316 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Modern cosmetic chemistry owes a big share of its success to dermatology and pharmacy. When it comes to preparations with special effects like deodo- rants, ache creams or sun protection agents, the borderline between cosmetic and medical topics is not easily defined because the same active substance or formula may be used by the dermatologist and sold over the perfumers coun- ter as well. This situation of today ist not a one way path and vice versa cosme- tic research has made no small contribution to dermatology. Hadgraft (1) sees the cosmetic chemist's r61e in providing more detailed knowledge on percutaneous absorption and in improving the cosmetic accep- tability of dermatological preparations. From this more effective topical medi- caments are developed, due to better knowledge of skin penetration. We have found that regardless of these points, the cosmetic concept of a drug will lead to better medical results, simply by making it pleasant to the patient to apply and regularly reapply a certain product .The frequency of reapplication besides drug composition is also listed by Barrett (2) as one of the important factors influencing skin penetration. He additionally mentions the importance of skin hydration for the dermatological success, a problem which cosmetically composed preparations usually deal with. The streamlining of dermatological products has had precursors in other me- dical fields and most likely the need to facilitate oral application of large quan- tities of modern chemotherapeutics to babies can be considered as the starting point. Serious efforts, to give drugs in general a better taste were initially ta- ken up in the United States (3) but today also among European patients many drugs have lost their reputation of disagreeably tasting benefactors (4). It is interesting to note that there exists a definite relation between the general standard of living of a people, the availability of,,tasty" medicines and its use (s). To illustrate the necessity of a cosmetic approach to a new topical prepara- tion we want to present some examples from different fields of dermatology. The main pharmaceutical products used in treating common foot affections like mycoses or hyperhidrosis are either powders or organic solutions con- taining e.g. smelling tar derivatives, strongly staining substances, sometimes a certain proportion of oil and film forming or fixing substances. The applica- tion is usually directly on the bare skin and rather inconvenient and messy. As a result, regular or frequent treatment with these compounds will automati- cally decrease as soon as the ailments have become less troubling in many ca- ses however, before the healing process ist really on its way. If this problem is to be resolved by cosmetic approach which means to ma- ke the product pleasant and easy to use, the first step of course is to prepare an aerosol. But consulting the cosmetic literature (6) (7) one finds mainly the pow-

TOPICAL PREPARATIONS 317 der spray which is neither more pleasant nor less messy than a powder and has the disadvantage of valve troubles. We think that in a successful foot spray one must omit any powdery sub- stances and leave the drying, absorbing effect, which is a rather doubtful busi- ness anyhow, to the stockings, which have to be of adequate fabric, and should be changed daily. Furthermore there are today quite a few colorless, odourless, easily soluble bactericidal and fungicidal substances which in com- binations with cooling and freshly smelling compounds form the active ingre- dients. Most important in the cosmetic concept is the right choice of the liquid vehicle because it has to be designed to permit application through the socks or stockings so that the user simply takes his shoes off and sprays directly on his clad feet (8). This involves formulation of a wet spray, use of easily evapora- ting, nongreasy solvents, that do not attack the textile fibres, avoiding of fix- ing agents and accompanying substances that do not easily wash out. Finally, but all to often forgotten, the solvent mixture may not give any burning or itching sensation nor disagreeable cold by rapid evaporation. Therefore hydro- philic vehicles are preferred that are diluted with water to a certain extent. This again implies the use of solubilizers and surface active agents simulta- neously assuring even spreading of the preparation on and between the toes. In vitro tests of such a product will not show marked superiority over a conventional prescription in daily use however the cosmetic composition leaves the other onefar behind in its success, due to better customer acceptance. The ageing of the human skin, especially of uncovered areas of the body is partly due to the permanent influence of ultraviolett light. At the German Cosmetic Chemists Annual Conference in 1964, H. Tronnier (9) has drawn the attention to the longer wave range of the ultraviolett up to the near visible as an important cause for the process of accelerated skin degeneration. This assumption could be confirmed by various researchers (e.g. 10) and has also led to the development of cosmetic skin care products especially designed to prevent light-induced early skin ageing (11). In the course of this development work the problem of reliable and rapid testing of these preparations had to be solved, since the field test, which means the cosmetic use under regular observation would have taken years. Of course there was the possibility of spectrophotometric measurement of the creams, but it is common knowledge that a real assessment of light absorbing products can only be made on the skin, of late pointed out by Kahn and Wilcox (12). The prevention of the slow process of skin degeneration caused by chro- nic UV-A range influence could not be verified within a reasonable period. So we looked for acute, clearly manifesting pathological skin reactions induced by the same wavelengths.