexing in acidic isopropanol, 500 µL/sample and then storing the vortexed samples with gentle agitation at room temperature in the dark for approximately 3 hours. Subsequently optical density was determined at 540 nm with acidified isopropanol (0.04 N HCl final concentration,6 x 200 µL) as blanks. Tissue Viability (% of Negative Control ± s.d.) for the test material was determined to be 5.5 ± 7.44 while that of the positive control was determined to be 18 ± 5.03. The assay was considered to be valid for each treatment group and based on the findings above, Fatty acids, C14-18 and C16-18-unsatd., maleated was considered to be irritating to the skin and classified as a Category 2 irritant under EU regulations.

In a key primary skin corrosion assay, the test material (Fatty acids, C14-18 and C16-18-unsatd., maleated) was tested (unchanged) in vitro using EPISKIN human epidermis skin construct/s. Each treatment group (test material, negative control, and positive controls) comprised 3 live (viable) tissue samples placed into wells of 12 well plates containing 2.2 mL pre-warmed maintenance medium per well. The test substance (WS400104), negative control (Saline (Salsol solution, NaCl 0.9% w/v), 50 µL/tissue sample), and positive control (Glacial acetic acid, 50 µL/tissue sample) groups were treated for a period of 4 hours at room temperature (18-28°C),followed by thorough rinsing of each epidermis unit with phosphate buffered saline 1x solution (0.9%). Remaining PBS was removed by use of a Pateur pipette linked to a vacuum.

This was followed by incubation of each tissue sample at room temperature (18-28°C) for 3 hours in wells each containing 2.2 mL of 0.3 mg/mL MTT. Finally the tissue samples were processed further and formazan was extracted by vortexing in acidic isopropanol, 850 µL/sample and then storing with gentle agitation at room temperature in the dark for ca. 2 hours. The absorbance was quantitatively determined at 540 nm with acidified isopropanol (6 x 200 µL) as blanks. Tissue Viability (% of Negative Control) for the test material was determined to be 76 while that of the positive control was determined to be 11. The assay was considered to be valid for each treatment group and based on the findings above, fatty acids, C14-18 and C16-18-unsatd., maleated are not considered to be corrosive to the skin.

In a primary dermal irritation study, three New Zealand White rabbits were dermally exposed to 0.5 grams of Rosin, maleated for 4 hours using a semi-occlusive dressing (Life Science Research, 1991a). Animals then were observed for 72 hours. Mean erythema and oedema scores were calculated for the 24 to 72 hour time period. Mean erythema score (24 to 72 hours) was 0.1 and mean oedema score (24 to 72 hours) was 0. In this study, Rosin, maleated was not a dermal irritant.

In a skin irritation study with Tall oil, maleated (an analogue of Rosin, maleated) six young adult New Zealand white rabbits were exposed to 0.5 g of Century PB 84 applied for 3 minutes (semi-occluded), 1 hour (occluded), or 4 hours (occluded) to intact skin (White Eagle Toxicology Laboratories, 1993). A mean erythema score of 0.33 and a mean edema of 0 were calculated 48 hours after exposure. Based on these findings, Century PB 84 (Distilled tall oil, maleated) was not considered to be a skin irritant to rabbits, and presents a low skin irritation hazard.

Eye irritation

The eye irritation potential of Rosin, fumarated was evaluated after instillation of 0.1 g into the eye of one New Zealand White rabbit (Life Science Research, 1991c). The animal was observed and then terminated 5 hours after application. After 5 hours, the substance was found to be a severe eye irritant, and further testing was therefore not warranted.

In a key isolated chicken eye assay, the potential of the test material (fatty acids, C14-18 and C16-18-unsatd., maleated) to produce ocular irritation/corrosion was tested in vitro.

 

The test material, negative control (Saline (Salsol solution, NaCl 0.9% w/v) 30 µL/cornea), and positive control (Trichloroacetic acid, 30% w/v, 30 µL/cornea) were administered intra ocular for a period of 10 seconds (from end of administration), followed by rinsing of the cornea surface with 20 mL isotonic saline/cornea at ambient temperature. Recording of corneal opacity and macroscopic morphological damage, and measurement of cornea thickness, were conducted immediately before treatment (i.e. base line recording at t = 0) and at 30, 75, 120, 180 and 240 minutes after the post-treatment rinse. The negative control and positive control results were in line with historical data. This experiment was therefore considered to be valid. Administration of the test material to isolated chicken eye was not observed to result in any corneal swelling or corneal opacity. No evidence of increase in flourescein retention or morphological damage to the cornea was observed.

 

Based on the results of this isolated chicken eye assay, fatty acids, C14-18 and C16-18-unsatd., maleated are not considered to be eye irritants.

In a key primary eye irritation study, 0.1 mL of the test material (fatty acids, C14-18 and C16-18-unsatd., maleated; undiluted) was administered to 3 male New Zealand White rabbits. The test material was placed into the conjunctival sac of one eye per rabbit (left eye) while the contralateral eye (right eye) remained untreated to serve as a control.

Residual test material was seen in the treated eyes. Therefore, the eyes were rinsed with physiological saline at 1 hour after test material instillation. Eyes were evaluated in all animals at approximately 1, 24, 48 & 72 hours and 7, 14 & 21 days after test material instillation.

Instillation of the test material induced slight initial pain (grade 2). No signs of systemic toxicity or ill health were observed through the study period and bodyweight remained unaffected by treatment with the test material. No effects on the iriis were evident during the study, and corneal lesions (opacity grade 1) were confined to one animal from 1 to 72 hours post administration, entirely disappearing thereafter. Conjunctival redness (Grade 2), chemosis (Grade 2 or 3), and discharge (Grade 2 or 3), were seen in all animals 1 hr after instillation, thereafter gradually decreasing in severity and incidence and having fully disappeared in all animals by day 21 post administration. Control eyes were without ocular findings throughout the 21 day observation period. The mean 24-, 48-, and 72-h scores for cornea, iris, conjunctival redness, and chemosis were 0.3, 0, 1.3, and 0.8, respectively.

Based on the observations of this study, fatty acids, C14-18 and C16-18-unsatd., maleated are not considered to be irritating to the rabbit eye.

 

Respiratory Tract Irritation

No studies were identified, however a low vapour pressure indicates that exposure via this route is unlikely.

Justification for selection of skin irritation / corrosion endpoint:
Based on irritancy data for the two main constituents and/or related materials

Justification for selection of eye irritation endpoint:
Based on irritancy data for the two main constituents and/or related materials

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: highly irritating

Justification for classification or non-classification

Classified Category 2 for skin irritation according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 or UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS). Classified Category 1 for eye irritation according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and UN Globally Harmonized System of Classification and Labelling of Chemicals (GHS).