Updated: Dec 3, 2020
>The virucidal activity of povidone iodine is directly dependent on the level of molecular iodine (free iodine) present.
>Molecular iodine is present in povidone iodine at only trace levels (1-3 ppm)
As stated by Biocontrol Sciences, 2016, Vol. 21, No 1, 21 - 27. Povidone-iodine solutions prepared to various concentrations（0.01, 0.1, 1 and 10%）with 0.2M phosphate buffer (pH 7.0）PVP-I PB were analyzed to determine their free iodine concentrations using membrane permeation cells, and their inactivation effects on three viruses (influenza A virus, poliovirus type 1 and adenovirus type 3) were examined. The free iodine concentrations in the 0.01-10% PVP-I PB were determined to be 1.84, 4.88, 1.58 and 0.17 ppm (approximate values, respectively, with the maximum obtained for the 0.1% solution.
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