An Iodophor is a preparation containing iodine complexed with a solubilizing agent, such as a surfactant or povidone (forming povidone-iodine). The result is a water-soluble material that releases free iodine when in solution. Iodophors are prepared by mixing iodine with the solubilizing agent; heat can be used to speed up the reaction.
Free iodine kills the eukaryotic or prokaryotic cells by iodination of lipids and oxidation of compounds in the cytoplasm and cell membrane. Unlike with some antibiotics, microbes do not develop resistant strains against iodine. However, iodine is an irritant to mucous membranes and corrodes medical instruments. Iodine also kills live cells of mammals. Therefore, a slow release in smaller concentrations is desirable for patient use.
In iodophor formulations free iodine is released slowly from the carrier molecules, and thus are more gentle to the skin and have increased shelf-life. Effectiveness of any iodophore depends on active free iodine percentage. Percentages greater than 3.5% have no additional advantage.
Despite of all these advantages, iodophores must be used under technical supervision. Many cases of toxicity and adverse reaction have been reported.
Diluted iodophor is often used by homebrewers and home wine makers to sanitize equipment and bottles. Its major advantage over other sanitizers is that when used in proper proportions it sublimates directly from solution to gas, and hence leaves no residues. It is also non-toxic to humans and therefore especially suited to food processing applications. It is cheap and effective, but it can leave unattractive orange-brown stains on plastic parts and equipment that it is left in contact with.
It is often supplied in different concentrations and is further diluted with water before use. The label will advise the appropriate dilution rate, commonly 1:1000 or 1:100. Equipment to be sanitized should be thoroughly clean and left in contact with the solution for at least 2 minutes.