N-{3-[dimethoxy(methyl)silyl]propyl}butan-1-amine

Endpoint summary

Description of key information

Skin corrosion (OECD TG 431): not corrosive

Skin irritation (OECD TG 439): EpiDerm: irritating; EpiSkin: not irritating

Eye irritation (OECD TG 405): causes irreversible effects to the eye (RA from CAS 3069-25-8 and CAS 31024-56-3)

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 - 18 Jan 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Version / remarks:

29 July, 2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Schwabach, Germany

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: EpiDerm™

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: reconstituted three-dimensional human skin model EPIDERM™
- Tissue batch number(s): 25874 and 25848

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1 °C
- Temperature of post-treatment incubation: 37 ± 1 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
- Volume and number of washing steps: Tissue was gently rinsed about 20 times with PBS to remove any residual test item. Excess PBS was removed by gently shaking the insert and blotting bottom with blotting paper

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT stock solution (i.e., 5 mg/mL MTT in PBS) diluted 1 + 4 with Dulbecco’s Modified Eagle Medium (DMEM)-based medium (final concentration 1 mg/mL)
- Incubation time: 3 h
- Spectrophotometer: Yes, plate spectrophotometer
- Wavelength: 570 nm
- Filter: Not reported

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
- Killed tissues: The mixture of 50 µL test item per 1 mL MTT medium showed reduction of MTT as compared to the solvent. The mixture turned blue/purple. For quantitative correction of results, the part of absorption due to the non-specific reduction of MTT (NSMTT) was determined by using killed tissues. Therefore, two tissues per treatment period were treated with the test item (KT) or left untreated (KU), respectively. NSMTT was calculated relative to the negative control of living tissues (NK) per treatment period according to the following formula:
NSMTT = [(ODKT – ODKU / ODNK] * 100

NSMTT was ≤ 30% relative to the negative control of living epidermis. In the 3 min experiment NSMTT was -18.42%, in the 60 min experiment 10.90%. This means that the test item was washed away almost completely before the addition of the MTT solution. The true MTT metabolic conversion (TODTT) of the test item treated living tissues (TM) was corrected for each treatment period according to the following formula:
TODTT = ODTM - (ODKT - ODKU)

The mixture of 50 µL test item per 300 µL Aqua dest. and per 90 µL isopropanol showed no colouring as compared to the solvent. Therefore, no additional controls for non-specific colouring potential were included.

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: 1.71 ± 0.9 for lot 25874; 1.257 ± 0.111 for lot 25848
- Barrier function: 5.28 h for lot 25874; 7.34 h for lot 25848
- Contamination: Screened for HIV-1, hepatits B and C, bacteria, yeast, and other fungi. No contaminates were detected.

NUMBER OF REPLICATE TISSUES: 2

PREDICTION MODEL / DECISION CRITERIA
A substance was considered corrosive if tissue viabilities were: a) < 50% after 3 min exposure; b) ≥ 50% after 3 min exposure AND < 15% after 60 min exposure; c). < 25% after 3 min exposure ; OR ≥ 25% after 3 min exposure. A substance was considered noncorrosive if tissue viabilities were ≥ 50% after 60 min exposure AND ≥ 15% after 60 min exposure.

The test meets acceptance criteria if:
- mean absolute OD570 nm of the two negative control tissues of every treatment period is between 0.8 and 2.8,
- mean relative tissue viability of the two positive control tissues of the 60 min treatment period is < 15%,
- coefficient of variation (CV) (in the range of 20 – 100% viability) between two tissues treated identically is ≤ 30%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount applied: 50 µL

NEGATIVE CONTROL
- Amount applied: 50 µL

POSITIVE CONTROL
- Amount applied: 50 µL

Duration of treatment / exposure:

3 min and 60 min

Number of replicates:

The test was performed on a total of 4 tissues per dose group, 2 replicates for each treatment period (3 min and 60 min exposure time).

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 min treatment

Value:

104.1

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60 min treatment

Value:

22.2

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- Direct-MTT reduction: The test item showed non-specific MTT-reducing potential.
- Colour interference with MTT: The test item showed no colour interference.

DEMONSTRATION OF TECHNICAL PROFICIENCY: The controls confirmed the validity of the study. The mean OD570nm of the two negative control tissues was ≥ 0.8 and ≤ 2.8 for each exposure period. The mean relative tissue viability (% negative control) of the positive control was < 15% (1.5%) after 60 min treatment. The coefficient of variation (CV) (in the range of 20 – 100% viability) of replicate tissues of all dose groups was ≥ 30% (20.1% - 21.8%). Tabulated test acceptance criteria and historical control data are presented in Attachment 1.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes
- Acceptance criteria met for positive control: yes
- Acceptance criteria met for variability between replicate measurements: yes

Interpretation of results:

other: non-corrosive according to Regulation (EC) No. 1272/2008

Conclusions:

Under the conditions of the conducted test, the test substance did not possess corrosive properties towards reconstructed human epidermis tissue in the EpiDerm™ model.

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

26 - 28 Sep 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

18 June 2019

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Bayrisches Landesamt für Gesundheit und Lebensmittelsicherheit, Schwabach, Germany

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: EpiDerm™-Standard Model (EPI-200™)

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: reconstituted three-dimensional human skin model EpiDerm (MatTek)
- Tissue batch number(s): 28657

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1°C
- Temperature of post-treatment incubation: 37 ± 1°C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: tissues were washed by filling and emptying the inserts 15 times with Dulbecco’s phosphate buffered saline (DPBS) using a constant stream in about 1.5 cm distance from the tissue surface, staggered again in e.g. one-minute intervals.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT stock solution (i.e., 5 mg/mL MTT in PBS) diluted 1 + 4 with Dulbecco’s Modified Eagle Medium (DMEM)-based medium
- Incubation time: 60 min
- Spectrophotometer: Yes, plate spectrophotometer
- Wavelength: 570 nm
- Filter: Yes
- Filter bandwidth: ± 30 nm

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
- 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. As the MTT reducing test item was scored as “Irritant” i.e. mean tissue viability is < 50%, no correction procedures were necessary.
- The mixture of 30 µL of the test item per 300 µl aqua dest. and per 300 µL isopropanol showed no colouring detectable by unaided eye-assessment, therefore, no correction for non-specific colour interference was necessary.

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: 2.057 ± 0.048
- Barrier function: 4.79 hrs
- Contamination: Screened for HIV-1, hepatits B and C, bacteria, yeast, and other fungi. No contaminates were detected.

NUMBER OF REPLICATE TISSUES: triplicate

PREDICTION MODEL / DECISION CRITERIA
The irritant potential was predicted from the relative mean tissue viabilities compared to the negative control. If the mean relative tissue viability is > 50% the test material is not considered an irritant. If the mean relative tissue viability is ≤ 50%, the test material is considered an irritant.

The test meets acceptance criteria if:
- mean absolute OD570 of the three negative control tissues is ≥ 0.8 and ≤ 2.8
- mean relative tissue viability of the three positive control tissues is ≤ 20%
- standard deviation (SD) of relative tissue viability obtained from each three concurrently tested tissues is ≤ 18%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 30 µL
- Concentration: undiluted

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 30 µL
- Concentration: undiluted

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 30 µL
- Concentration: 5% SDS solution

Duration of treatment / exposure:

60 min

Duration of post-treatment incubation (if applicable):

42 h

Number of replicates:

3

Irritation / corrosion parameter:

% tissue viability

Value:

11.9

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: The test item showed no visible damage to the test system.
- Direct-MTT reduction: The test item showed non-specific MTT-reducing potential, however, as the substance was scored as “Irritant”, i.e. mean tissue viability was < 50%, no correction procedures were necessary.
- Colour interference with MTT: The mixture of the test item with aqua dest. and isopropanol showed no colour interference.

DEMONSTRATION OF TECHNICAL PROFICIENCY:
The test item showed irritative effects. Positive and negative controls responded appropriately. The maximum inter-tissue viability difference of replicate tissues fell within the acceptance criteria. Positive and negative controls responded appropriately. The maximum inter-tissue viability difference of replicate tissues fell within the acceptance criteria.

ACCEPTANCE OF RESULTS (see attachment for results on the quality criteria and historical control data):
- Acceptance criteria met for negative control: The mean absolute OD570 of the three negative control tissues was ≥ 0.8 and ≤ 2.8 (1.620), meeting the acceptance criteria.
- Acceptance criteria met for positive control: The mean relative tissue viability of the positive control was ≤ 20% (3.2%).
- Acceptance criteria met for variability between replicate measurements: The standard deviation of viability of replicate tissues of all dose groups was ≤ 18% (0.3-2.8%).

Interpretation of results:

other: CLP/EU GHS criteria are met, Category 2 classification is required according to Regulations (EC) No. 1272/2008.

Conclusions:

In an in vitro skin irritation human skin model test (EpiDerm) according to OECD guideline 439 and in compliance with GLP, a cell viability of ≤ 50% was measured when compared to the untreated control. Therefore, the test item should be classified as Category 2.

Reference 3

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

26 - 28 Sep 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

18 June 2019

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, , Schwabach, Germany

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: EPISKIN-Standard Model™ (EPISKINSM™)

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN-Standard Model™
- Tissue batch number(s): 17-EKIN-026; 18-EKIN-039

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1°C
- Temperature of post-treatment incubation: 37 ± 1°C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: tissues were washed by filling and emptying the inserts 15 times with Dulbecco’s phosphate buffered saline (DPBS) using a constant stream in about 1.5 cm distance from the tissue surface, staggered again in e.g. one-minute intervals.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT stock solution was diluted 1 + 9 with DMEM-based medium (final concentration 0.3 mg/mL)
- Incubation time: 3 h
- Spectrophotometer: Yes, plate spectrophotometer
- Wavelength: 570 nm
- Filter: Yes
- Filter bandwidth: ± 30 nm

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
- The mixture of 10 µl test item per 2 mL MTT medium showed reduction of MTT as compared to the solvent. The mixture turned blue/purple. For quantitative correction of results, the part of absorption due to the non-specific reduction of MTT (NSMTT) was determined by using killed tissues. Therefore, three tissues were treated with the test item (KT) and with the negative control DPBS (KU), respectively. NSMTT was calculated relative to the negative control of living tissues (NC) according to the following formula: NSMTT [%] = [(ODKT - ODKU)/ODNC] * 100
- The calculated NSMTT was ≤ 30% (0.7%) relative to the negative control of living epidermis and could therefore be used for determination of the true MTT metabolic conversion (TODTT) of the test item treated living tissues (TM) according to the following formula: TODTT = ODTM - (ODKT - ODKU)
- The mixtures of 10 µL of the test item per 90 µL aqua dest. and per 90 µL isopropanol showed no colouring detectable by unaided eye-assessment, therefore, no correction for non-specific colour interference was necessary.

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Barrier function: 1.8 mg/mL (18 EKIN 025); 2.2 mg/mL (18 EKIN 039)
- Morphology: 22.3 ± 0.5, CV = 2.4% (17 EKIN 026); 23.3 ± 0.3, CV = 1.1% (18 EKIN 039)
- Contamination: Screened for HIV-1, hepatits B and C, bacteria, yeast, and other fungi. No contaminates were detected.

NUMBER OF REPLICATE TISSUES: Triplicate

PREDICTION MODEL / DECISION CRITERIA
The irritant potential was predicted from the relative mean tissue viabilities compared to the negative control. If the mean relative tissue viability is > 50% the test material is not considered an irritant. If the mean relative tissue viability is ≤ 50%, the test material is considered an irritant.

The test meets acceptance criteria if:
- mean OD570 nm of the blank is < 0.1
- mean absolute OD570 of the three negative control tissues is ≥ 0.6 and ≤1.5
- mean relative tissue viability of the three positive control tissues is ≤ 40%
- standard deviation (SD) of relative tissue viability obtained from each three concurrently tested tissues is ≤ 18%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 10 µL
- Concentration: undiluted

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 10 µL
- Concentration: undiluted

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 10 µL
- Concentration: 5% SDS solution

Duration of treatment / exposure:

15 min

Duration of post-treatment incubation (if applicable):

42 h

Number of replicates:

3

Irritation / corrosion parameter:

% tissue viability

Value:

71.2

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: The test item showed no visible damage to the test system.
- Direct-MTT reduction: The test item showed non-specific MTT-reducing potential.
- Colour interference with MTT: The mixture of the test item with aqua dest. and isopropanol showed no colour interference.

DEMONSTRATION OF TECHNICAL PROFICIENCY: The test item showed no irritative effects. Positive and negative controls responded appropriately. The maximum inter-tissue viability difference of replic ate tissues fell within the acceptance criteria. Positive and negative controls responded appropriately. The maximum inter-tissue viability difference of replicate tissues fell within the acceptance criteria.

ACCEPTANCE OF RESULTS (see attachment for results on the quality criteria and historical control data):
- Acceptance criteria met for negative control: The mean absolute OD570 of the three negative control tissues was ≥ 0.6 and ≤ 1.5 (0.856), meeting the acceptance criteria.
- Acceptance criteria met for positive control: The mean relative tissue viability of the positive control was ≤ 40% (25.3%).
- Acceptance criteria met for variability between replicate measurements: The standard deviation of viability of replicate tissues of all dose groups was ≤ 18% (5.7%).

Interpretation of results:

other: CLP/EU GHS criteria are not met, no classification required according to Regulation (EC) No. 1272/2008

Conclusions:

In an in vitro skin irritation human skin model test (EpiSkin) according to OECD guideline 439 and in compliance with GLP, a cell viability of > 50% was measured when compared to the untreated control. Therefore, the test item was not irritating after 15 minutes of exposure.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Remarks:

summary of available data used for the endpoint assessment of the target substance

Adequacy of study:

key study

Justification for type of information:

refer to analogue justification provided in IUCLID section 13

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not reversible

Remarks on result:

other: cornea opacity (grade 2) persisted after 21 days

Remarks:

CAS 3069-25-8, Huls AG 1989

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

not reversible

Remarks on result:

other: iridial effects (grade 1) persisted after 21 days (circumcorneal injection from day 6 until study termination)

Remarks:

CAS 3069-25-8, Huls AG 1989

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

3

Max. score:

3

Reversibility:

not reversible

Remarks on result:

other: redness (grade 2) persisted after 21 days, necrotic conjunctival sac and haw observed after 24 h

Remarks:

CAS 3069-25-8, Huls AG 1989

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

not reversible

Remarks on result:

other: chemosis (grade 1) persisted after 21 days

Remarks:

CAS 3069-25-8, Huls AG 1989

A supporting study is available with another source substance (CAS 31024-56-3). The source was tested for its eye irritating properties in a non-guideline study and without GLP compliance. Single instillation of 0.005, 0.02, 0.1, or 0.5 mL undiluted or 0.5 mL of 40, 15, 5, or 1% test material dilutions in propylene glycol were made into the conjunctival sac of 5 rabbits. Severe corneal injury with irritis from 0.05 mL undiluted test material per eye and moderate to severe corneal injury with irritis one one animal treated with 0.5 mL of 5% test material diluted in propylene glycol were oserved. No injury was observed in 5 eyes treated with 1% test material in propylene glycol. Hence, the test item was concluded to cause severe damage to the eyes.  

Interpretation of results:

other: CLP/EU GHS Category 1 (H318) according to Regulation (EC) No. 1272/2008

Conclusions:

Two eye irritation studies with the source substances CAS 3069-25-8 and CAS 31024-56-3, one conducted according to OECD 405 but not GLP, indicate that the source substances are severely irritating to the eyes of rabbits. As explained in the analogue justification, it is considered that the target and the source substances are unlikely to lead to differences in eye irritation potential.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation/corrosion:

An in vitro skin corrosion study (OECD 431, GLP compliant) with N-{3-[dimethoxy(methyl)silyl]propyl}butan-1-amine (CAS 120939-52-8) is available. In this study, a reconstituted three-dimensional human epidermis model was used. The registered substance was applied topically and cytotoxicity was expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT after a 3 min and 60 min exposure period and compared to those of the concurrent negative controls. The registered substance showed non-specific MTT-reducing potential. Therefore, additional killed tissue controls were treated with the registered substance to determine the non-specific reduction of MTT (NSMTT) and the results were corrected to the true MTT metabolic conversion (TODTT). The registered substance showed no water-colouring potential or corrosive effects. The mean relative tissue viability was 104.1% after 3 min treatment and 22.2% after 60 min treatment. Based on these effects, the registered substance showed no corrosive effects.

 

There are two in vitro skin irritation studies with the registration substance available (Eurofins 2019 a and b).

 

In the first study (Eurofins, 2019a), N-{3-[dimethoxy(methyl)silyl]propyl}butan-1-amine (CAS 120939-52-8) was investigated for skin irritation according to OECD TG 439 (EpiDerm) and in compliance with GLP. Hereby, the test item was applied topically. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT after a 60 min exposure and 42 h post-incubation period and compared to those of the concurrent negative controls. The test item showed irritant effects. The mean relative tissue viability (% negative control) was < 50% (11.9%) after 60 min treatment and 42 h post-incubation. The controls confirmed the validity of the study. The mean absolute OD₅₇₀ of the three negative control tissues was ≥0.8 and ≤ 2.8 (1.620). The mean relative tissue viability (% negative control) of the positive control was ≤20% (3.2%). Standard deviation of viability of replicate tissues of all dose groups was ≤ 18% (0.3% - 2.8%). In conclusion, in this study under the given conditions the test item showed skin irritant effects. The relative mean tissue viability after 60 min of exposure and 42 h post-incubation was ≤ 50%.

 

In the second study (Eurofins, 2019b), N-{3-[dimethoxy(methyl)silyl]propyl}butan-1-amine (CAS 120939-52-8) was investigated for skin irritation according to OECD TG 439 (EpiSkin) and in compliance with GLP. Hereby, the test item was applied topically. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT after a 15 min exposure and 42 h post-incubation period and compared to those of the concurrent negative controls. The test item showed no irritant effects. The mean relative tissue viability (% negative control) was > 50% (70.5%, NSMTT - corrected) after 15 min treatment and 42 h post-incubation. The controls confirmed the validity of the study. The mean OD570 of the six blank values was < 0.1 (0.043). The mean absolute OD₅₇₀ of the three negative control tissues was ≥ 0.6 and ≤ 1.5 (0.856). The mean relative tissue viability (% negative control) of the positive control was ≤ 40% (25.3%). The maximum standard deviation of viability of replicate tissues of all dose groups was ≤ 18% (5.7%). In conclusion, in this study under the given conditions the test item showed no skin irritant effects. The relative mean tissue viability after 15 min of exposure and 42 h post-incubation was > 50%.

 

From the study director of Eurofins we received the information that, in Eurofins' experience, the EpiSkin tissue test may not react sensitively to amines and their derivatives. Both the dermal corrosion and the positive irritation assay were carried out with EpiDerm tissue, and, therefore, this information is used to consider N-{3-[dimethoxy(methyl)silyl]propyl}butan-1-amine to be skin irritating in a worst case approach.

 

Eye irritation:

 

No data on eye irritation is available with N-{3-[dimethoxy(methyl)silyl]propyl}butan-1-amine (CAS 120939-52-8). Therefore, read across from the structurally similar source substances N-methyl-3-(trimethoxysilyl)-1-propanamine (CAS 3069-25-8) and N-[3-(trimethoxysilyl)propyl]-1-butanamine (CAS 31024-56-3) was applied. In accordance with Regulation (EC) No. 1907/2006 Annex XI, 1.5 “Grouping of substances and read across” and in accordance with the Read across assessment framework (RAAF, ECHA 2017) read across from analogue substances has been applied to support the human health hazard assessment of N-{3-[dimethoxy(methyl)silyl]propyl}butan-1-amine (CAS 120939-52-8).

 

In the available key study (Hüls AG, 1989) conducted according to the OECD TG 405, but not in compliance with GLP, 1 Small White Russian rabbit was instilled with 0.1 mL of the undiluted N-methyl-3-(trimethoxysilyl)-1-propanamine (CAS 3069-25-8) into the eye. It is not stated in the study report, whether the test item was administered into both eyes or one eye remained untreated and served as control. After 1 h severe redness and chemosis of the conjunctiva, corneal opacity grade 3 and iridic irritation grade 1 were observed. Moreover, iris reaction was delayed. Similar reactions persisted after 24 h and necrosis of the nictitating membrane and the conjunctiva was observed, in addition to strongly reddened iris in combination with haemorrhage. Treatment of the eyes with fluorescein revealed opacity of an area greater than three quarters up to the whole area. The mean scores over 24, 48, and 72 h were 2, 1, 3, and 1 for cornea, iris, redness, and chemosis, respectively. Only the noted chemosis was reversible within 21 days; all other damages were still persistent at study termination. Since the measured pH value of the test item was 12.3, only one animal was tested for acute eye irritation in this study. It can be concluded that the severe eye effects could be due to the strong alkalinity of the test substance. Based on this result, N-methyl-3-(trimethoxysilyl)-1-propanamine (CAS 3069-25-8) is considered to cause irreversible effects on the eye.

 

In the supporting study (Bushy Run Research Center, 1981) N-[3-(trimethoxysilyl)propyl]-1-butanamine (CAS 31024-56-3) was tested for its eye irritating properties in a non-guideline study and without GLP compliance. Single instillation of 0.005, 0.02, 0.1, or 0.5 ml undiluted or 0.5 ml of 40, 15, 5, or 1% test material dilutions in propylene glycol were made into the conjunctival sac of 5 rabbits. Severe corneal injury with irritis was noted from 0.005 ml undiluted test material per eye. In another dose group moderate to severe corneal injury with irritis was observed in one animal treated with 0.5 ml of 5% test material diluted in propylene glycol. No injury was observed in 5 eyes treated with 1% test material in propylene glycol. No individual scores were given in the study report. Hence, N-[3-(trimethoxysilyl)propyl]-1-butanamine (CAS 31024-56-3) was concluded to cause severe damage to the eyes.

 

In conclusion, an eye damaging potential is also considered for the target substance N-{3-[dimethoxy(methyl)silyl]propyl}butan-1-amine (CAS 120939-52-8).

Justification for classification or non-classification

The available data is reliable and suitable for classification. Based on this data, the registered substance meets the criteria for classification as Skin Irrit. 2 (H315) and Eye Dam. 1 (H318) according to Regulation (EC) No. 1272/2008.