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Colloidal silver
Colloidal silver refers to microscopic particles of silver that are held in a liquid suspension. A colloid is technically defined as particles which remain suspended without forming an ionic, or dissolved solution. The broader commercial definition of colloidal silver includes products that contain various concentrations of ionic silver, silver colloids, ionic silver compounds or silver proteins in purified water. Colloidal silver with concentrations of 30 parts per million (ppm) or less are typically (but not always) manufactured using an electrolyte process, whereas colloidal silver with higher concentrations of 50 ppm or more are usually (but not always) either silver compounds such as silver chloride and silver iodide or are solutions that have been bound with a protein to disperse the particles. Additional recommended knowledge
History and ApplicationsPrior to 1938, colloidal silver was widely used by physicians as a mainstream antibiotic.[1] It was produced by pharmaceutical companies under various names, including Protargol. But the electro-colloidal production process was costly and the pharmaceutical industry developed fast-acting, less-expensive sulfa drugs and penicillin. Silver nitrate solutions were introduced by Credé in 1880 to protect newborn infants' eyes from infection.[2], but have largely been replaced by antibiotic ointments since 1978[3][4]. This silver nitrate is a solution of a silver salt, not a suspension of colloidal silver. Silver-based cremes have been used in burn centers for more than 100 years.[5] Colloidal silver can be used to keep drinkable water potable over a long period.[citation needed] Concentrations of colloidal silver at 5 parts per million or higher have been found to kill numerous infectious bacteria.[6] Colloidal silver has been approved by the EPA as a disinfectant for hospitals and medical centers.[7] Method of ActionColloidal silver might kill bacteria by inhibiting the expression of enzymes and other proteins essential to ATP production. [8] It can be expected to have similar effects on human enzymes. ToxicitiesArgyriaLong-term intake of silver products may result in a condition known as argyria, one symptom of which is a blue or gray discoloration of the skin.[9] It occurs when sunlight interacts with silver deposited in the skin, in the same way that silver particles in photographic film darken when exposed to sunlight. It can occur both via ingestion of silver, or through topical application of silver to the skin.[citation needed] While generally considered permanent[10], some have claimed to have reversed it.[11] Death from argyria has been reported from as little as four months use of oral colloidal silver[12] , and cases of kidney damage, stomach distress, and headaches have been reported, as well as cases of brain and nerve damage.[13][14] [15][16]An FDA “Talk Paper” references silver ingredients and silver salts that includes silver proteins, silver chloride and silver iodide. They claim that the use of these “gelatinous” silver solutions have resulted in cases of argyria.[17] Advocates claim that almost all known cases of argyria resulted from use of highly concentrated silver compounds such as silver oxide, silver nitrate or silver chloride and not the electrolyte-manufactured solutions, which contain only ionic and colloidal silver and typically comprise silver concentrations of 30 ppm or less. Advocates assert that, under careful use of properly produced colloidal silver, argyria is virtually impossible,[18] though these claims are anecdotal and have not been confirmed by scientific study. Advocates also claim that very few if any current cases are known to exist. They view the entire controversy as an orchestrated scare tactic by special interests who they say deliberately exaggerate and mislead people away from colloidal silver products. However, verified cases of argyria continue to be reported and proven, sometimes making the television news programs.[19][20][21]. Many scientific articles report cases of argyria after ingestion of colloidal silver [22] [23] [24] [25] [26] [27]. Government reactionsThe U.S. Food and Drug Administration (FDA) banned over-the-counter sales in the U.S. of any product claiming to have therapeutic value, health benefits, or making any medical claims, unless it has undergone the rigorous safety and efficacy testing required of pharmaceuticals. As such testing has not been conducted with colloidal silver, the product now has the status of a dietary supplement in the US (dietary supplements cannot claim to cure diseases, only that they "support healthy functioning").[28] The FDA has issued warnings to Internet sites selling or promoting colloidal silver as an antibiotic or for other medical purposes.[29] If no medical benefits are claimed, colloidal silver is sold as a supplement, and as long as the products comply with all other FDA regulations, its sale is considered legal.[30] In 2002, the Australian Therapeutic Goods Administration made a similar ruling.[31] Differing preparationsThe term, "colloidal silver", has been used inaccurately by some to advertise products which are solutions of either silver salts, or proteins bound with silver[citation needed]. This misrepresentation contributes to over-all confusion about the term "colloidal silver". In order for a mixture to be a true silver colloid, the silver atoms must be tiny metallic particles suspended in a liquid. Confusion around colloidal silver is increased by the fact that there is more than one manufacturing process, and that these lead to a number of significantly different products that have differing properties[citation needed], all of which go by the name "colloidal silver". Preparations called 'colloidal silver' include:
References
See alsoCategories: Silver | Nanomaterials |
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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Colloidal_silver". A list of authors is available in Wikipedia. |