This article was taken from the October issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content bysubscribing online
Each month Wired’s chemist Dr John Emsley, author of nine books and 110 research papers, deconstructs an everyday product. This month: Voltarol Emulgel P
Soothe aching muscles with a preservative for Tudor shipwrecks and a kitsch 70s light source
Ingredients
> Diclofenac diethylammonium
> Diethylamine
> Carbomer
> Macrogol cetostearyl ether
> Cocoyl caprylocaprate
> Isopropyl alcohol
> Liquid paraffin
> Perfume
> Propylene glycol
> Purified water
Propylene glycol (aka 1,2-propanediol, chemical formula CH3CH(OH)CH2OH)This solvent keeps the other ingredients suspended in the gel. Derived from natural gas, propylene glycol is used as antifreeze.
Cocoyl caprylocaprateThis consists of saturated fatty acids with eight or ten carbon atoms in their chain, linked to fatty alcohols with 12 to 18 carbon atoms. Useful base ingredient.
Diclofenac diethylammoniumAn NSAID (nonsteroid antiinflammatory drug), diclofenac blocks the cyclo-oxygenases enzymes (aka COX-2) that produce the prostaglandins that trigger pain, but does not block the COX-1 enzymes that protect the stomach and intestine lining.
Macrogol cetostearyl etherA polyethylene glycol with fatty alcohols attached. It makes an ideal base chemical for ointment because it blends well. Polyethylene glycol is used to preserve wooden shipwrecks that have been raised and exposed to air, such as Henry VIII’s Mary Rose.
Diethylamine (chemical formula (CH3CH2)2NH)Made from alcohol and ammonia, this has a urine-like smell and is used in the manufacture of rubber, dyes, pesticides and pharmaceuticals. Here it ensures that all of the diclofenac remains non-acidic. In conjunction with salicylic acid, it is the active ingredient in older treatments for rheumatism, such as Deep Heat.
Liquid paraffinA mix of hydrocarbons distilled from crude oil, it’s a collection of similar molecules with 15 to 40 carbon atoms in the chain. It is used in hydraulic fluids, wood preservatives, baby oils, cosmetics and lava lamps. Although previously taken to relieve constipation, liquid paraffin has been discontinued because it can interfere with the absorption of oil-soluble vitamins, such as A, D and E.
CarbomerAdded as a thickening agent and emulsifier to help the other ingredients to blend smoothly, this is a polymer of acrylic acid cross-linked with sugar molecules. Acrylic polymers are the basis of plastics such as Perspex, and are used in paints.
Isopropyl alcohol (aka isopropanol, chemical formula (CH3)2CHOH)A solvent for oily ingredients such as cocoyl caprylocaprate (see above, left), it is used industrially in its own right as a solvent, as well as being found in windscreen washers and deicing sprays.
This article was originally published by WIRED UK
