Wikipedia
Povidone-iodine (PVP-I), brand name Wokadine, Pyodine, and 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.
This unique complex was discovered in 1955 at the Industrial Toxicology Laboratories in Philadelphia by H. A. Shelanski and M. V. Shelanski. 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.
It is on the WHO Model List of Essential Medicines, the most important products needed in a basic health system.