Abstract: Preparation of free-flowing granules of practically uniform composition and particle size consisting essentially of poly-N-vinylpyrrolidone and iodide (I.sup.-) by combining with uniform thorough mixingA. a solution and/or colloidal suspension of a substance releasing iodide ions in a first solvent or solvent mixture, as well asB. a solution and/or colloidal solution and/or suspension of PVP in a second solvent or solvent mixture which possesses a surface tension different from that of the first solvent or solvent mixture, and in which PVP is at least partially soluble or wettable, and in which the substance releasing iodide ions, contained in the first solvent or solvent mixture, is insoluble or only slightly soluble;And separating and drying the granules formed.