Dodecamethylcyclohexasiloxane

444.92

444.92

208-762-8

XHK3U310BA

DTXSID6027183

Oily liquid|Clear, siloxane fluid

29319090

55.4

8.87

Liquid

0.9672 g/cm³ @ Temp: 20 °C

-3 °C

245 °C

>76°C

1.431

In water, 0.0051 mg/L at 23 deg C

Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place. Storage class (TRGS 510): Combustible liquids.

0.0169 mm Hg at 25 deg C

Odorless

Henry's Law constant = 25.0 atm-cu m/mole at 25 °C

Molar volume = 436.8 cu cm/mol at 23 °C|Hydroxyl radical reaction rate constant = 1.80X10-12 cu cm/molecule-sec at 25 °C (est)

Enthalpy of vaporization: 56.1 to 62.6 kJ/mol

Critical temperature: 655.4 K at 12.9 atm

UN 1993C 3 / PGIII

3

36/37/38

26-36/37/39

GW2328550

Stable under recommended storage conditions.

P264, P273, P280, P305+P351+P338, P337+P313, P501

H319

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.

Incompatible materials: Strong oxidizing agents.

Safety assessment of cyclomethicone, cyclotetrasiloxane, cyclopentasiloxane, cyclohexasiloxane, and cycloheptasiloxane. Johnson W Jr et al; Int J Toxicol 30 (6 Suppl): 149S-227S (2011)

|Warning|H319 (26.92%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]|P264, P273, P280, P305+P351+P338, P337+P313, and P501|Aggregated GHS information provided by 397 companies from 7 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.|H227: Combustible liquid [Warning Flammable liquids]|P210, P280, P370+P378, P403+P235, and P501

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).

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. 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.; 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.

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.

A study focused on determining environmental presence of cyclic dimethyl siloxanes in the Scandinavia region detected dodecamethylcyclohexasiloxane in influent, effluent (treated/untreated) and industrial wastewater at a concentration range of <0.02 and 3.7 ug/L(1). It was detected in all 14 biologically digested sewage sludge samples with a total concentration of 26,000-30,000 ng/g dry weight. Dodecamethylcyclohexasiloxane was found at a concentration range of 220-11,000 ng/g dry weight(1). In Southwestern Ontario, Canada dodecamethylcyclohexasiloxane was detected in sewage treatment plant influents and effluents 0.49-27.33 ug/L and 0.97-2.71 ug/L, respectively(2). Dodecamethylcyclohexasiloxane was detected in all 8 wastewater treatment plant sludge samples collected from plants in northeastern China in 2009 at concentrations of 87.5-569 ng/g dry weight (mean of 179 ng/g)(3).

SEDIMENT: Dodecamethylcyclohexasiloxane was detected in surface sediments sampled from Lake Ontario (Toronto Harbor in July 2006 at a concentration of 0.2 ug/g dry weight, Kingston Basin, <0.01 ug/g dry weight) and in sediment cores (Rochester, Missisanuga and Niagra basins <0.01 ug/g dry weight). In October 2007 surface sediments found <19.0 ng of dodecamethylcyclohexasiloxane from Lake Opeongo, Algonquin Provincial Park Ontario, Canada(1). A study focused on determining environmental presence of cyclic dimethyl siloxanes in the Scandinavia region detected dodecamethylcyclohexasiloxane as well as other cyclic dimethyl siloxanes in sediments throughout the region. The concentration of dodecamethylcyclohexasiloxane ranged from <1-170 ng/g dry weight. The maximum cyclic dimethyl siloxane concentration detected was 2,000 ng/g at Roskilde, Denmark while all other concentrations were 15 times lower with the next highest being from Essingen in Stockholm, Sweden at 130 ng/g dry weight(2). Sediment samples collected from six sites in the lower Humber estuary in England in 2009 contained dodecamethylcyclohexasiloxane concentrations of 30-109 ng/g dry weight(3). Twenty-five sediment samples collected from various sites of the Songhua River, China in 2009 contained dodecamethylcyclohexasiloxane concentrations of 1.52-527 mg/g with a mean concentration of 76.1 mg/g(4). Sediments collected from the Oslofjord Norway during a 2010 study contained mean dodecamethylcyclohexasiloxane concentrations of 25.7-29.3 ng/g wet weight(3).

URBAN/SUBURBAN: Air monitoring conducted at urban sites in Downsview Ontario Canada, Paris France and Sydney Florida in 2009 detected dodecamethylcyclohexasiloxane levels of 4.0-53 ng/cu m(1). Outdoor air samples collected from various sites in Iowa contained dodecamethylcyclohexasiloxane concentrations <1.4-18 ng/cu m(2). Air monitoring conducted in Toronto Canada between March 2010 and April 2011 detected mean dodecamethylcyclohexasiloxane concentrations of 7.3-11 ng/cu m with a range of 1.9-22 ng/cu m(3).|INDOOR: A field study in Sweden collected indoor air samples in 400 homes as a part of the Dampness in Buildings and Health (DBH) study. The samples were taken in children's bedrooms. The results showed the presence of several siloxanes including dodecamethylcyclohexasiloxane in 142 of the 400 homes at a mean concentration of 7.9 ug/cu m and a range of 0.6 ug/cu m to 164 ug/cu m(1). Indoor air samples collected from various sites at the University of Iowa contained dodecamethylcyclohexasiloxane concentrations <59-2800 ng/cu m(2).|RURAL/REMOTE: A global monitoring study that collected air samples at remote arctic sites in Canada, the US (Alaska), and Norway in 2009 found dodecamethylcyclohexasiloxane concentrations of 0.13-1.5 ng/cu m(1); concentration at a remote Australia site was below detection limits (0.01 ng/cu m)(1). Air samples collected near a private home 70 km southwest Stockholm Sweden in Nov and Dec 2011 contained a mean dodecamethylcyclohexasiloxane concentration of 1.0 ng/cu m (range of 0.48-2.7 ng/cu m)(2). Air samples collected at the Zeppelin observatory in the remote Arctic in 2011 contained average decamethylcyclopentasiloxane concentrations of 0.23 and 0.45 ng/cu m in the late summer and early winter, respectively(3).|SOURCE DOMINATED: A study focused on determining environmental presence of cyclic dimethyl siloxanes in the Scandinavia region detected dodecamethylcyclohexasiloxane in air sampled near urban areas, landfills, sewage treatment plants, and other point sources. The concentration of dodecamethylcyclohexasiloxane ranged from 0.5-2.1 ug/cu m(1).

Indoor dust samples (100 samples total) collected from various sites in China in 2009 contained median dodecamethylcyclohexasiloxane concentrations of 11.0-20.5 ng/g(1).|Dodecamethylcyclohexasiloxane concentrations in a variety of consumer products(1).[Table#7399]|The residues of additives and other chemicals in 23 kinds of silicone rubber products for food contact use, including nipples, packing and spatulas, were investigated by GC-MS. All of the samples contained 15 to 20 peaks of polydimethylcyclosiloxanes. Dodecamethylcyclohexasiloxane (D6) to tetratriacomethylcycloheptadecasiloxane (D17) were confirmed, and other larger siloxanes up to pentacontamethylcyclopentacosasiloxane (D25) were estimated. A rough estimate of the total cyclosiloxane content was 3,310-14,690 ug/g.

IDENTIFICATION AND USE: Typically including dodecamethylcyclohexasiloxane (D6) with a general formula of (-Si(CH3)2O-)x in a cyclic configuration, where x is generally less than 8, and more commonly x is 3-7. This formulation is commonly used in cosmetics. Other uses include electronics, furniture, health-care products, cookware, and medical devices. It is also used as surface treatments, paint, lacquers, and varnishes. HUMAN EXPOSURE AND TOXICITY: No data. ANIMAL STUDIES: D6 was not toxic in rats when given as a single dose orally, or dermally (2000 mg/kg). Eye instillation of the test substance induced conjunctival irritation (redness) in rabbits, and all reactions had cleared within 24 hours. The 4-hour dermal application of D6 did not induce irritation, corrosion, or staining in rabbits. In rats doses of 1000 or 1500 mg/kg body weight per day for 28 days did not produced signs of local or systemic toxicity. In reproductive/developmental toxicity screening tests in rats high dose animals demonstrated microscopic findings in liver (fatty change in females only), lung, and thyroid. An increase in the number of sperm-positive, non-gravid females was reported for the high dose group. In males, prothrombin time was prolonged at the 2 highest dose levels; however, there were no clinical indications of clotting abnormalities. Absolute and/or relative organ weight increases were observed in the liver and kidneys (both sexes) and in the adrenal glands (females only). Mutagenicity of D6 in the Salmonella typhimurium reverse mutation assay was evaluated using S. typhimurium strains: TA 98, TA100, TA1535, and TA1537. The mutagenicity of D6 was also evaluated in the Escherichia coli reverse mutation assay using E. coli strain WP2 uvrA. D6 was not mutagenic in the S. typhimurium reverse mutation assay or in the E. coli reverse mutation assay with or without activation.

LD50 Rat oral >2000 mg/kg|LD50 Rat dermal >2000 mg/kg

Dodecamethylcyclohexasiloxane's production and use as an intermediate in the manufacture of siloxane polymers, as an ingredient in cosmetics and personal care products, and as a defoamer in the processing of certain food products and in other industries(1) may result in its release to the environment through various waste streams(SRC). Similar to D5 (decamethylcyclopentasiloxane)(2), its use as 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). Consumer and professional uses of personal care products containing dodecamethylcyclohexasiloxane result in 100% loss of the substance to the environment(3); the majority of this loss (90%) is to air and the remainder is lost to waste water(3).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 870,000(SRC), determined from a structure estimation method(2), indicates that dodecamethylcyclohexasiloxane is expected to be immobile in soil(SRC). Volatilization of dodecamethylcyclohexasiloxane from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 25.0 atm-cu m/mole(3). However, adsorption to soil is expected to attenuate volatilization(SRC). Dodecamethylcyclohexasiloxane is a volatile methylsiloxane that favors partitioning into the atmosphere(4); therefore, dodecamethylcyclohexasiloxane is expected to volatilize from dry soil surfaces(SRC) even with a vapor pressure of 0.0169 mm Hg(5). Evaporation of dodecamethylcyclohexasiloxane was measured in soil studies and found to occur with rates varying with moisture content, soil type and relative humidity(6). Volatilization from soil may be the major loss process under certain moist conditions(7). Dimethyl siloxanes, in general, are highly resistant to biodegradation(8). Biodegradation of dodecamethylcyclohexasiloxane of 4.47% using a 28 day ready-biodegradability test(7) suggests that biodegradation is not an important environmental fate process in soil(SRC). The abiotic degradation of volatile methylsiloxanes in soil (such as dodecamethylcyclohexasiloxane) is thought to occur via mechanisms such as hydrolysis reactions catalyzed by the surface activity of soil clays(6). Based on degradation studies in tropical (Hawaiian) and temperate soils(6), abiotic soil half-lives of 1.8-3.0 days and 158-202 days have been estimated for these two soil types, respectively(9).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 870,000(SRC), determined from a structure estimation method(2), indicates that dodecamethylcyclohexasiloxane 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 25.0 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 6.2 hours and 8.4 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 >1 year if adsorption is considered(5). According to a classification scheme(6), a BCF range of 1,160 to 1,660 measured in fathead minnows (Pimephales promelas)(7), suggests the potential for bioconcentration in aquatic organisms is very high(SRC). Dimethyl siloxanes, in general, are highly resistant to biodegradation(8). Biodegradation of 4.47% using a 28 day ready-biodegradability test(9) suggests that biodegradation is not an important environmental fate process in water(SRC). Based on measured aqueous hydrolysis rate data at higher temperatures, the hydrolysis half lives of dodecamethylcyclohexasiloxane at 25 °C were extrapolated to be 42 hours at pH4, 401 days at pH 7 and 125 hours at pH 9(9). However, strong adsorption to sediment may limit the rate of hydrolysis in natural waters(10).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), dodecamethylcyclohexasiloxane, which has a vapor pressure 0.0169 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase dodecamethylcyclohexasiloxane 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 9 days(SRC), calculated from its rate constant of 1.8X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Methylcyclosiloxanes do not absorb UV light(4) and, therefore, dodecamethylcyclohexasiloxane is not expected to be susceptible to direct photolysis by sunlight(SRC). Volatile methylsiloxanes, which are primarily released or partitioned to the atmosphere(4), 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(4).

The rate constant for the vapor-phase reaction of dodecamethylcyclohexasiloxane with photochemically-produced hydroxyl radicals has been estimated as 1.8X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 9 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Methylcyclosiloxanes do not absorb UV light(2) and, therefore, dodecamethylcyclohexasiloxane is not expected to be susceptible to direct photolysis by sunlight(SRC). Based on measured aqueous hydrolysis rate data at higher temperatures, the hydrolysis half lives of dodecamethylcyclohexasiloxane at 25 °C were extrapolated to be 42 hours at pH 4, 401 days at pH 7 and 125 hours at pH 9(3).|The degradation of volatile methylsiloxanes in soil (such as dodecamethylcylohexasiloxane) is thought to occur via abiotic mechanisms such as hydrolysis reactions catalyzed by the surface activity of soil clays(1). 14C-labeled dodecamethylcylohexasiloxane was added to soil that was pre-conditioned at a desired relative humidity, and incubated for 0-21 days using closed and open systems(1); the compound was found to hydrolyze readily in Hawaiian Wahiawa soil at 22 °C and 32% relative humidity in the dark (half-life of 1.38 days), to form degradation intermediates (oligomeric diols)(1). Polydimethylsiloxane fluids in intimate contact with many soils undergo siloxane redistribution and hydrolysis, resulting in formation of low molecular weight cyclic and linear oligomers(2). Low molecular weight hydroxy-functional hydrolysis products are water soluble and the cyclics and trimethylsiloxy end blocked oligomers are volatile, thus providing materials which can partition from the soil to the water and atmospheric environmental compartments(2).

A steady-state BCF of 1,160 and a kinetic BCF of 1,660 were measured for dodecamethylcyclohexasiloxane using fathead minnows (Pimephales promelas) which were exposed to a concentration of 0.41-4.4 ug/L of dodecamethylcyclohexasiloxane for approximately 49 days(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is very high(SRC).|Many chemicals in commerce are classified as 'super-hydrophobic', having log octanol-water partition coefficients (log KOW) approaching or exceeding 7. Examples include long chain alkanes, halogenated aromatics and cyclic volatile methylsiloxanes (cVMS). We show that super-hydrophobic chemicals present unique assessment challenges because of their sparing solubility in water and difficulties in empirical determinations of Bioconcentration Factors (BCFs) and aquatic toxicity. Using cVMS as an example, BCFs are considerably lower than expected due to biotransformation. Reviewed aquatic toxicity test data for cVMS in a range of aquatic organisms show little or no toxic effects up to solubility limits in water and sediment. Explanations for this apparent lack of toxicity of cVMS, and by extension to other super-hydrophobic chemicals, are explored using a conventional one-compartment uptake model to simulate bioconcentration and toxicity tests using an assumed baseline narcotic Critical Body Residue (CBR) and a range of organism sizes. Because of the low aqueous concentrations, equilibration times are very long and BCFs are sensitive to even very slow rates of biotransformation. Most organisms fail to achieve the assumed CBR during feasible test durations even at the solubility limit. Regulatory evaluation of super-hydrophobic substances requires specially designed test protocols addressing biotransformation and dietary uptake. /Cyclic volatile methylsiloxanes/

Using a structure estimation method based on molecular connectivity indices(1), the Koc of dodecamethylcyclohexasiloxane can be estimated to be 870,000(SRC). According to a classification scheme(2), this estimated Koc value suggests that dodecamethylcyclohexasiloxane is expected to be immobile in soil.

The Henry's Law constant for dodecamethylcyclohexasiloxane is 25.0 atm-cu m/mole(1). This Henry's Law constant indicates that dodecamethylcyclohexasiloxane is expected to volatilize rapidly from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is estimated as 6.2 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is estimated as 8.4 days(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 >1 year if adsorption is considered(3). The Henry's Law constant for dodecamethylcyclohexasiloxane indicates that volatilization from moist soil surfaces is expected(SRC). Dodecamethylcyclohexasiloxane is a volatile methylsiloxane that favors partitioning into the atmosphere(4); therefore, dodecamethylcyclohexasiloxane is expected to volatilize from dry soil surfaces(SRC) even with a vapor pressure of 0.0169 mm Hg(5). Evaporation of dodecamethylcyclohexasiloxane was measured in soil studies and found to occur with rates varying with moisture content, soil type and relative humidity(6). Volatilization from soil may be the major loss process under certain moist conditions(7).

GROUNDWATER: Dodecamethylcyclohexasiloxane was detected in ground water samples from an industrialized area near Milan, Italy. The samples were collected at Limbiate, Senago, and Bollate during four sampling campaigns (Nov 1995, Jan 1996, Oct 1996, and Nov 1996) following active carbon purifying treatment. The samples were analyzed by GC-MS and showed a low relative abundance of dodecamethylcyclohexasiloxane with respect to other contaminants detected(1).|DRINKING WATER: Dodecamethylcyclohexasiloxane was identified in drinking water concentrates from New Orleans, LA and Seattle, WA(1).|SURFACE WATER: A surface water sample collected from an industrialized area in Stenungsund, Sweden during a national sampling program contained 0.04 ug/L of dodecamethylcyclohexasiloxane(1). In 2006, the Canadian Centre for Inland Waters reported dodecamethylcyclohexasiloxane at a concentration of <17 ng/g (detection limit) at an undisclosed location in the Great Lakes region(2).|A study focused on determining environmental presence of cyclic dimethyl siloxanes in the Scandinavia region detected dodecamethylcyclohexasiloxane in landfill ground water, seawater, and rivers at a concentration range of <0.03-3.8 ug/L(1).

ENVIRONMENTAL: In a national sampling survey in Sweden one or more cyclic siloxanes including dodecamethylcyclohexasiloxane(D6), decamethylcyclopentasiloxane(D5), and octamethylcyclotetrasiloxane(D4) were detected in 11 out of 49 human breast milk samples. The maximum concentration of dodecamethylcyclohexasiloxane was 4.8 ug/L. Linear siloxanes were detected in 6 of the samples at much lower levels(1).

According to the 2012 TSCA Inventory Update Reporting data, 4 reporting facilities estimate the number of persons reasonably likely to be exposed during the manufacturing, processing, or use of dodecamethylcyclohexasiloxane(540-97-6) may be as low as <10 workers up to the range of 10-24 workers per plant; the data may be greatly underestimated due to confidential business information (CBI) or unknown values(1).|Occupational exposure to dodecamethylcyclohexasiloxane may occur through inhalation and dermal contact with this compound at workplaces where dodecamethylcyclohexasiloxane is produced or used. Monitoring data indicate that the general population may be exposed to dodecamethylcyclohexasiloxane via inhalation of ambient air, inhalation of air near cosmetic or personal care products containing dodecamethylcyclohexasiloxane, ingestion of fish, and dermal contact with this consumer products containing dodecamethylcyclohexasiloxane. (SRC)|Silicones applied to electrical relay contacts as a lubricant, photocopiers as a heat transfer fluid, and other electrical devices can lead to volatilization at telephone switching office sites(1). Polymeric films derived from airborne organic silicones have been identified to cause relay failures and as a consequence have resultedin indoor air monitoring at telephone switching offices and data centers(2). Air samples collected at a telephone switching office in Neenah, WI detected dodecamethylcyclohexasiloxane via GC-MS(coeluted with Texanol-3) at a concentration of 5.8 ug/cu m in a break room (Dec 1987) and 3.9 ug/cu m in the same break room (Feb 1998)(3). Outdoor air samples taken did not detect dodecamethylcyclohexasiloxane(3). During the installation of a DMS 100 switch at the Neenah, WI site, dodecamethylcyclohexasiloxane was detected in air samples in May 1988 at a concentration of 12.1 ug/cu m on the first floor at 3.2 ug/cu m on the second floor, at 8.6 ug/cu m in the break room, and none detected outdoors(3). In Jul 1988 detection was limited to the second floor and break room at 3.6 ug/cu m and 5.4 ug/cu m, respectively. Indoor air samples collected at several telephone office buildings allowed calculation of a diffusion coefficient and uptake rate for dodecamethylcyclohexasiloxane which are 0.0348 cm sq/sec and 14.8 cu cm/min, respectively(2).|The average daily dodecamethylcyclohexasiloxane exposures for US women aged 19-65 years in ug/day is estimated to be 333 (shampoo); 1,310 (hair conditioners); 0 (body washes); 1.1 body lotions); 6,100 (face creams); 0.098 (lipsticks); 14,400 (liquid foundations), 22,200(total daily exposure)(1).

Surrounding breast tissues of women with silicone gel augmented breasts were sampled and analyzed by GC-MS. The tissues contained several cyclic siloxanes including dodecamethylcyclohexasiloxane at the following levels measured in ng/g; fat tissue (woman A = 780, woman B = 146); capsule tissue (woman B = 101.6, woman C = 251.1); muscle tissue (woman B = 25.08); fibrin layer (woman C = 385); breast tissue (none detected)(1). A study aimed at determining chemical composition and diffusion of low molecular weigh(LM) silicone gels from breast implants, detected dodecamethylcyclohexasiloxane by GC-MS and GC-AED. LM silicone breast implants dissolved in ethyl acetate showed approximately 1-2% of the total weight of the implant to be composed of linear and cyclic siloxanes including dodecamethylcyclohexasiloxane. Greatest diffusion rate of LM silicones into lipid-rich media was measured at 10 mg/day per 250 g implant at 37 °C(2).|In a national sampling survey in Sweden one or more cyclic siloxanes including dodecamethylcyclohexasiloxane (D6), decamethylcyclopentasiloxane (D5), and octamethylcyclotetrasiloxane (D4) were detected in 11 out of 49 human breast milk samples. The maximum concentration of dodecamethylcyclohexasiloxane was 4.8 ug/L. Linear siloxanes were detected in 6 of the samples at much lower levels(1).

/Researchers/ evaluated the percutaneous absorption of neat D6 radiolabeled with (14)C following application to human skin in vitro. The test substance was applied under semiocclusive conditions in a Teflon flowthrough diffusion cell system. Human epidermis was prepared from abdominal skin (6 donors). The epidermis with the top layer of dermis was separated from the rest of the skin by dermatoming, and the skin samples were mounted in replicate. Skin samples from 3 donors passed the barrier integrity test. A physiological receptor fluid was pumped beneath the skin samples. Skin samples from each of the 6 donors were dosed with neat (14)C-cylohexasiloxane (14C-D6) at a target dose of 6 mg/sq cm during the 24-hour-exposure period. At the conclusion of the assay, the majority of the applied dose was located on the skin surface (46.407% of applied dose) or volatilized from the dosing site and collected in charcoal traps (40.057% of applied dose). Practically no (14)C-D6 penetrated through the skin and into the receptor fluid. The percentage of applied neat (14)C-D6 recovered from all samples that were analyzed was 89.542% +/- 4.154%, which included 3.075% of the applied neat (14)C-D6 (SE of the mean = 0.852% of the applied dose) that was found in the skin. The results of an additional experiment indicated that, after the skin was washed at 24 hours, the portion of (14)C-D6 observed in the skin did not penetrate through the skin, but continued to evaporate. Thus, it was concluded that, under the conditions of this assay, D6 was not percutaneously absorbed.|/Researchers/ evaluated the disposition of (14)C-D6 using 10 groups of Fischer 344 rats (CDF(F-344)/ CrlBR strain). The animals were 8 to 10 weeks old and body weight ranges were 163 to 219 g (males) and 133 to 155 g (females). A single oral dose of (14)C-D6 (in corn oil, 1000 mg/kg body weight) was administered to a group of 4 males and 4 females; metabolism cages were used for the collection of urine, feces, and expired air. The animals were killed at 168 hours postdosing, and selected tissues and remaining carcasses collected and analyzed for radioactivity. Expired volatiles and feces were also analyzed for parent D6 concentration. A separate group of rats (6 males and 6 females), cannulated via jugular vein, was used to determine radioactivity and parent D6 concentration in the blood at 15 minutes and at 1, 6, 12, 18, 24, 48, 72, 96, 120, 144, and 168 hours postdosing. Wholebody autoradiography (WBA) was used for qualitative in vivo assessment of tissue distribution of radioactivity in male and female rats after single oral administration of D6 (in corn oil). Animals in the WBA groups were killed at 1, 4, 24, 48, 96, and 168 hours postdosing. In males and females, the majority of the administered dose was excreted in the feces. Based on the recovered radioactivity (urine, expired volatiles, expired CO2, tissues, and carcass), the absorption of D6 was 11.88% (males) and 11.83% (females) of the administered dose. For most of the recovered radioactivity, a similar pattern of distribution of the radioactivity was noted in males and females. However, considerable variability in the levels of radioactivity in expired volatiles was reported, which may have been due to off gassing from the fecal pellets that were not collected, as intended, but remained on the inside of the cage. The authors noted that this phenomenon could potentially produce some false high values for expired volatiles and absorption due to partitioning from the fecal matter into the air. All of the radioactivity in the expired volatiles was attributed to parent D6. Metabolic profile evaluation of the urine and feces indicated that all of the radioactivity in the urine consisted of polar metabolites, whereas, in the feces, the majority was parent D6, with a trace nonpolar metabolite. Whole body autoradiography data supported mass balance data showing that the majority of administered D6 in corn oil stayed in the gastrointestinal (GI) tract and was excreted in the feces within 48 hours. Low levels of radioactivity were detected in organs and tissues, such as the liver, fat tissue, and bone marrow, indicating some absorption of D6. Statistical analysis of blood curves indicated the presence of small amounts of metabolites in the blood, based on the difference between radioactivity and parent AUCs (AUCmetabolites = AUCradioactivity AUCparent).|Silicone [poly(dimethylsiloxane)] gel used in breast implants has been known to migrate through intact silicone elastomer shells, resulting in the clinically observable "gel bleed" on the implant surface. Although silicon concentrations in capsular tissues of women with silicone prostheses have been measured with element-specific silicon analyses, no silicone-specific investigation of these tissues has been performed as yet. A combination of element-specific inductively coupled plasma high-resolution isotope dilution mass spectrometry (ICP-HR-IDMS) and species-specific gas chromatography coupled mass spectrometry (GC-MS) was used to analyze silicon, platinum, and siloxanes in prosthesis capsule, muscle, and fat tissues of women (n=3) who had silicone gel-filled breast implants and in breast tissue of non-augmented women (n=3) as controls. In all tissues of augmented women, siloxanes, in particular octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) were identified. Depending on the siloxane species and type of tissue analyzed, siloxane levels in the range of about 10-1,400 ng/g were detected; total silicon was found in all tissue samples in the range of about 8,900-85,000 ng/g. Higher platinum levels ranging from 25-90 ng/g were detected in fibrin layer and fat tissue of two patients with prostheses. No siloxanes were detected in control breast tissue samples. This investigation of human tissues by a combination of element-specific and species-specific analytical techniques clearly demonstrates for the first time that platinum and siloxanes leak from prostheses and accumulate in their surrounding tissues.|To examine the distribution of low molecular weight silicones in body organs, separate groups of female CD-1 mice were injected with either breast implant distillate composed primarily of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and tetradecamethylcycloheptasiloxane or a polydimethylsiloxane oil containing low molecular weight linear siloxanes. Mice were injected subcutaneously in the suprascapular area and killed at different times. Levels of individual low molecular weight silicones were measured in 10 different organs (brain, heart, kidney, liver, lung, mesenteric lymph nodes, ovaries, spleen, skeletal muscle, and uterus). In mice treated with the cyclosiloxane mixture and killed at 3, 6, or 9 weeks, highest levels of cyclosiloxanes were found in the mesenteric lymph nodes, ovaries, and uterus, but all organs examined contained cyclosiloxanes. In a cohort killed at 1 year, most organs contained measurable cyclosiloxanes with highest levels in mesenteric lymph nodes, abdominal fat, and ovaries. Of the individual cyclosiloxanes measured, selective retention of decamethylcyclopentasiloxane and dodecamethylcyclohexasiloxane relative to octamethylcyclotetrasiloxane was seen in all organs at all time points studied. Organs from animals receiving the linear siloxane mixture were harvested at 9, 12, and 15 weeks. ... Maximum levels in the brain, lungs, and mesenteric lymph nodes /were found/, but all other organs contained measurable levels. These data are, to the best of our knowledge, the first demonstration that after a single subcutaneous injection silicones are widely distributed throughout the body and can persist over an extended period.|The disposition of (14)C-dodecamethylcyclohexasiloxane (D6) was evaluated in male and female F344 rats following a single oral administration of 1000 mg of (14)C-D6 in corn oil/kg of body weight. Animals (N=4/sex) were housed in glass metabolism cages for collection of excreta and expired volatiles. At 168 hr post-dose, animals were sacrificed and selected tissues and remaining carcasses were collected. All samples were analyzed for radioactivity content. Feces and expired volatiles were also analyzed for parent D6 concentration. A separate group of animals, cannulated via the jugular vein, (N=6/sex) was used to determine radioactivity and parent D6 concentration in blood at predetermined time points. Whole-body autoradiography (WBA) was used for qualitative in vivo assessment of tissue distribution of radioactivity. The majority of administered radioactivity (>80%), regardless of sex, was eliminated in the feces. Total absorption (radioactivity recovered in urine, expired volatiles, expired CO2, tissues and carcass) in males and females was 11.88% and 11.83%, respectively. Both sexes showed similar patterns of disposition (Urine: 0.38% and 0.32%; Expired volatiles: 11.20% and 11.21%; Expired CO2: 0.13% and 0.09%; Tissues: 0.03% and 0.04%; Carcass: 0.14% and 0.17% for males and females, respectively). The entire radioactivity in the expired volatiles was attributed to parent D6. Metabolic profile evaluation showed that the entire radioactivity in the urine consisted of polar metabolites, whereas in the feces the majority was parent D6 with a trace of nonpolar metabolite. The WBA data also showed that the majority of D6 remained in the GI tract and was excreted in feces within 48 hr. Low levels of radioactivity were systemically available and distributed to organs and tissues such as liver, brown fat and bone marrow. Statistical analysis of the blood curves indicated the presence of small levels of metabolites in the blood (approximately 117 ug equivalent D6*hr/g of blood). In summary, approximately 12% of (14)C-D6 delivered in corn oil appeared to be absorbed after a single oral administration to F344 rats.

218.78 Days

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/|/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/|/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

dodecamethylcyclohexasiloxane

Typically including dodecamethylcyclohexasiloxane (D6) with a general formula of (-Si(CH3)2O-)x in a cyclic configuration, where x is generally less than 8, and more commonly x is 3-7. This formulation is commonly used in cosmetics.

All other basic inorganic chemical manufacturing|Cyclohexasiloxane, 2,2,4,4,6,6,8,8,10,10,12,12-dodecamethyl-: ACTIVE|Cyclomethicone, is a common name for a mixture of cyclic dimethyl siloxanes|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.

Cosmetics -> Emollient; Hair conditioning; Solvent