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Diss Factsheets

Administrative data

Description of key information

Oral (OECD 423, rat): LD50 >2000 mg/kg bw (RA from CAS 16415-12-6)
Inhalation: No data available
Dermal (OECD 402, rat): LD50 >2000 mg/kg bw

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records
Reference
Endpoint:
acute toxicity: oral
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Please refer to the attached justification below and the overall justification for grouping of substances attached in IUCLID Section 13.
Reason / purpose for cross-reference:
read-across source
Key result
Sex:
male/female
Dose descriptor:
LD50 cut-off
Effect level:
5 000 mg/kg bw
Based on:
test mat.
Remarks on result:
other: CAS 16415-12-6, LPT, 2002
Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulations (EC) No 1272/2008
Conclusions:
A reliable study conducted according to the standard guideline for the Acute Toxic Class method and in compliance with GLP found the LD50 in rats to be in excess of 2000 mg/kg bw with the source substance Hexadecyltrimethoxysilane (CAS 16415-12-6). As explained in the analogue justification, it is considered that the target and the source substances are unlikely to lead to differences in acute oral toxicity potential.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
5 000 mg/kg bw
Quality of whole database:
The available information comprises an adequate and reliable study (Klimisch score 1) from a reference substance with similar structure and intrinsic properties. Read-across is justified based on common functional group(s), common precursors/breakdown products, similarities in PC/ECO/TOX properties (refer to analogue justification for further details). The selected study is thus sufficient to fulfil the standard information requirements set out in Annex VII, 8.5, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006.

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Link to relevant study records
Reference
Endpoint:
acute toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Study period:
10 - 24 Aug 2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 402 (Acute Dermal Toxicity)
Version / remarks:
(1987)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.1200 (Acute Dermal Toxicity)
Version / remarks:
(1998)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.3 (Acute Toxicity (Dermal))
Version / remarks:
(2008)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Schwabach, Germany
Test type:
standard acute method
Limit test:
yes
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River, Sulzfeld, Germany
- Age at study initiation: 10 - 11 weeks (males), 13 - 14 weeks (females)
- Weight at study initiation: 249 - 276 g (males), 200 - 209 g (females)
- Housing: animals were kept individually in IVC cages (type III H), polysulphone cages on Altromin saw fibre bedding
- Diet: Altromin 1324 maintenance diet for rats and mice, ad libitum
- Water: tap water, ad libitum
- Acclimation period: at least five days

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

IN-LIFE DATES: From: 30 Jul 2015 To: 24 Aug 2015
Type of coverage:
semiocclusive
Vehicle:
unchanged (no vehicle)
Details on dermal exposure:
TEST SITE
- Area of exposure: the test item was applied on the back of the animals
- % coverage: not less than 10% of body surface
- Type of wrap if used: the test item was held in contact with the skin with a gauze-dressing and non-irritating tape and was fixed with an additional dressing in a suitable manner

REMOVAL OF TEST SUBSTANCE
- Washing (if done): residual test item was removed by using aqua ad injectionem
- Time after start of exposure: 24 hours

TEST MATERIAL
- Amount(s) applied: 2000 mg/kg bw
Duration of exposure:
24 h
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
5
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: clinical examination was made several times on the day of dosing and once daily thereafter, weighing was performed prior to application and weekly thereafter
- Necropsy of survivors performed: yes
- Other examinations performed: Clinical examination included changes in the skin/fur, edema and erythema, eyes and mucous membranes. Also respiratory, circulatory, autonomic and central nervous systems and somatomotor activity and behaviour pattern were examined. Particular attention was directed to observations of tremor, convulsions, salivation, diarrhoea, lethargy, sleep and coma.
Key result
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Based on:
test mat.
Remarks on result:
no indication of skin irritation up to the relevant limit dose level
Mortality:
No mortalities occurred during the entire study period.
Clinical signs:
other: No signs of systemic toxicity were recorded during the entire study period.
Gross pathology:
Beside acute injection of blood vessels in the abdominal region, which is due to the euthanasia injection, no special gross pathological changes were found in any animal.
Other findings:
No erythema or edema was observed in any animal during the entire study period. Scratches were observed in 1/5 male animals, which were considered as slight signs of irritation. All signs of irritation were reversible within the observation period.

Table 1: Absolute Body Weights in g and Body Weight Gain in %

Test Group

Animal No.

Dose (mg/kg bw)

Body Weight (g) on Day

BW gain in Comparison to Day 1 (%)

Day 1

Day 8

Day 15

Day 15

 

 

Males

21

 

 

2000

 

260

265

294

13

22

249

255

277

11

23

270

280

316

17

24

276

288

321

16

25

272

280

312

15

 

 

Females

26

 

 

2000

203

204

210

3

27

206

202

218

6

28

209

212

226

8

29

206

206

214

4

30

200

200

213

7

Interpretation of results:
other: CLP/EU GHS criteria are not met, no classification required according to Regulations (EC) No 1272/2008
Conclusions:
In an acute dermal toxicity study according to OECD TG 402 and in compliance with GLP, no mortality and no clinical signs of toxicity were observed at the limit dose of 2000 mg/kg bw. Furthermore, no erythema and edema were observed within the 14 day observation period. In conclusion, a dermal LD50 value >2000 mg/kg bw was derived.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
LD50
Value:
2 000 mg/kg bw
Quality of whole database:
The available information comprises an adequate and reliable study, and is thus sufficient to fulfil the standard information requirements set out in Annex VII, 8.5, of Regulation (EC) No 1907/2006.

Additional information

No data on acute oral toxicity is avaiable for triethoxyhexadecylsilane (CAS 16415-13-7). Therefore, the risk assessment was performed based on the available data from the source substance hexadecyltrimethoxysilane (CAS 16415-12-6). In accordance with Regulation (EC) No. 1907/2006 Annex XI, 1.5 “Grouping of substances and read across” and following the Read across assessment framework (RAAF, ECHA 2017) read across from analogue substances has been applied to support the human health hazard assessment of triethoxyhexadecylsilane (CAS 16415-13-7).

 

Acute toxicity: oral

No data on acute oral toxicity is available with triethoxyhexadecylsilane (CAS 16415-13-7). Therefore, read across from the structurally analogue substance hexadecyltrimethoxysilane (CAS 16415-12-6) was applied.

A key acute oral toxicity study performed according to OECD TG 423 and in compliance with GLP with the read-across substance hexadecyltrimethoxysilane (CAS 16415-12-6) is available (LPT, 2002). Three Crl:CD rats of each sex were administered the neat test material at a single dose of 2000 mg/kg bw via oral gavage. No mortality occurred and no signs of systemic toxicity were recorded throughout the 14-day observation period. Among this, no treatment-related effects on body weight were noted and no pathological findings were observed at necropsy. Thus, the acute oral LD50 value in rats was considered to be >2000 mg/kg bw. According OECD TG 423 a LD50 cut-off value of 5000 mg/kg bw can be set.

Taking into consideration the above results generated from the structurally analogue substances the target substance triethoxyhexadecylsilane (CAS 16415-13-7) is not expected to be acute toxic via oral route. 

 

Acute toxicity: inhalation

According to Regulation (EC) No 1907/2006, Annex VIII, Section 8.5, Column 2, in addition to the oral route (8.5.1), for substances other than gases, the information mentioned under 8.5.2 to 8.5.3 shall be provided for at least one other route. As information mentioned under 8.5.3 is provided, this requirement is fulfilled by using the most appropriate route of exposure. No acute inhalation toxicity study need to be performed according to the criteria outlined in Regulation (EC) No 1907/2006, Annex VIII, 8.5.2, column 2, since the vapour pressure of the substance is very low and the possibility of human exposure is not expected under normal conditions of handling.

 

Acute toxicity: dermal

A key acute dermal toxicity study was performed with the registration substance triethoxyhexadecylsilane (CAS 16415-13-7) according to OECD TG 402 and in compliance with GLP (BSL, 2015). In this limit test five Wistar rats of each sex were exposed to a single dose of 2000 mg/kg bw of the test substance for 24 h via semi-occlusive dressing and observed for 14 days post-application. No mortalities occurred and no signs of systemic toxicity were recorded during the entire study period. A slight weight loss was recorded for 1/5 female animals during the first week, nevertheless 4/5 female animals showed weight gain during the second week. The male animals showed normal weight gain during the entire observation period. No abnormalities were observed at necropsy. Neither erythema nor edema formation was observed in any animal during the entire study period. Scratches were observed in 1/5 male animals, which were considered as slight signs of irritation. All signs of irritation were reversible within the observation period. Thus, an acute dermal LD50 value of >2000 mg/kg bw was derived.

Justification for classification or non-classification

Reliable data from a structural analogue on acute oral toxicity indicates that Triethoxyhexadecylsilane do not meet the criteria for classification according to Regulation (EC) No 1272/2008, and the available data are therefore conclusive but not sufficient for classification.

The available data on acute dermal toxicity of Triethoxyhexadecylsilane do not meet the criteria for classification according to Regulation (EC) No 1272/2008, and are therefore conclusive but not sufficient for classification.