POLYVINYLPYRROLIDONE IN COSMETICS 209 (iii) Shampoos The incorporation of polyvinylpyrrolidone into shampoos has been suggested, jø the advantages claimed being improved foam stability and an enhanced lustre on the hair owing to a residual film of po!yvinylpyrrolidone after rinsing. American workers have also claimed that the incorporation of polyvinylpyrrolidone can reduce eye irritation, particularly in shampoos containing antiseptics. (iv) Hair Dyes and Bleaches The final suggested applications of polyvinylpyrrolidone in hair prepara- tions are surprisingly near the established uses in the textile industry. It has been mentioned earlier that polyvinylpyrrolidone forms complexes with many dyestuffs, and it has been shown that when dyeing hair, carrying out this operation in the presence of polyvinylpyrrolidone can result in the polymer being deposited on the hair preferentially, the polymer film then taking up the dyestuff. The Shelanskis 6 have suggested this phenomenon can be used to provide either more permanent tints on the hair or alternatively temporary colourings which can easily be washed out on shampooing. This appears paradoxical, but apparently is bas,ed on different polyvinylpyrroli- done concentrations and different modes of applicatio n . Almost certainly different types of dyestuffs are involved, but no experimental details have been published. An interesting variant of this has recently appeared on the market, both in the U.K. and in the U.S.A., • in the •form of coloured polyvinyl- pyrrolidone hair lacquers. These have the virtue of providing stable tem- porary tints which can be applied to the hair at the same time as the lacquer and can be readily removed with the lacquer by shampooing. Presumably the advantage is that the hair is never actually dyed, and so cannot become damaged. The use of polyvinylpyrrolidone with hydrogen peroxide for hair bleaching has also been suggested in America, where it has been claimed* that the polyvinylpyrrolidone stabilises the hydrogen peroxide solution to give a more effective bleaching agent operating in the absence of either ammonia or ammonium salts. (c) Pre-shave and After-shave Lotions Polyvinylpyr, rolidone is also being used in both pre-shave and after- shave lotions, particularly those for •aerosol a. pp•lica{ion, although this expensive method of ,packing hardly seems essential. 'Typical after-shave lotions are based on about i per cent poly•inylpy,rrolidone in 85 per cent ethyl alcohol, together with perfume., Such products can 0b¾i,ously 'be packed in glass aerosol containers if desired. 12 The polyvinylpyrrolidone is

210 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS said to reduce somewhat the sting of the spirit and to leave a smooth, slight film on the skin. In pre-shave lotions for use with electric razors the inclu- sion of polyvinylpyrrolidone should assist in conditioning the hair for shaving and again would leave a smooth film on the skin. 8 (d) General Make-up So far we have discussed applications of polyvinylpyrrolidone which result in the deposition of a transparent film. Apart from its excellent film-forming properties polyvinylpyrrolidone is also an excellent pigment binder and dispersing agent, and it is therefore not surprising that it has found application in the formulation of liquid make-up, pancake, compressed powder make-up and mascara. Such applications so far appear to have particularly aroused interest in Germany, and it has been claimed that such make-up leaves the skin smooth to the touch. In mascara I understand that the use of polyvinylpyrrolidone can result in a non-eye irritant prepara- tion, but I believe that this can now be achieved by other means as well. It has been mentioned earlier, when discussing hair creams, that polyvinyl- pyrrolidone is an excellent emulsion stabiliser, and can therefore be used in the formulation of toilet emulsions, including pigmented emulsions such as tinted foundation creams. The use of polyvinylpyrrolidone in hormone cosmetic creams has been patented •9 and the polymer may also find possible applications in the formulation of special purpose barrier creams. TM In America they appear to be showing interest in the use of polyvinyl- pyrrolidone in lipsticks and in nail polish removers. The former application is possibly associated with polyvinylpyrrolidone's ability to form dyestuff complexes the latter use is not fully understood. (e) Shaving Creams The use of polyvinylpyrrolidone in shaving creams has also been sug- gested, •' particularly for use in aerosol packs. One would expect that such shaving creams would leave the skin feeling particularly smooth, and in addition, as mentioned earlier under shampoos, the polymer is' an excellent foam booster and stabiliser. (f) Tooth Pastes On the fringe of the toilet preparation class of product I would mention that the use of polyvinylpyrrolidone in tooth pastes has been patented. •8,•7,• It is claimed that the polymer's complexing ability assists in the removal of tartar and in removing tobacco stains. It has also been suggested that polyvinylpyrrolidone can be used with advantage in the formulation of chlorophyll-containing tooth-paste.