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Description of key information

In the key in vitro skin irritation study, conducted according to OECD TG 439, and in compliance with GLP, the mean relative tissue viability (% negative control) was <50% (10.9%) for 3,3’-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine after 15 minutes exposure and 42 hours post-incubation period (Eurofins, 2016a). Appropriate negative and positive controls were included and gave the expected results.

In the second key in vitro skin irritation study, conducted according to OECD 439 and in compliance with GLP, , reported mean relative tissue viability (% negative control) was =< 50 % (5.3%) for 3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine in EpiDermTM after 60 min treatment and 42 hours post incubation (Eurofins, 2016c).Appropriate negative and positive controls were included and gave the expected results.

In the key in vitro skin corrosion study, conducted according to OECD TG 431, and in compliance with GLP, the reported mean tissue viability for 3,3’-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine was >35% (70%) and <35% (11%) after 3-minute and 4-hour exposure, respectively. Appropriate negative and positive controls were included and gave the expected results (Eurofins, 2016b).

In the key eye irritation study, conducted according to a protocol similar to OECD 405 with acceptable restrictions and in compliance with GLP, the test material 3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine, was concluded to be Category 1 eye irritant (IRDC, 1985).

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

In the key in vitro skin irritation study, conducted according to OECD TG 439, and in compliance with GLP, the mean relative tissue viability (% negative control) was < 50% (10.9%) for '3,3’-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine after 15 minutes exposure and 42 hours post-incubation period (Eurofins, 2016a). Appropriate negative and positive controls were included and gave the expected results.

10μL of undiluted test item was applied on EpiSkin (SM) tissue for 15 min +/- 0.5 min. Following treatment, the tissues were incubated at 37 ± 1 °C, 5.0% CO2 for 42 ± 1 h. Then, determination of cytotoxic effect with MTT assay was performed and the tissues were incubated with MTT medium for 3 hours. Afterwards a total biopsy of the epidermis using the special biopsy punch was performed and the epidermis was separated from the collagen matrix. Extraction was performed and OD was measured at 570 nm. 10 μL DPBS was used as negative control and 10 μL 5% SDS solution - as positive control. Triplicate tissues were used for each dose.

The test item showed reduction of MTT as compared to the solvent. Thus, for quantitative correction of results was, the non-specific reduction of MTT was determined by using killed tissues. The mean tissue viability was 10.9% (% negative control). The controls confirmed the validity of the study. It was concluded that the substance was either corrosive or irritant to the skin, so an in vitro skin corrosion study was carried out.

In the second key in vitro skin irritation study, conducted according to OECD 439 and in compliance with GLP, , reported mean relative tissue viability (% negative control) was =< 50 % (5.3%) for 3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine in EpiDermTM after 60 min treatment and 42 hours post incubation (Eurofins, 2016c).Appropriate negative and positive controls were included and gave the expected results.

30μL of undiluted test item was applied on EpiDerm(SM) tissue for 60 min. Following treatment, the tissues were incubated at 37 ± 1 °C, 5.0% CO2 for 42 ± 1 h. Then, determination of cytotoxic effect with MTT assay was performed and the tissues were incubated with MTT medium for 3 hours. Afterwards a total biopsy of the epidermis using the special biopsy punch was performed and the epidermis was separated from the collagen matrix. Extraction was performed and OD was measured at 570 nm. 30 μL DPBS was used as negative control and 30 μL 5% SDS solution - as positive control. Triplicate tissues were used for each dose.

The mixture of 30 µL test item per 1 mL MTT medium showed reduction of MTT compared to the solvent. The mixture turned blue/purple.

The mixture of 30µL of the test item per 300 µL aqua dest. showed no colouring detectable by unaided eye assessment. Since the test item showed clear irritant potential, no correction was performed.

In the key in vitro skin corrosion study, conducted according to OECD TG 431, and in compliance with GLP, the reported mean tissue viability for '3,3’-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine was > 35% (70%) and < 35% (11%) after 3-minute and 4-hour exposure, respectively. Appropriate negative and positive controls were included and gave the expected results (Eurofins, 2016b). It was concluded that the substance was corrosive to the skin.

50 ± 3 μL of undiluted test item was applied on EpiSkin (SM) tissue for 3 min, 60 min and 4 hours. Following treatment, the tissues were incubated with MTT medium for 3 h ± 15 min at 37 ± 1 °C, 5.0% CO2 / 95% air. Afterwards a total biopsy of the epidermis using the special biopsy punch was performed and the epidermis was separated from the collagen matrix. Extraction was performed and OD was measured at 570 nm. 50 μL 0.9% NaCl solution and 50 μL glacial acetic acid were used as negative and positive controls, respectively. Duplicate tissue constructs were used per dose.

The test item showed reduction of MTT as compared to the solvent. Thus, for quantitative correction of results was, the non-specific reduction of MTT was determined by using killed tissues. The mean tissue viability was 70% after 3-minute exposure and 11% after 4-hour exposure. The controls confirmed the validity of the study.

Two supporting in vivo skin irritation studies were available. One confirmed the findings of the key studies and the test material to be corrosive to skin (Shepard, 1968). The second supporting skin irritation study, conducted according to a protocol similar to OECD 404 with acceptable restrictions and in compliance with GLP, the test material, 3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine, was concluded to be Categorry 2 irritant.

In the key eye irritation study, conducted according to a protocol similar to OECD 405 with acceptable restrictions and in compliance with GLP, the test material 3,3'-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine, was conncluded to be Category 1 eye irritant (IRDC, 1985).

Following a single instillation into the eyes of two rabbits, grade 4 corneal opacity, grade 2 iritis, grade 3 conjunctivitis and grade 4 chemosis were observed in all the animals at 24, 48 and 72 hours post-instillation, when the eyes were unwashed. Puruloid discharge, petechiea, blanching and eschar present on palpebral conjunctiva were observed in all the animals at 24, 48 and 72 h observation period.

Justification for classification or non-classification

Based on the available data for 3,3’-(1,1,3,3-tetramethyldisiloxane-1,3-diyl)bispropylamine, the substance is classified as corrosive (Category 1B) "H314: Causes severe skin burns and eye damage" according to Regulation (EC) No 1272/2008.