hydrolysis products of 3-(triethoxysilyl)propan-1-amine

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 Jan - 09 Feb 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP - Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

BAYERISCHES LANDESAMT FÜR GESUNDHEIT UND LEBENSMITTELSICHERHEIT, Landesinstitut für Arbeitsschutz und Produktsicherheit, München, Germany

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

other: CBA/CaOlaHsD

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Winkelmann, Borchen, Germany
- Age at study initiation: 8-9 weeks
- Weight at study initiation: 16-22 g
- Housing: the animals were housed in groups of 5 in IVC cages, type II, polysulphone cages on Altromin saw fibre bedding.
- Diet: Altromin 1324 maintenance diet for rats and mice, ad libitum
- Water: tap water, acidified with sulphuric acid to a pH value of approx. 2.8
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 55 ± 10
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

25, 50 (v/v) and 100%

No. of animals per dose:

preliminary test: 2 (in test group), 1 (control)
main test: 5

Details on study design:

RANGE FINDING TESTS: to determine the highest tolerated and non-irritant test concentration, the entire dorsal surface of the ears of 2 animals was topically treated with the undiluted test substance (100%) on three consecutive days. One further animal was treated with AOO and served as control.
- Compound solubility: the test substance was dissolved in AOO (4:1 (v/v) acetone/olive oil).
- Irritation: to assess irritation, ear thickness was measured prior to the first application, approx. 48 h after the first application and shortly before sacrifice of the animals. No signs of irritation were seen at the application site in any of the treated animals during the whole study period.
- Clinical signs and body weights: no signs of systemic toxicity were observed and all animals showed the expected gain in body weight during the study.
Based on these results, 25 and 50% (v/v) and the undiluted test substance (100%) were chosen for treatment in the main study.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: ³H-methyl thymidine incorporation determined by β-scintillation
- Criteria used to consider a positive response: the test substance was regarded as a sensitiser in the LLNA if at least one concentration of the test substance resulted in a 3-fold or greater increase in ³H-methyl thymidine incorporation into lymph node cells of treated animals compared to control animals.

TREATMENT PREPARATION AND ADMINISTRATION: immediately before the first topical application, the thickness of both ears of all animals was measured. Then, the undiluted test substance or dilutions in AOO (25 µL) were topically applied once daily to the entire dorsal surface of each ear of each mouse for three consecutive days. A second measurement of the ear thickness was performed 48 h after the first topical application. On Day 6, all mice were dosed with 20 µCi ³H-methyl thymidine (³H-TdR) by intravenous injection of 250 µL of ³H-TdR solution in PBS (80 µCi/mL) into the tail vein. Approximately 5 h later, the thickness of ears was measured and animals were sacrificed. The draining auricular lymph nodes were excised, individually pooled for each animal (2 lymph nodes/animal) and collected in PBS. A single cell suspension of pooled lymph node cells was prepared by gentle mechanical disaggregation through polyamide gauze (200 mesh size). After washing the gauze with PBS, the cell suspension was pelleted by centrifugation. The supernatant was discarded and the pellets were resuspended in PBS. Afterwards, the washing procedure was repeated and each pellet was resuspended in 1 mL 5% trichloroacetic acid (TCA) at ca. 4 °C for approx. 18 h for precipitation of macromolecules. Each precipitate was once washed again, resuspended in 5% TCA and 7 mL scintillation fluid was added. After transfer in into scintillation vials, and overnight storage, the ³H-TdR-incorporation was measured in a β-counter.

Positive control substance(s):

other: p-phenylenediamine

Statistics:

Mean values and standard deviations of DPM per node and stimulation index were calculated for each group. For ear thickness, only mean values were calculated.

Positive control results:

The positive control substance p-phenylenediamine (1% in AOO) produced a stimulation index (SI) of 11.8, thus meeting the reliability criteria for the LLNA (SI > 3).

Parameter:

SI

Remarks on result:

other: The mean stimulation index values were 1.0, 1.0, 1.3 and 0.8 at treatment concentrations of 0, 25, 50 and 100%, respectively. Since all SI values were < 3, no EC3 value could be calculated.

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: see Remark

Remarks:

Two lymph nodes of each animal were pooled and DPM values were measured from the pooled lymph node cell suspensions. The measured DPM values per animal were corrected by subtracting the background DPM value (average of the measured DPM values of 5% trichloroacetic acid solutions). Treatment with 0, 25, 50 and 100% test substance in AOO resulted in mean DPM/node per group of 598.3, 570.1, 767.0 and 497.2, respectively.

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

CLP: not classified
DSD: not classified

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

The UVCB substance "hydrolysis products of 3-(triethoxysilyl)propan-1-amine" is a complex reaction product obtained from hydrolysis of 3-(triethoxysilyl)propan-1-amine in water. The test substance consists of monomers, dimers and polymers of siloxanes as well as ethanol. The concentration range of each constituent depends on the manufacturing condition (e.g. the ratio of 3-(triethoxysilyl) propan-1-amine and water). Typical concentrations of the test substance obtained from hydrolysis of an aqueous solution of 8% 3-(triethoxysilyl)propan-1-amine are described below: ca. 0.52% (w/w) 3-aminopropylsilanetriol (monomer, CAS 58160-99-9), ca. 0.7% (w/w) 1,3-bis(3-aminopropyl)disiloxane-1,1,3,3-terol (dimer), ca. 3% (w/w) hydrolysed polymers of 3-aminopropyltriethoxysilane, ca. 4.99% (w/w) ethanol (CAS 64-17-5) and ca. 90.79% water.

Hydrolysis product of 3-(triethoxysilyl)propan-1-amine (8%) was chosen for testing skin sensitisation in animals as this concentration represents a typical concentration in the manufacturing process.

A Local Lymph Node Assay with hydrolysis product of 3-(triethoxysilyl)propan-1-amine (8%) was performed in female mice according to OECD 429 (Schmid, 2012). Based on the results of a preliminary range finding test, 5 animals per group were epidermally treated (25 µL/ear) with the test substance at concentrations of 25, 50 and 100% in acetone/olive oil (4:1 v/v) for 3 consecutive days. A similar constituted group was treated with the vehicle alone and served as controls. On Day 6, all mice were injected with ³H-methyl thymidine (³HTdR) and sacrificed 5 h afterwards. The draining auricular lymph nodes were excised and pooled for each experimental group. ³HTdR incorporation in lymphocytes was measured by beta-scintillation counting. There were no deaths during the study period and no signs of toxicity or local skin irritation were noted. The mean disintegration per minute (DPM) values for the single cell suspensions of each experimental group were 598.2, 570.1, 767.0 and 497.2 at concentrations of 0, 25, 50 and 100% of the test substance in acetone/olive oil (4:1 v/v), respectively. The mean stimulation indices (SI) were 1.0, 1.3 and 0.9 for test concentrations of 25, 50 and 100%, respectively. Since all SI values were < 3, the test substance was not considered to be a skin sensitiser. Under the conditions of the test, the test substance is not skin sensitising.

Migrated from Short description of key information:
Skin sensitisation (OECD 429): not sensitising

Justification for selection of skin sensitisation endpoint:
There is only one study available.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Justification for selection of respiratory sensitisation endpoint:
Study not required according to Annex VII-X of Regulation (EC) No 1907/2006.

Justification for classification or non-classification

The available data on skin sensitisation of the test substance do not meet the criteria for classification according to Regulation (EC) No 1272/2008 and are therefore conclusive but not sufficient for classification.