Polydimethylsiloxane
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| General | |||||||||
| Surname | Polydimethylsiloxane | ||||||||
| other names | |||||||||
| CAS number | 63148-62-9 | ||||||||
| Monomer | Dimethylsiloxane | ||||||||
| Molecular formula of the repeating unit | C 2 H 6 OSi | ||||||||
| Molar mass of the repeating unit | 74.15 g mol −1 | ||||||||
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| DrugBank | DB11074 | ||||||||
| Drug information | |||||||||
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| properties | |||||||||
| density |
0.98 g cm −3 |
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| Melting point |
no melting point; Glass transition at −125 ° C |
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| solubility |
practically insoluble in water |
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| safety instructions | |||||||||
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| As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . | |||||||||
Polydimethylsiloxane ( PDMS ) is a silicon- based polymer and, as the simplest silicone oil, is one of the siloxanes . It is colorless, transparent, and is considered non-toxic and chemically inert . Based on the English name Dimethicone , it is used as a medicinal substance under the name Dimeticon ( INN ) against gas accumulation in the gastrointestinal tract and as a defoamer for surfactant poisoning. Other uses include as a pediculocide (i.e., against head lice ), as a lubricant for the majority of condoms sold, and for cosmetic products.
properties
The boiling point is around 200 ° C (for low-molecular types, high-molecular ones decompose before evaporation at> 200 ° C) and the vapor pressure is 6.66 h Pa at 20 ° C.
Pharmaceutical grades (Dimeticon (Ph. Eur.)) Are clear, colorless liquids whose kinematic viscosities are nominally 20 to 1300 mm 2 s −1 , depending on the degree of polymerization (approx. 20 to 400) . They are practically insoluble in water, practically insoluble to very sparingly soluble in anhydrous ethanol , miscible with ethyl acetate , with methyl ethyl ketone and with toluene .
Medical use
Defoamer
Dimethicone, also known as polydimethylsiloxane (PDMS) is used as entblähendes, antiflatulentes means for gas retention in the gastrointestinal tract (bloating, tympanites , meteorism , roemheld syndrome ), interfering to reduce accumulations of gas in X-ray , endoscopy - and ultrasound examinations as well as defoamers used for poisoning with surfactants . Enriched with solid SiO 2 particles, it is called simeticon .
Dimeticon is a long-chain organic silicon compound that - purely physically - lowers the surface tension of trapped gas bubbles in the gastrointestinal tract and thus dissolves them. The gases can be absorbed in the intestine or go off naturally. There is no absorption or chemical reaction of the agent in the body; it is inert and is excreted unchanged after the intestinal transit.
Side effects have not yet been observed.
Pediculocide
According to randomized clinical studies, a Dimeticon solution is also effective against head lice .
Two pediculocidal modes of action are discussed:
- Asphyxiation by penetration of the dimeticone into the trachea of the lice and
- Cardiac arrest, because the softening of the chitin armor prevents the heart from contracting because it is attached to the chitin armor.
Side effects have not yet been observed. However, after using 4% dimethicone 96% cyclometicone combination agents, the hair is easily flammable for a short time, which in individual cases can lead to severe burns.
Use as a food additive
Polydimethylsiloxane is approved as a food additive in the anti-foam group (E 900). It is used in the food industry in the production of jams, jams, canned fruit and vegetables and (deep-frying) fats.
Technical application
In addition to medical applications, PDMS plays an important role in technology as:
- Lubricant , e.g. B. with condoms for sliding coating
- Thermal oil
- Adsorbents in analytical chemistry , e.g. B. in solid phase micro-extraction or stir bar sorptive extraction
- Stamp in polymer electronics
- Damping medium
- Various applications in microfluidics: lab-on-a-chip, fluid channels, bioreactors, etc.
- Addition to quartz sand for the production of kinetic sand, a product of the toy industry that can be worked like wet sand
Trade names
- substance
Baysilon, KORASILON
- Medicines and medical devices
- Monopreparations
Ceolat (D), Ilio-Funktion (D), EtoPril, Hedrin, Itax, Jacutin Pedicul Fluid, Nyda, Paramitex
Hevert enzyme comp. (D), Pankreoflat (D)
Individual evidence
- ↑ Entry on E 900: Dimethyl polysiloxane in the European database for food additives, accessed on August 11, 2020.
- ↑ Entry on DIMETHICONE in the CosIng database of the EU Commission, accessed on August 11, 2020.
- ↑ a b c d e Entry on polydimethylsiloxane in the GESTIS substance database of the IFA , accessed on July 30, 2017(JavaScript required) .
- ^ Thomas G. Mezger: Das Rheologie-Handbuch . FARBE UND LACK, 2016, ISBN 978-3-86630-633-2 , p. 211 ( limited preview in Google Book search).
- ↑ Tiernan Coyle, Naveed Anwar: A novel approach to condom lubricant analysis: In-situ analysis of swabs by FT-Raman Spectroscopy and its effects on DNA analysis. In: Science & Justice. 49, 2009, pp. 32-40, doi : 10.1016 / j.scijus.2008.04.003 .
- ^ RD Blackledge, M. Vincenti: Identification of polydimethylsiloxane lubricant traces from latex condoms in cases of sexual assault. In: Journal - Forensic Science Society. Volume 34, Number 4, 1994 Oct-Dec, pp. 245-256, PMID 7844517 .
- ↑ European Pharmacopoeia 9.0, pp. 2281 f., Dimeticone .
- ↑ Burgess, IF et al. (2005): Treatment of head louse infestation with 4% dimeticone lotion: randomized controlled equivalence trial. In: BMJ Volume 330, page 1423. doi : 10.1136 / bmj.38497.506481.8F , PMID 15951310 .
- ↑ Burgess IF et al. (2007): Randomized, controlled, assessor blind trial comparing 4% dimeticone lotion with 0.5% malathion liquid for head louse infestation. In: PLoS ONE. Volume 2, page 1127. PMID 17987114 , PMC 2043492 (free full text).
- ↑ Feldmeier H. (2006): Pediculosis capitis, The most important parasitosis of childhood. In: Pediatric and Adolescent Medicine. Number 4, pages 249-259. PDF .
- ↑ Dimeticon preparations against head lice infestation . In: DAZ No. 6 / February 2009.
- ↑ Federal Institute for Drugs and Medical Devices: Flammability risk of dimethicone and cyclomethicone containing anti-lice products. (BfArM press release of January 12, 2009).
- ↑ Entry on dimethylpolysiloxane at Zusatzstoffe-online.de
