Manufacture of aqueous polyvinylpyrrolidone-iodine solutions

A process for the preparation of a stable aqueous solution of PVP-iodine which comprises:

• mixing in an aqueous medium
• (a) PVP as an aqueous solution of from 10 to 60% strength by weight, wherein said PVP has a K value of from 8 to 50 and has been prepared in the form of an aqueous solution by the steps of
• (1) polymerizing vinylpyrrolidone in an organic solvent which is an aromatic hydrocarbon or a lower aliphatic monohydric alcohol of 1 to 4 carbon atoms at a concentration of monomer of from 10 to 80% by weight and in the presence of a free radical initiator which is an organic per-compound selected from the group consisting of alkyl hydroperoxides and dialkyl peroxides of 1 to 8 carbon atoms per alkyl and per esters in an amount of about 0.1 to 5% by weight, based on vinylpyrrolidone,
• (2) mixing the resulting solution of PVP in the organic solvent with water,
• (3) distilling off the organic solvent to give an aqueous solution of PVP, and
• (4) treating the aqueous solution of PVP with steam in the amount of from 20 to 200% of steam based on the weight of PVP;
• with
• (b) iodine in an amount of from 5 to 60% by weight, based on PVP;
• and with
• (c) a compound which provides iodide ions in an amount of from 10 to 200% by weight, calculated as iodide ions and based on the amount of iodine employed.