NEW TRENDS IN COSMETIC EVALUATION By Lou•s C. BAP. AIL* Presented December 2, 1959, New York City •]7ESTS FOR PERFORMANCE •tnlytical Methods Son•. o•D analytical methods which have proved their usefulness are still in use, for instance the determination of the iodine number and several titration methods. However, in the recent years, more importance has been given to proc- esses using special instruments. Among them is colorimetry. New calorimeters of great precision have appeared on the American market dur- ing the past ten years. New methods have made their use much easier and speedier. Qualitative and quantitative analyses are almost routine and permit the determination of a great many chemicals. Fluorometry is used more than ever and is the choice technique for vitamins, hormones, alkaloids, biological and microchemical analyses. So is chromatography very valuable in the fields of insecticides, antiseptics and other chemicals. It also enables the separation of hydrocarbons. Spectrametric and spec- tragraphic analyses are now made with huge precision instruments which leave far behind the small and medium size spectragraphs which were found in the analytical laboratories of yesteryear. They play a great part in analytical microchemistry in cosmetology. All these methods are the tangible proof of the present trend in cosmetic chemistry: to evade mere routine and empirism and to replace them with methods having a true scientific background, giving proved reproducible results of great accuracy and leaving nothing to approximation and imagina- tion. As we will see later, too many empiric test methods have been used in the past. Some are still in favor in old-fashioned laboratories, nobody knows why except their archaic users, but they are definitely on the way out for good. Among other valuable tests we shall also mention photography, and par- ticularly microphotography. These fields are definitely outside the realm of cosmetic chemists, although a few of them are excellent amateur pho- * Consulting Biochemist and Toxicologist, New York 36, N.Y. 24l

242 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS tographers. However, a great deal of experience is required for the micro- photography of skin cells, hairs, chemical particles and other objects of interest to a cosmetic chemist, or a research biologist. We feel very sad to have to admit that there are not enough first class microphotographers, and very often, we had to resort to medical art illustration to replace microphotographs which were much too poor to have any informative value. Electrobiology Two electrobiological methods, relatively new in cosmetic chemistry de- serve a special mention. The purpose of both of them is to insure artificial penetration of substances through living tissues. The first one, electron- osmosis, produces a highly localized penetration of the skin or mucous membranes. The second one, iontophoresis penetrates much deeper. Electronosmosis. As the name implies, electronosmosis consists of charg- ing particleg of matter with electrons, and having them bombard living tissues, thus chasing the carried element into the first layers of the tissues. The penetration increases with the intensity of the current, while the amount of chemicals caused to penetrate increases with the duration of the application. Any substance can be made to migrate this way for instance, antibiotics and antiallergens such as Pyribenzamine penetrate just as well as tincture of iodine or a solution of zinc sulfate. Electronosmosis, besides its numerous therapeutic applications has been used in cosmetic research projects dealing with deodorants, antiperspirants, facial creams containing vitamins or hormones, lipsticks and a few others. lontophoresis. Iontophoresis consists in the artificial penetration of an ionized element. For instance, instead of causing the penetration of sodium chloride such as electronosmosis would do it, iontophoresis causes either sodium or chlorine to migrate as ions. When complex formulae are used, the technician selects the proper ion to be carried and uses the proper pole accordingly. Iontophoresis has been mostly used in the study of deodorants, anti- perspirants and dentifrices. Brun and Barail have published several papers on the use of electrobiology and electropenetration in cosmetic research. Odor Measurements What would you say if someone would tell you that he walks at the same speed as a DC3 and the turtle in his garden also walks at the same speed? You would certainly tell this person that he is completely stt•pid. Yet, according to some cosmetic testing methods, you would be wrong, very wrong indeed and he would be perfectly right. He would be merely dividing the speeds of various ways of transportation into four categories of 250 m.p.h. each from 0 to 1000 m.p.h. Therefore, he and the small airliner would be in the same speed class of 0 to 250 m.p.h. and therefore could be