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Betadine is a stable chemical complex of polyvinylpyrrolidone (povidone, PVP) and elemental iodine. It contains from 9.0% to 12.0% available iodine, calculated on a dry basis.〔(United States Pharmacopeia ) 〕 This unique complex was discovered in 1955 at the Industrial Toxicology Laboratories in Philadelphia by H. A. Shelanski and M. V. Shelanski.〔U.S.patent 2,739,922〕 They carried out tests ''in vitro'' to demonstrate anti-bacterial activity, and found that the complex was less toxic in mice than tincture of iodine. Human clinical trials showed the product to be superior to other iodine formulations. Betadine was immediately marketed, and has since become the universally preferred iodine antiseptic. Betadine is only sold for the purpose of healing wounds, and not as an oral sore throat gargle, as widely thought. The Betadine gargle is an unregistered company and legal issues are pending in the court against it.〔 ==Medical uses== Povidone-iodine is a broad spectrum antiseptic for topical application in the treatment and prevention of infection in wounds. May be used in first aid for minor cuts, grazes, burns, abrasions and blisters. Following the discovery of iodine by Bernard Courtois in 1811, it has been broadly used for the prevention and treatment of skin infections, and the treatment of wounds. Iodine has been recognized as an effective broad-spectrum bactericide, and it is also effective against yeasts, molds, fungi, viruses, and protozoans. Drawbacks to its use in the form of aqueous solutions include irritation at the site of application, toxicity, and the staining of surrounding tissues. These deficiencies were overcome by the discovery and use of PVP-I, in which the iodine is carried in a complexed form and the concentration of free iodine is very low. The product thus serves as an iodophor. In addition, it has been demonstrated that bacteria do not develop resistance to PVP-I, and the sensitization rate to the product is only 0.7% Consequently, PVP-I has found broad application in medicine as a surgical scrub; for pre- and post-operative skin cleansing; for the treatment and prevention of infections in wounds, ulcers, cuts and burns; for the treatment of infections in decubitus ulcers and stasis ulcers; in gynecology for vaginitis associated with candidal, trichomonal or mixed infections. For these purposes PVP-I has been formulated at concentrations of 7.5–10.0% in solution, spray, surgical scrub, ointment, and swab dosage forms. It is available without a prescription under the generic name povidone-iodine or the brand name Betadine. It is used in pleurodesis (fusion of the pleura because of incessant pleural effusions). For this purpose, povidone-iodine is equally effective and safe as talc, and may be preferred because of easy availability and low cost. 2.5% buffered PVP-I solution can be used for prophylaxis of neonatal conjunctivitis (''Ophthalmia neonatorum'') which can lead to blindness, especially if it is caused by ''Neisseria gonorrhoeae'', or ''Chlamydia trachomatis''. PVP-I appears to be very suitable for this purpose because unlike other substances it is efficient also against fungi and viruses (including HIV and ''Herpes simplex''). PVP-I can be loaded into hydrogels (based on carboxymethyl cellulose, poly(vinyl alcohol) and gelatin, or on crosslinked polyacrylamide). These hydrogels can be used for wound dressing. The rate of release of the iodine in the PVP-I is heavily dependent on the hydrogel composition. The release rate increases with more CMC/PVA and decreases with more gelatin. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Povidone-iodine」の詳細全文を読む スポンサード リンク
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