541-02-6C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O1XMSXQFUHVRWGNA-UHFFFAOYSA-NDecamethylcyclopentasiloxane is an organosilicon compound.
541-02-6Metals -> Metalloid Compounds (Silicon)
Siloxane
Cosmetics ingredient -> Anticaking/Absorbents; Antioxidant; Conditioning/Emollient; Emulsifier; Fragrance; Moisturizing/Humectant; Other (Specify); Preservative/Stabilizer; Solvent
Cosmetic ingredients (Cyclopentasiloxane) -> CIR (Cosmetic Ingredient Review)
Hair conditioning; Emollient; Solvent
Sicherheitsangaben dienen nur zur Orientierung und ersetzen weder das Sicherheitsdatenblatt (SDB) des Lieferanten noch geltende Vorschriften oder eine fachliche Bewertung.
This chemical does not meet GHS hazard criteria for 97% (4427 of 4565) of all reports.
Not Classified
Aggregated GHS information provided per 4565 reports by companies from 15 notifications to the ECHA C&L Inventory.
Warning
H227: Combustible liquid [Warning Flammable liquids]
P210, P260, P280, P319, P370+P378, P403, and P501 (click each P-code to see the statement)
Chemical: Cyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10-decamethyl-
Hazard Traits - Bioaccumulation; Carcinogenicity; Environmental Persistence; Hepatotoxicity and Digestive System Toxicity; Immunotoxicity; Reproductive Toxicity
Regulation (EC) No 1935/2004 (amended)
Cyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10-decamethyl- is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Cyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10-decamethyl- are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)
REACH registered substance: Decamethylcyclopentasiloxane (EC: 208-764-9)
Restricted substance: Decamethylcyclopentasiloxane
After the siloxanes class of chemicals was designated to the Interagency Testing Committee (ITC) Priority Testing List, an industry consortium, the Silicones Environmental, Health and Safety Council of North America (SEHSC), worked in cooperation with the ITC and the U.S. Environmental Protection Agency (EPA) to sponsor a voluntary health and safety program for siloxanes. Abstracts of each research report funded through SEHSC are posted under Siloxane Research Program on the SEHSC website. The SEHSC also provides information on obtaining full copies of the reports from the EPA on this website.[Available from, as of December 15, 2009: http://www.sehsc.com/srp-research-reports.asp]
Toxicokinetic studies were performed in rats after dosing by gavage with (14)C-D5 (single dose of 1000 mg/kg bw) dissolved in different vehicles (corn oil and simethicone fluid) and as a neat material. The carrier had a significant influence on the extent of absorption of (14)C-D5. ... Half of the systemically available D5 was eliminated as unchanged D5 in exhaled air. ...
Separate 77-d fish feeding studies were conducted on the cyclic volatile methylsiloxane (cVMS) chemicals octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane with the rainbow trout, Oncorhynchus mykiss, with the determination of biomagnification factor (BMF) and lipid-adjusted BMF (BMF(L)) values as the final experimental metrics. The studies used fish food concentrations of about 500 ug/g for exposure periods of 35 d, followed by a depuration period of 42 d with clean food. ... An absence of significant fish growth during the initial depuration phase allowed for measurement of empirical depuration rate constants (k2) independent of growth dilution for D4 and D5 of 0.035 and 0.040/d, respectively, corresponding to elimination half-lives of approximately 20d.
Major metabolites of D5 were identified in urine collected from Fischer (F-344) rats administered ... (14)C-D5 orally and via intravenous injection ... The metabolites of D5 are as follows: Me(2)Si(OH)(2), MeSi(OH)(3), MeSi(OH)(2)OSi(OH)(3), MeSi(OH)(2)OSi(OH)(2)Me, MeSi(OH)(2)OSi(OH)Me(2), Me(2)Si(OH)OSi(OH)Me(2), Me(2)Si(OH)OSiMe(2)OSi(OH)Me(2), nonamethylcyclopentasiloxanol, and hydroxymethylnonamethylcyclopentasiloxane. No parent ... D5 was present in urine. The presence of certain metabolites such as ... Me(2)Si(OH)(2) ... clearly established the occurrence of demethylation at the silicon-methyl bonds. Metabolites of the linear siloxane are structurally different from that obtained for cyclic siloxane except for the commonly present Me(2)Si(OH)(2). Mechanistic pathways for the formation of the metabolites were proposed.
To assess the fate of D5 absorbed from the skin in intact animals, (14)C-D5 was applied to the dorsal surface of male and female rats. Hair at the application site was clipped prior to application and the application site was covered with a non-occlusive elastic wrap. The study was designed to permit differentiation between D5 exhaled after absorption and D5 evaporating from the application site. After application of D5, the animals were transferred to metabolic cages for the collection of urine and feces. The majority (about 85%) of the applied (14)C-D5 volatilized from the skin. After 96 hr, 0.35% of the administered D5 remained at the application site and less than 1% of the applied (14)C-activity was recovered in urine and carcass with trace levels of (14)C-activity recovered in feces, CO2 traps, and tissues. The total amount of D5 absorbed was <1%.
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DTXSID1027184CHEMBL1885178CHEBI:191092Section 8(a) of TSCA requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, exposure, and use to EPA as cited in the preamble in 51 FR 41329. Effective date: 10/12/93; Reporting date: 2/28/94.
Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Decamethylcyclopentasiloxane is included on this list. Effective date: 10/12/93; Sunset date: 6/30/98.
Not Classified
Flammable liquids - Category 4
Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Advice for firefighters: Wear self-contained breathing apparatus for firefighting if necessary.
Use water spray to cool unopened containers.
ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Remove all sources of ignition. Beware of vapors accumulating to form explosive concentrations. Vapors can accumulate in low areas.; Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.; Methods and materials for containment and cleaning up: Contain spillage, and then collect with an electrically protected vacuum cleaner or by wet-brushing and place in container for disposal according to local regulations. Keep in suitable, closed containers for disposal.
SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.
Product: This combustible material may be burned in a chemical incinerator equipped with an afterburner and scrubber. Offer surplus and non-recyclable solutions to a licensed disposal company. Contaminated packaging: Dispose of as unused product.
Precautions for safe handling: Avoid inhalation of vapor or mist. Keep away from sources of ignition - No smoking. Take measures to prevent the build up of electrostatic charge.
Appropriate engineering controls: Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday.
Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.
SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.
Eye/face protection: Safety glasses with side-shields conforming to EN166. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Handle with gloves.
Body Protection: Impervious clothing. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection: Where risk assessment shows air-purifying respirators are appropriate use a full-face respirator with multipurpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls. If the respirator is the sole means of protection, use a full-face supplied air respirator. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
TERRESTRIAL FATE: Based on a classification scheme(1), an average Koc value of 1.48X10+5 measured in three soils(2), indicates that decamethylcyclopentasiloxane is expected to be immobile in soil(SRC). Volatilization of decamethylcyclopentasiloxane from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 33.0 atm-cu m/mole(3). However, adsorption to soil is expected to attenuate volatilization(SRC). Decamethylcyclopentasiloxane is a volatile methylsiloxane(4) and is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 0.30 mm Hg at 25 °C(5). Evaporation was measured in soil studies and found to occur with rates varying with moisture content, soil type and relative humidity(6). From its use in cosmetic products, decamethylcyclopentasiloxane is reported to evaporate from skin or hair within 4-12 hours after application(7). Dimethyl siloxanes, in general, are highly resistant to biodegradation(8). Biodegradation screening tests have found decamethylcyclopentasiloxane to be very resistant to biodegradation(5). One aerobic-anaerobic sediment test determined biodegradation half-lives in excess of 800 days(5). The abiotic degradation of volatile methylsiloxanes in soil (such as decamethylcyclopentasiloxane) is thought to occur via mechanisms such as hydrolysis reactions catalyzed by the surface activity of soil clays(6). Based on degradations studies in tropical (Hawaiian) and temperate soils(6), abiotic soil half-lives of 0.11-0.19 days and 9.7-12.5 days have been estimated for these two soil types respectively(5). A soil half-live of 12.6 days has been recommended for environmental modeling purposes(9).
FIELD STUDY: Highly weathered Hawaii Wahiawa soil (21% sand, 24% silt and 55% clay) was incubated with about 40 ug of 14-C labeled decamethylcyclopentasiloxane. The samples were kept at 32, 52, 92 and 100% humidity(1). Under low humidity conditions degradation was the main method of removal from the soil. As the humidity increased volatilization was accelerated and degradation proceeded at a slower rate(1).
AQUATIC FATE: Based on a classification scheme(1), an average Koc value of 1.48X10+5(2), indicates that decamethylcyclopentasiloxane is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon a Henry's Law constant of 33.0 atm-cu m/mole(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 5.6 hours and 7.6 days, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 3.8 years if adsorption is considered(5). According to a classification scheme(6), a BCF range of 2900 to 15500 measured in fathead minnow and rainbow trout(7) suggests that bioconcentration in aquatic organisms is very high, provided the compound is not metabolized by the organism(SRC). Dimethyl siloxanes, in general, are highly resistant to biodegradation(8). Biodegradation screening tests have found decamethylcyclopentasiloxane to be very resistant to biodegradation(7). Aqueous hydrolysis half-lives of decamethylcyclopentasiloxane at 25 °C were determined to be 9.3, 351, 1590, 214 and 31.6 hours at respective pH values of 4, 5.5, 7, 8 and 9(7). Water (at pH 7 and 25 °C) and sediment half-lives of 70.4 and 3100 days have been recommended for environmental modeling purposes(9).
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), decamethylcyclopentasiloxane, which has a vapor pressure of 0.3 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase decamethylcyclopentasiloxane is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 10 days(SRC), calculated from its rate constant of 1.55X10-12 cu cm/molecule-sec at 25 °C(3). Siloxanes (such as decamethylcyclopentasiloxane) do not absorb UV light(4) and, therefore, are not expected to be susceptible to direct photolysis by sunlight(SRC). Volatile methylsiloxanes, which are primarily released or partitioned to the atmosphere(5), can be transported over long global distances, but they have a low potential for deposition to surface media in remote regions(5-7). Volatile methylsiloxanes have relatively short global residences times with the majority of global mass removed within 3 months of the end of release(5).
Safe in the present practices of use and concentration. Ingredient, concentration, and use information are available in documents discoverable at https://cir-reports.cir-safety.org
IDENTIFICATION AND USE: Decamethylcyclopentasiloxane (D5) is a cyclic siloxane used in the formulation of consumer products as well as an industrial intermediate. HUMAN EXPOSURE AND TOXICITY: The toxicokinetics of D5 after inhalation exposure were studied in human subjects (three males and two females) after inhalation of D5 at a single concentration of 10 ppm for one hour using a mouthpiece exposure system under a mixed rest/exercise scheme. During exposure, D5 concentrations in exhaled air rapidly reach a steady state between 7 and 10 ppm; after the end of the exposures, D5 levels in exhaled air rapidly declined and reached concentrations of less than 1 ppm within 20 min in most of the subjects. Concentrations of D5 in plasma increased from a baseline level of 0.15-3.3 ug/L to between 31 and 70 ug/L at the end of the inhalation exposure and rapidly declined after the end of the exposure to reach the basal levels within 24 hr after the termination of the inhalation exposure. ANIMAL STUDIES: In repeated studies in rats with subacute, subchronic and chronic inhalation exposure, mild effects on the respiratory tract typically seen after inhalation of irritating materials, increases in liver weight (28- and 90-day inhalation studies), and a small increase in the incidence of uterine adenocarcinoma (uterine tumor) in female rats (two-year inhalation chronic bioassay) were observed. The liver effects induced by D5 were consistent with D5 as a weak "phenobarbital-like" inducer of xenobiotic metabolizing enzymes and these effects are considered to be an adaptive response. Mechanistic studies to elucidate the mode-of-action for uterine tumor induction suggest an interaction of D5 with dopamine signal transduction pathways altering the pituitary control of the estrus cycle. The resulting estrogen imbalance may cause the small increase in uterine tumor incidence at the highest D5-exposure concentration over that seen in control rats. D5 was not DNA reactive or mutagenic in standard in vitro and in vivo test systems. D5 also did not induce developmental and reproductive toxicity. ECOTOXICITY STUDIES: Fathead minnows were exposed to 0.25, 0.82, 1.7, 3.6, and 8.7 ug/L D5. During the exposure of fathead minnows to D5 there were few effects seen. Egg hatching and larval fish survival and growth were normal. Juvenile fish survival and growth were good in all environmentally-relevant concentrations of D5, and were similar to control fish.
/AQUATIC SPECIES/ Chronic toxicity and bioaccumulation of decamethylcyclopentasiloxane (D5) to Hyalella azteca was examined in a series of spiked sediment exposures. Juvenile H. azteca were exposed for 28 days (chronic) to a concentration series of D5 in two natural sediments of differing organic carbon content (O.C.) and particle size composition. The chronic, LC50s were 191 and 857 ug D5/g dry weight for Lakes Erie (0.5% O.C.) and Restoule (11% O.C.) respectively. Inhibition of growth only occurred with the L. Restoule spiked sediment with a resultant EC25 of 821 ug/g dw. Lethality was a more sensitive endpoint than growth inhibition. Biota sediment accumulation factors (BSAFs, 28 day) were <1 indicating that D5 did not bioconcentrate based on lipid normalized tissue concentrations and organic carbon normalized sediment concentrations. Organic carbon (OC) in the sediment appeared to be protective, however normalization to OC did not normalize the toxicity. Normalization of D5 concentrations in the sediments to sand content did normalize the toxicity and LC50 values of 3180 and 3570 ug D5/g sand dw were determined to be statistically the same.
/AQUATIC SPECIES/ To provide toxicity and growth information on a species of relevance to the Canadian environment, ... decamethylcyclopentasiloxane (D5) /was assessed/ in a fathead minnow (Pimephales promelas) embryo to young adult assay. The test was 65 days in length, and exposed fathead minnow eggs to juveniles until near maturity (60 days post-hatch). The D5 concentrations in flow-through fish exposure aquaria were about one-third of nominal D5 concentrations. Fathead minnows were exposed to 0.25, 0.82, 1.7, 3.6, and 8.7 ug/L D5. During the exposure of fathead minnows to D5 there were few effects seen. Egg hatching and larval fish survival and growth were normal. Juvenile fish survival and growth were good in all environmentally-relevant concentrations of D5, and were similar to control fish. The two highest D5 concentrations (8.7 ug/L and 3.6 ug/L, mean measured D5) increased the condition factors of fathead minnows compared to water control and DMSO control fish. Although there were few effects of D5 in our fathead minnow study, the compound was taken up and stored in fish bodies over the 65-day exposure. The bioconcentration factor for D5 in fathead minnows was 4450, for the lowest environmentally-relevant D5 exposure water concentrations, and 4920 for all D5 exposure concentrations tested.
/OTHER TOXICITY INFORMATION/ Decamethylcyclopentasiloxane (D5) is a cyclic volatile methyl siloxane (cVMS) commonly found in commercially available products. D5 is expected to enter the terrestrial environment through the deposit of biosolids from sewage treatment plants onto agricultural fields for nutrient enrichment. Little to no information currently exists as to the risks of D5 to the terrestrial environment. In order to evaluate the potential risk to terrestrial organisms, the toxicity of a D5 contaminated biosolid in an agricultural soil was assessed with a battery of standardized soil toxicity tests. D5 was spiked into a surrogate biosolid and then mixed with a sandy loam soil to create test concentrations ranging from 0 to 4074 mg/kg. Plant (Hordeum vulgare (barley) and Trifolium pratense (red clover)) and soil invertebrates (Eisenia andrei (earthworm) and Folsomia candida (springtail)) toxicity tests were completed to assess for lethal and sub-lethal effects. Plant testing evaluated the effects on seedling emergence, shoot and root length, and shoot and root dry mass. Invertebrate test endpoints included adult lethality, juvenile production, and individual juvenile dry mass (earthworms only). Soil samples were collected over time to confirm test concentrations and evaluate the loss of chemical over the duration of a test. The toxicity of the D5 was species and endpoint dependent, such that no significant adverse effects were observed for T. pratense or E. andrei test endpoints, however, toxicity was observed for H. vulgare plant growth and F. candida survival and reproduction. Chemical losses of up to 50% were observed throughout the tests, most significantly at high concentrations.
EPA has released the first beta version (version 0.5) of the Interactive Chemical Safety for Sustainability (iCSS) Dashboard. The beta version of the iCSS Dashboard provides an interactive tool to explore rapid, automated (or in vitro high-throughput) chemical screening data generated by the Toxicity Forecaster (ToxCast) project and the federal Toxicity Testing in the 21st century (Tox21) collaboration. /The title compound was tested by ToxCast and/or Tox21 assays; Click on the "Chemical Explorer" button on the tool bar to see the data./[USEPA; ICSS Dashboard Application; Available from, as of April 22, 2015: http://actor.epa.gov/dashboard/]
Decamethylcyclopentasiloxane emissions to the environment are estimated to be 17 kilotonnes per year in Europe alone with the vast majority of the emissions being to the atmosphere and a small fraction released to wastewater(1). The concentration of decamethylcyclopentasiloxane detected in the primary settled sewage influent of the Broadholme sewage treatment plant (in the United Kingdom) in July and Aug 2010 was 9.26-10.8 ug/L(2). Landfill biogas collected from a landfill in Montreal Canada contained decamethylcyclopentasiloxane levels of 250-6226 ug/cu m(3). Decamethylcyclopentasiloxane was detected in all 8 wastewater treatment plant sludge samples collected from plants in northeastern China in 2009 at concentrations of 168-320 ng/g dry weight (mean of 280 ng/g)(4).
Adsorption studies using three soils from the United Kingdom (silt loam, sandy loam and sandy clay loam) determined decamethylcyclopentasiloxane log Koc values of 4.98-5.29 with an average log Koc of 5.17 (Koc of 1.48X10+5)(1). According to a classification scheme(2), these Koc values suggest that decamethylcyclopentasiloxane is expected to be immobile in soil.
URBAN/SUBURBAN: Decamethylcyclopentasiloxane had been detected at concentrations ranging from 0.014 to 0.06 ppbv in 3 outdoor air samples taken from outside an office building in Newark, NJ from Feb-March 1987(1). Air monitoring conducted in Toronto Canada between March 2010 and April 2011 detected mean decamethylcyclopentasiloxane concentrations of 91-140 ng/cu m with a range of 15-247 ng/cu m(2). Decamethylcyclopentasiloxane concentrations of 100-650 ng/cu m were detected in air samples collected from two sites in Zurich Switzerland during Jan and Feb 2011(3). Air monitoring conducted at urban sites in Downsview Ontario Canada, Paris France and Sydney Florida in 2009 detected decamethylcyclopentasiloxane levels of 65-280 ng/cu m(4).
INDOOR: Decamethylcyclopentasiloxane was detected in 25 different indoor environments throughout the United States with an average concentration of 0.206 ppb(1).
INDOOR: Study of Indoor air samples testing for decamethylcyclopentasiloxane from data centers in office buildings(1).[Table#5498]
RURAL/REMOTE: Air samples collected near a private home 70 km southwest Stockholm Sweden in Nov and Dec 2011 contained a mean decamethylcyclopentasiloxane concentration of 13 ng/cu m (range of 5.6-28 ng/cu m)(1). Air samples collected at the Zeppelin observatory in the remote Arctic in 2011 detected average decamethylcyclopentasiloxane concentrations of 0.73 and 2.94 ng/cu m in the late summer and early winter respectively(2). A global monitoring study that collected air samples at remote arctic sites in Canada, the US (Alaska), and Norway in 2009 found decamethylcyclopentasiloxane concentrations of 0.30-4.0 ng/cu m(3); concentration at a remote Australia site was below detection limits (0.01 ng/cu m)(3).
SOURCE DOMINATED: Decamethylcyclopentasiloxane was detected in emissions from waste plant incinerators in concentrations ranging from 0.06-0.32 ug/cu m(1). Decamethylcyclopentasiloxane was detected but not quantified in both bonded urethane carpet cushions and prime urethane carpet cushions(2). Decamethyldisiloxane was detected in two separate domestic waste sites in Munich Germany at concentrations of 0.5-1.09 and 0.40-0.53 mg/cu m(3). Decamethyldisiloxane was also detected in the respective sewage treatment plants at concentration of 8.96-9.65 and 2.75-2.81 mg/cu m, respectively(3).
/HUMAN EXPOSURE STUDIES/ The aim of this study was the quantitative determination of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in end-exhaled air to study dermal absorption of substances in PCPs. We exposed the forearm of fifteen healthy volunteers for 60 min to pure D4 or D5 and to commercial products containing D4 and D5. Inhalation uptake was kept to a minimum by keeping the forearm in a flow cabinet during dermal exposure and supplying filtered air to the breathing zone of the volunteer during the post-exposure period. End-exhaled air was collected using a breath sampler (Bio-VOC), transferred to carbograph multi-bed adsorbent tubes and analyzed by thermal desorption gas chromatography mass spectrometry (TD-GC-MS). In the end-exhaled air of non-exposed volunteers background concentrations of D4 (0.8-3.5 ng/L) and D5 (0.8-4.0 ng/L) were observed. After exposing the volunteers, the level of D4 and D5 in end-exhaled air did not or barely exceed background concentrations. At t=90 min, a sharp increase of the D4/D5 concentration in end-exhaled air was observed, which we attributed to the inhalation of the substances during a toilet visit without using inhalation protection devices. When this visit was taken out of the protocol, the sharp increase disappeared. Overall, the results of our study indicate that dermal absorption of D4 and D5 contributes only marginally to internal exposure following dermal applications. As in our study inhalation is the primary route of entry for these compounds, we conclude that its risk assessment should focus on this particular exposure route.
/ALTERNATIVE and IN VITRO TESTS/ Induction of hepatic CYP2B1/2 and CYP3A1 by D4 and D5 has been demonstrated in the rat. CAR and PXR are involved in the selective induction of CYP2B1/2 and CYP3A1, respectively. The ability of D4 and D5 to act as functional ligands for PXR and CAR was investigated in vitro utilizing reporter gene assays. Activation of PXR was investigated utilizing a HepG2 cell line stably transfected with human PXR and a reporter gene containing the enhancer/promoter region of human CYP3A. Activation of CAR was investigated utilizing HepG2 cells transiently transfected with human and rat CAR and a reporter gene construct containing human CYP2B6 promoter. D4 and D5 were added to the cell culture medium at concentrations ranging from 1 - 1000 uM. Ethanol was used as the carrier solvent. Significant increases in PXR reporter gene expression were observed at concentrations >=31 uM D4 and >= 5 uM D5. Maximal induction was observed at 125 uM D4 (about 640% increase) and 250 uM D5 (about 460% increase). D4 induced significant increases in rat and human CAR reporter gene expression at concentrations of 5 - 250 uM and 1 - 250 uM, respectively. Maximum induction for each was 62 uM with increases of about 5- and 11-fold, respectively. D5 induced a significant trend of increasing rat CAR reporter gene expression with a maximum increase of about 175% at 250 uM. Individual dose-groups, although elevated above the control, were not statistically different from the control. Similarly, increases in human CAR activation were apparent with increasing dose, achieving statistical significance at 62 (about 600% increase) and 250 uM D5 (about 450% increase). D4 and D5 demonstrated the ability to relieve androstenol-induced repression of rat CAR. These data suggest that D4 and D5 are functional ligands for PXR and CAR consistent with their phenobarbital-like activity.
Fish collected from Lake Erie during the fall/summer months of 2009 (common shiner, yellow perch, emerald shiner, trout perch, white perch freshwater drum and walleye) contained mean decamethylcyclopentasiloxane concentrations of 14-36 ng/g wet weight and 179-386 ng/g lipid(1). Smelt and brown trout collected from Lake Mjosa Norway in Sept-Oct 2010 contained nmean decamethylcyclopentasiloxane concentrations of 18700 and 4000 ng/g lipid respectively(1). Fish collected from the Oslofjord Norway during a 2010 study (Atlantic herring, coalfish, commond sole, Norway pout, European hake, starry skate, haddock, pollock, cod) contained mean decamethylcyclopentasiloxane concentrations 43.4-1435.4 ng/g wet weight and 1455-26106 ng/g lipid(1). Flounder samples collected from six sites in the lower Humber estuary in England in 2009 contained decamethylcyclopentasiloxane concentrations of 12-269 ng/g wet weight(2). Herring (Clupea harengus) collected off the Sewdish coast in 2007 contained decamethylcyclopentasiloxane concentrations of 15-720 ng/g lipid wet(3).
Decamethylcyclopentasiloxane's production and use as an intermediate in the manufacture of high molecular weight siloxane polymers and as a carrier ingredient in personal care products(1) may result in its release to the environment through various waste streams(SRC). Its use as a volatile excipient in cosmetic products such as skin care products, deodorants/antiperspirants, hair care products and make up products will result in its direct release to the environment through evaporation(2). Decamethylcyclopentasiloxane emissions to the environment are estimated to be 17 kilotonnes per year in Europe alone with the vast majority of the emissions being to the atmosphere and a small fraction released to wastewater(3). As a result of its volatility, some 90% of the decamethylcyclopentasiloxane used in personal care products evaporates and becomes dispersed and degraded in the atmosphere(4).
Section 8(a) of TSCA requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, exposure, and use to EPA as cited in the preamble in 51 FR 41329. Effective date: 10/12/93; Reporting date: 2/28/94.
Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Decamethylcyclopentasiloxane is included on this list. Effective date: 10/12/93; Sunset date: 6/30/98.
Octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) are cyclic siloxanes used as chemical intermediates with some applications in consumer products. The in vitro percutaneous absorption of (14)C-D4 and (14)C-D5 was studied in flow-through diffusion cells. Single doses were applied neat and in antiperspirant formulations to dermatomed human skin for 24 hr. The majority of applied D4 and D5 (approximately 90%) volatilized before being absorbed. Only 0.5% of applied D4 was absorbed while the absorption of D5 (0.04%) was one order of magnitude lower. The largest percentage (>90%) of the absorbed D4 and D5 was found in the skin. The fate of D4 and D5 absorbed in the skin was studied in rat in vivo. A single dose of (14)C-D4 (10, 4.8 and 2 mg/sq cm) and (14)C-D5 (10 mg/sq cm) was topically applied inside a dosing chamber attached to the dorsal area. Rats were housed in metabolism cages up to 24 hr to enable collection of urine, feces, expired/escaped volatiles. The majority of applied D4 or D5 had volatilized from the skin surface. Less than 1.0% of the applied D4 and only 0.2% of applied D5 was absorbed with approximately 60% of absorbed D4 and 30% of absorbed D5 reaching systemic compartments. The amount absorbed into the skin decreased with time showing that residual D4 and D5 diffused back to the skin surface and continued to evaporate. Overall, a low tendency to pass through the skin into systemic compartments was demonstrated for both D4 (< or = 0.5% of applied dose) and D5 (<0.1% of applied dose).
Toxicokinetic studies were performed in rats after dosing by gavage with (14)C-D5 (single dose of 1000 mg/kg bw) dissolved in different vehicles (corn oil and simethicone fluid) and as a neat material. The carrier had a significant influence on the extent of absorption of (14)C-D5. After administration of neat D5, approximately 10% of the dose was absorbed from the gastrointestinal tract. Based on blood area under the curve (AUC), absorption increased after administration of D5 in corn oil and decreased after administration in simethicone fluid. Elimination half-lives for D5-associated radioactivity in blood ranged from 45 (simethicone) to 240 hr (corn oil), and were between 117 (neat) and 242 hr (simethicone) for parent D5. The radioactivity eliminated in the urine consisted entirely of polar metabolites of D5. Mass balance analysis indicated that approximately 60-80 % of the administered D5 was excreted unchanged in the feces, and up to 20% of administered D5 as water soluble metabolites in urine. Half of the systemically available D5 was eliminated as unchanged D5 in exhaled air. However, the kinetics and tissue distribution observed after oral dosing were qualitatively different from the distributions after inhalation or dermal exposures. Higher relative concentrations of D5 were noted in liver and spleen as compared to exposure to D5 by inhalation and dermal application.
Separate 77-d fish feeding studies were conducted on the cyclic volatile methylsiloxane (cVMS) chemicals octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane with the rainbow trout, Oncorhynchus mykiss, with the determination of biomagnification factor (BMF) and lipid-adjusted BMF (BMF(L)) values as the final experimental metrics. The studies used fish food concentrations of about 500 ug/g for exposure periods of 35 d, followed by a depuration period of 42 d with clean food. The fish tissue concentrations of D4 and D5 achieved empirical steady-state by day 21 in each study. By day 7 of exposure, total (14)C activity of both compounds had moved from the fish gastrointestinal (GI) tract into surrounding tissue. An absence of significant fish growth during the initial depuration phase allowed for measurement of empirical depuration rate constants (k2) independent of growth dilution for D4 and D5 of 0.035 and 0.040/d, respectively, corresponding to elimination half-lives of approximately 20d. These rate constants indicated that about 70-75% of steady-state was achieved during exposure in both studies, resulting in empirical steady-state BMF and BMF(L) values of 0.28 and 0.66 for D4, respectively, and 0.32 and 0.85 for D5, respectively. Kinetic modeling using simple first-order uptake and depuration dynamics produced good agreement with experimental data, with D4 and D5 assimilation efficiencies of 40% and 44%, respectively. Growth-corrected depuration rate constants modeled over the entire study data set indicated slower elimination kinetics for D4 (k2 of 0.007/d or half-life of 100 d) compared to D5 (k2 of 0.010/d or elimination half-life of 69 d). Kinetic BMFk values (i.e., k1/k2) for D4 and D5 were 1.7 and 1.3, respectively, with lipid-adjusted BMFk(L) values of 4.0 and 3.4, respectively.
For more Absorption, Distribution and Excretion (Complete) data for DECAMETHYLCYCLOPENTASILOXANE (13 total), please visit the HSDB record page.
CIR ingredient: Cyclopentasiloxane
Used as a carrier in personal care products, as a dry cleaning solvent, and to make siloxane polymers; [Merck Index]
Dry Cleaning [Category: Clean]
Intermediate in the manufacture of high molecular weight siloxane polymers. Carrier ingredient in personal care products; dry cleaning solvent.
Field of application: Fuel additives; surface treatment, cleaning/washing agents; fillers; impregnation material; adhesives; binding agents; paints; laquers and varnishes; reprographic agents; softeners; surface active agents; process regulators. /From table/
Commonly used as volatile excipient in cosmetic products including antistatic, emollient, humectant, solvent, viscosity controlling and hair conditioning ... The main use of D5 in cosmetic products is in skin care products, deodorants/antiperspirants, hair care products and make up products.
2023: 100,000,000 - <250,000,000 lb
(1981) Silicone fluids, 252 million lbs; silicone resins, 17 million lbs; and silicone elastomers, 106 million lbs.
(1986) >10 million-50 million pounds
(1990) >10 million-50 million pounds
(1994) >10 million-50 million pounds
For more U.S. Production (Complete) data for DECAMETHYLCYCLOPENTASILOXANE (8 total), please visit the HSDB record page.
Isolated from the hydrolysis product of dimethyldichlorosilane.
Acid hydrolysis of dimethyldichlorosilane gives a hydrolysate mixture of linear and cyclic polysiloxanes with decamethylcyclopentasiloxane as one cyclic component.
Cosmetics product ingredient: Decamethylcyclopentasiloxane (D5) (Cyclopentasiloxane)
Information on 740 consumer products that contain Cyclopentasiloxane in the following categories is provided:
Fragrance Ingredients
Cosmetics -> Hair conditioning; Emollient; Solvent
All Other Basic Inorganic Chemical Manufacturing
Cyclopentasiloxane, 2,2,4,4,6,6,8,8,10,10-decamethyl-: ACTIVE
Cyclomethicone is a generic name for several cyclic dimethyl polysiloxane compounds ... it refers not only to octamethylcyclotetrasiloxane (D4), but also to cyclotrisiloxane (D3), cyclopentasiloxane (D5), cyclohexasiloxane (D6), and cycloheptasiloxane (D7), i.e. compounds of the general formula (CH3)2n-(O)n-(Si)n where n = 3-7.
VerwendenOctamethylcyclotetrasiloxane and decamethylcyclopentasiloxane are major industrial products, which are either marketed as such or used for the production of polydimethylsiloxanes.
/ALTERNATIVE and IN VITRO TESTS/ The potential for D4 and D5 to act as progesterone receptor ligands was investigated in a series of in vitro assays. This effort reflects part of an initiative to explore potential modes of action related to uterine lesions identified in recently conducted chronic bioassays. The HitHunter progesterone receptor assay was used to evaluate D4 and D5 binding to recombinant human progesterone receptor-alpha. Receptor binding was evaluated also in classical radioligand binding assays that utilized recombinant human progesterone receptor-beta and cytosol from calf uterus as the source of receptor. In addition PR CALUX Bioassay, a commercially available reporter gene assay, was used to evaluate D4 and D5 as functional ligands for recombinant human progesterone receptor-beta. Ethanol was used as the carrier in each assay. D4 and D5 were evaluated over a nominal concentration range of 0.1 - 1000 uM in the HitHunter progesterone receptor assay. Receptor binding was not observed. Evaluation of receptor binding in the classical radioligand binding assays used promogestone ([3H]R-5020) as the radioligand and nominal concentration ranges of 10 - 3200 uM D4 and 10 - 2500 uM D5. There was no evidence of receptor binding. Similarly, there was no evidence of induction of reporter gene expression by D4 or D5 in the PR CALUX bioassay over the nominal concentration range of 10(-12) - 10(-3) M. These data suggest that D4 and D5 are not progesterone receptor ligands. This conclusion is in agreement with the lack of evidence for progesterone receptor activation by D4 and D5 in previously conducted rat reproductive toxicity studies in vivo.