POLYVINYLPYRROLIDONE IN COSMETICS 131 solution in the other case. A contact time of approximately 40 minutes was permitted to elapse. After 40 minutes a small sample of the hair was removed from each tube and the rest of each hair sample was trans- ferred to tubes •)f water. The transferred hair samples were then agitated intermittently for a period of five minutes. A sample of hair from each tube was once again removed and the bulk of the hair samples in each case were then transferred to another tube containing water. In this fash- ion, the Actaruer treated and PVP-Actamer treated hair was washed and sampled for a total of four times, so that there were four hair samples and four washings in each case at the. completion of the successive washing procedures. The above hair samples and washings were then tested for residual Actamet. Staphylococcus aureus agar plates were prepared. Tufts of the above hair samples were placed in the seeded agar just be- fore it hardened. The washings from the same hair samples were added to cups cut in the previously hardened agar in the usual fashion. The results of the above run follow: SIZE OF ZONES OF INHIBITION OF S. aureus •. PVP-Actamer • I-- Actamer • Sample Washings Washings Washings Washings No. Cup Plate Hair Plate Cup Plate Hair Plate 1 8 mm. 40 mm. complete 8 mm• 30 mm. plate 2 5 mm. 8 mm. 7 mm. 4 mm. 3 1 min. 2 mm. 3 min. 0 4 0 2 mm. 1 mm. 0 On the basis of the above results, the successive washings of Actaruer treated hair give greater zones of inhibition than the successive washings of PVP-Actamer treated hair. Likewise, the Actaruer treated hair itself shows a more rapid elution of Actamer by successive washings than does the PVP-Actamer treated hair sample. It follows from the above that PVP results in a more firm fixation of the Actamer. The carrying or solubilizing effect of the PVP was also demon- strated by casting films of Actaruer onto glass slides, from alcoholic solu- tions and from alcoholic PVP solutions. Likewise, hair was treated by spraying with alcoholic Actaruer and alcoholic PVP-Actamer solutions. The alcoholic Actamer solution evaporates with the fortnation of crystals and amorphous precipitates of Actaruer directly on the hair shaft, and on the surface of the glass slides. The alcoholic PVP-Actamer evaporates without any visible precipitate forming on either the surface of the slide or the surface of the hair. Instead a perfectly transparent film is fortned. The above phenomena are effective at low concentrations of the PVP (e.g., 0.5%) since evaporation of the solvent takes place when the hair is sprayed.

132 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS It is to be pointed out that the action of PVP on hair and skin, and its substantivity to these materials cannot be explained entirely by the "embathische effekt" (as described in the German literature). Utilizing this effect, one polymeric substance passes through another polymeric substance, carrying with it substances which normally are not transported through the same substrate. We have found that in the dying of hair, PVP may either favor fixation of the dye molecules to the hair, or it may minimize the penetration of the hair by the dye, depending upon the method of application. The opportunity to study a material such as PVP is not presented very often. There are few chemicals which have the wide range of desirable properties inherent in PVP. These properties make this material most adaptable for use in pharmaceuticals, foods, and cosmetics. PVP may almost be considered to be a synthetic protein. In its activity it behaves primarily like a protein except that it does not possess the undesirable properties of protein such as its allergenic, antigenic, or depressor releasing effect. It also does not react with certain protein precipitants. It is with the above information in mind that we feel indeed fortunate in being able to present some of the attributes of PVP to you.