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EC number: 239-311-3
CAS number: 15267-95-5
Oral: no data availableInhalation (OECD 413, RA from CAS 2530-87-2, rat): NOAEC=810.32 mg/m³Dermal: no data available
In addition to the 90 -day study a screening study according to OECD 422
is available as well.
Exposure to the source substance (3-Chloropropyl)trimethoxysilane up to
and including the high concentration of 100 ppm did not result in any
signs of general toxicity of the test item. Based on these results of
the OECD 422 the NOEC (no observed effect concentration) was established
as 100 ppm (nominal concentration, corresponding to 99.7 ppm mean
analytical concentration and equivalent to 810.32 mg/m³).
are no studies available for the registered substance
(chloromethyl)triethoxysilane (CAS 15267-95-5). However, reliable data
are available for the structural analogue substance
(3-chloropropyl)trimethoxysilane (CAS 2530-87-2). The read-across is
justified as follows:
dose toxicity: inhalation
the available key study (Dow Corning Corporation, 1993), conducted
according to OECD 413 and in compliance with GLP, groups of 10
Sprague-Dawley rats per sex were exposed to the test item
(3-chloropropyl)trimethoxysilane (CAS 2530-87-2) in a whole-body
inhalation system at target concentrations of 0.5, 5, and 100 ppm
(corresponding to 0.5, 5, and 99 ppm actual overall mean exposure
concentrations) for 6 hours/day, 5 days/week. After 13 weeks of
exposure, rats were sacrificed and examined for changes in blood, serum
chemistry, urine, organ weights and gross and histopathology. At 24 and
48 hours post-exposure, bone marrow was collected from the femur of 5
animals in all groups for a micronucleus assay. An additional group of
ten male and ten female rats exposed to a target concentration of 200
ppm (corresponding to 189 ppm actual overall mean exposure
concentration) were used for the micronucleus assay only, performed on
this group at 24 and 48 hours post-exposure.
examinations at study termination did not reveal any adverse findings in
females exposed to 0.5 or 5 ppm. Eight of 10 male animals in the 0.5 ppm
exposure group were reported as normal. The two remaining male animals
exhibited minimal chronic cystitis of the urinary bladder. Nine of 10
male animals were reported as normal in the 5.0 ppm exposure group. The
remaining male animals exhibited minimal chronic cystitis of the urinary
bladder. Treatment-related histopathological effects were observed in
the 100 ppm group animals. Increased incidence of hyperplasia of the
urinary bladder epithelium was noted in both sexes of this group: two
males and two females showed minimal hyperplasia, two males and 4
females showed mild hyperplasia. None of the animals showed moderate or
marked hyperplasia. The minimal and mild hyperplasia was associated in
all animals with a minimal cystitis. No clinical symptoms or change of
urine parameter were associated with these findings. The epithelium of
the normal urinary bladder of rats consists of three cell layers.
Lesions may be classified as mild hyperplasia when the epithelium
averages four cell layers in thickness, as moderate hyperplasia when it
averages five to six cell layers, and marked hyperplasia when it
averages seven or more cell layers.
to these criteria for hyperplasia a differentiation between minimal and
mild hyperplasia is not possible. Maybe minimal means in the 90 days
study that the pathologists were not convinced and it appeared that
there would be sometimes four cell layers.
it is not mentioned in the study whether the urinary bladder of the rats
was inflated to its normal size or slightly larger with a fixative
before microscopical examination. Microscopic examination of urinary
bladders which have not been inflated may lead to a misdiagnosis of
hyperplasia, due to the infoldings of the urinary bladder. Without
inflation of the urinary bladder objective evaluation of minimal/mild
hyperplasia is difficult. This eventually could explain why in the
supporting study (conducted according to OECD 422) where animals were
exposed only 28 days to substance (3-chloropropyl)trimethoxysilane (CAS
2530-87-2) no hyperplasia of the urinary bladder was reported at the
same exposure concentration (RCC, 2005).
recovery group was included in the 90 day study. Without a recovery
group we have no clarity concerning the question of reversibility of the
effects. If the hyperplasia is not reversible these proliferative
changes could indicate a urinary bladder carcinogen. However, the
overall evaluation of the genotoxicity data does not support this
mechanism. Furthermore, the hyperplasia was in all cases associated with
a minimal inflammation. Inflammatory response of the bladder (cystitis)
associated with the administration of xenobiotics is characterized by
the presence of inflammatory cells in the epithelial wall of the
bladder. This indicates that the applied substance in this study caused
a minimal injury of the bladder that caused minimal inflammation.
likely the urothelium responded with an increase in mitosis, resulting
in a minimal /mild hyperplasia. If the inflammatory stimulus
(Xenobiotic) is removed, the hyperplastic changes are expected to
regress and the urinary bladder returns to normal histologic appearance.
Therefore, the mild/minimal hyperplastic effects are not considered as
adverse and the NOAEC was set at 100 ppm (nominal concentration,
corresponding to an actual overall mean exposure concentration of 99
supporting study is available for the structural analogue substance (3
-chloropropyl)trimethoxysilane (CAS 2530 -87 -2). The study was
conducted according to OECD 422, and in compliance with GLP (RCC, 2005).
Groups of 10 Sprague-Dawley rats per sex per dose were exposed to the
vapour in a whole body inhalation system at doses of 5, 25 and 100 ppm
(corresponding to 5.02, 25.44, and 99.7 ppm mean analytical
concentration). Untreated animals served as controls. Treatment was
carried out for 6 hours daily to male rats for 28 days and to female
rats throughout the 14-day pre-pairing, pairing and gestation period
until the individual day 19 post coitum. During the pairing period, rats
were housed overnight with one male and one female in Makrolon pairing
cages. The female was placed with the same male until mating occurred or
two weeks elapsed. Animals were observed for mortalities and clinical
signs, and detailed clinical observations were performed once per week.
A Functional Observational battery (modified Irwin screen test) was
performed once during the test (males: shortly before sacrifice;
females: on day 3 post-partum). Body weights and food consumption was
recorded. Parental generation males were sacrificed after they had been
treated for 28 days, parental generation females were sacrificed on day
4 post-partum. A complete gross necropsy was performed on all adult
animals. The litters were examined for litter size, live birth,
stillbirth and any gross anomalies. The sex ratio of the pups was
recorded. Pups were weighed individually on day 0, 1 and 4 post-partum.
The pups were observed daily for survival and behavioural abnormalities
in nesting and nursing. Dead pups and pups killed on day 4 post-partum
were examined macroscopically. No test item-related mortalities or
clinical signs that were attributable to exposure to the test item were
noted throughout the study. Neither food consumption nor body weight
development were affected by exposure to the test item at any
concentration. None of the parameters under investigation during the
functional observational battery was considered to be affected by
exposure to the test item. During necropsy of parent animals no test
item-related findings were noted. Mean absolute organ weights as well as
organ/body weight ratios and organ/brain weight ratios were not affected
by exposure to the test item. There were no findings which distinguished
test item-treated animals from controls. Based on the absence of any
findings the NOAEC was set at 100 ppm (nominal concentration,
corresponding to 99.7 ppm mean analytical concentration).
available studies result in a NOAEC of 100 ppm nominal vapour
concentration. Since the key study was conducted with the longest study
duration, this result will be used for the hazard assessment. Thus, a
NOAEC of 99 ppm as actual overall mean exposure concentration will be
deduced, corresponding to 806 mg/m³.
The available data are reliable and suitable
for classification. Based on these data, classification for toxicity
after repeated exposure according to EC/1272/2008 is not warranted.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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