PVP-Iodine is a stable chemical complex of polyvinylpyrrolidone (PVP) and elemental iodine^3-5.

Solubility

PVP-Iodine, Povidone-Iodine, is completely soluble in cold water, in amounts up to and exceeding 10% (1% available iodine). By contrast, elemental iodine is water soluble only to 0.034% at 25°C. PVP-Iodine is also soluble in ethyl alcohol, acetone,
polyethylene glycol and hydroxyethylpyrrolidone.

Stability

PVP-Iodine can be stored in powdered form without significant iodine loss. Samples kept for three years at 65°C in glass stoppered bottles without tape or seal showed only 0.5% maximum loss of available iodine. The product should, however, be protected from moisture.

Published data show the stability of PVP-Iodine solutions is vastly superior to that of iodine tincture or Lugol's solution.

Compatibility

PVP-Iodine dosage forms have been compounded successfully as powders, tablets, liquids, lotions, ointments, gels, and sprays. If the vehicle or base reacts with iodine, then the available iodine in the final preparation must be determined, since the germicidal activity of the finished product is dependent on the iodine, not the iodide content.

PVP-Iodine systems should be mildly acidic since alkaline solutions, including ammonia, and reducing agents lower the available iodine which, in turn, results in lower antiseptic activity. PVP-Iodine is compatible with steel, wool and plastic, but reacts with silver.

Biocidal Activity

For many years iodine has been recognized as an effective broad spectrum biocidal agent⁶. The irritancy and toxicity associated with its use have been significantly reduced by using PVP-Iodine. Because of the product's wide usage and established efficacy, it is presently included as an antiseptic agent in the United States Pharmacopeia as well as in many other national compendia.

Biocidal agents have been classically measured for effectiveness by the use of in vitro methods. In vitro results, however, should be considered only as preliminary measures 'of “cidal” efficacy. Factors such as skin penetration and reactivity can completely reverse any effectiveness rating determined by purely in vitro test methods.

The in vitro biocidal activity of PVP-Iodine has been studied for years against bacteria, yeast and molds, actinomycetes and rickettsia⁷. See in Table.

There have also been reports that PVP-Iodine is effective as an antiviral agent.