POLYVINYLPYRROLIDONE (PVP)mA USEFUL ADJUNCT IN COSMETICS* By HER•^N A. S.Et,^NsKI, PvI.D., Mov, RIs V. SvI•t,^NsKI, M.D., and A. C^NToa, P•.D. Industrial Toxicology Laboratories, Philadelphia ¾, Pa. POLYVINYLPYRROLIDONE (PVP) was developed in Germany by Reppe within the past twenty years. The material was one of a great many products produced by the Reppe process in acetylene chemistry. PVP (Polyvinylpyrrolidone abbreviated) was studied in many appli- cations, among which was its use as a blood plasma extender in World War II by the Germans. Subsequent to 1945, this material has been made and studied in this country for use as a blood plasma extender and is now enjoying widespread use in the pharmaceutical and cosmetic in- dustries. PVP is an inert, white material. It is non-toxic by acute oral adminis- tration, by skin absorption, by inhalation, by intravenous or by intra- peritoneal injection. The LD0 of PVP is over 100 gm./kg. PVP has been studied among humans on skin application and has been found to be neither a primary irritant, a skin fatiguing material, nor a sensitizing material when tested by the Schwartz or the Shelanski method. Because of its extremely low toxicity, its use in the pharmaceutical field was indicated from the very start. It is only a stone's throw from something which has been found useful in the pharmaceutical field, and which is non-toxic, to the cosmetic field where the same material might have application. The properties of PVP which made it especially useful in the cosmetic field have been investigated by the authors. These prop- erties specifically are solubilization, desensitization, detoxification, and substantivity. The phenomena which PVP displays in carrying relatively insoluble materials into a solution is beyond the scope of this paper. However, an interesting example of this phenomenon is solubilization of elemental iodine forming the PVP iodine complex. This is an example of a solid solution. It has also been shown that many water-insoluble materials ranging from basic elements to saccharides and proteins are rendered more soluble in * Presented at the December 10, 1953, Meeting, New York City. 129

130 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS the presence of PVP. Also PVP prevents separation of cosmetic preparations by acting as a suspending agent to many materials which it cannot carry into water solutions. PVP, when studied in shampoos, acts as a foam stabilizer. PVP has the property of reducing the intensity or delaying the inception of primary irritant effects of many irritants on the skin. The authors have tested over 100 materials commonly used in cosmetic preparations and have found that in the majority of these, the irritant properties are minimized by PVP. For example, both so- dium alkyl sulfonate and sodium N-lauroyl sulfonate tested in a 1% solu- tion by means of the repeated insult patch test study technique showed lq- reactions beginning as early as the third application. Following the fifth application, 2+ reactions occurred in some subjects. However, the same solutions with 1% PVP added, produced no irritation until af- ter the seventh application. The intensity of these reactions remained at the 1 q- level in a greater number of the subjects tested. The detoxifying effect of PVP is something that is made use of consider- ably. The PVP iodine complex referred to previously is a good example of the detoxification of a highly toxic material, namely elemental iodine. The toxicity of iodine is reduced in effect from an approximate LD0 of 150 mgm./kg. to 1500 mgm./kg. PVP will also reduce the toxicity of mercury, nicotine, cyanide, and other such toxic materials. Among the desirable attributes of PVP is the property of substantivity. By substantivity, in this case, is meant the affinity of the PVP for various types of materials, which affinity cannot be explained simply by absorp- tion or adsorption. We might further qualify this phenomenon of substan- tivity as a special type of irreversible adsorption. When hair is placed in contact with PVP solution, or if the PVP solu- tion is added to the hair, certain amounts of the PVP enter into the hair shaft. Subsequent rinsing of the hair does not remove all the PVP which is apparently combined with elements of the lumen of the hair shaft. On microscopic examination, it is apparent that the hair takes on an improved appearance, and an increased clarity, accentuating the natural color. The hair appears to be smoother. Qualitative studies were performed to show that the PVP is present in the hair. By utilizing the PVP iodine phenom- enon it is easy to demonstrate the presence of PVP in the hair by adding a weak iodine solution (Lugols). Enough of the iodine is absorbed by the PVP to give it the mahogany color which is characteristic of the PVP iodine complex. After these hairs are washed, the residual PVP-iodine complex retains its germicidal nature. A further illustration is to be seen in the combination of Actamer and PVP. Five-tenths per cent Actamer dispersions were prepared with and without 5.0% PVP. Thoroughly washed hair (soap and water wash) was added to the Actamer solution in one case, and to the Actamer-PVP