EVALUATION OF IN-VITRO AND IN-VIVO METHODS OF TESTING DEODORANTS WITH PARTICULAR REFERENCE TO CHLOROPHYLL AND ITS DERIVATIVES* By Jox-xN A. K•LL•^N, Ph.D. New York, N.Y. THIs REPORT has been pre- pared with two objectives in mind. The primary objective was the pres- entation of a few series of experi- mental studies which had been selected as representative of both in-vitro and in-vivo methods of evaluating the comparative effi- ciencies of deodorants. Both types of experimental procedures have been adapted to determinations of the deodorant actions of chlorophyll and some of its derivatives. A discussion of the potentialities and limitations of chlorophyll and its derivatives as determined by in- vitro and in in-vivo methods, was the second objective to which this report has been directed. Throughout all subsequent dis- cussions, the term "deodorant" has been used to define chemical compounds or preparations which possess capacities either to inhibit developments of odors and/or to eradicate pre-existing odors. * Presented at the May 18, 1951, Meet- ing, New York City. INTRODUCTION Two principal considerations de- termined the selection of the series of experiments for presentation in the following tables and charts, viz. (a) the fact that the sources of the malodorous compounds, utilized for test purposes, were amenable to the inhibitory or deodorizing actions of cosmetic preparations and (b) the fact that the experimental procedures yielded results which were utilizable as premises for esti- mates of comparative efficiencies of deodorants under actual conditions of use. Inasmuch as all of these sources of odors are either inter•mediate or end products of metabolism taking place within the human body or the resultant products of metabolism of microiSrganisms resident upon the body's surface, the odors have been classified as "biological." The sole purpose of this descriptive classification is to differentiate odors originating in the body or on its cutaneous surface from those de- rived from extraneous sources. 3O

TESTING DEODORANTS WITH CHLOROPHYLL AND DERIVATIVES 31 Biological odors may be sub- divided into two major categories: (a) the metabolic or endogenous odors and (b) the perspiratory or exogenous odors. Odors originating in the mouth or exhaled through the respiratory tract, fecal odors, odors derived from metabolites excreted in urine and odors produced in the vagina are typical examples of metabolic odors. However, dis- cussions in this report will be limited to the sources of odors which are or may be eliminated through the skin. In their identifications of samples of mixtures of liquids and suspended solids which had been collected from skins of human subjects, many authors of publications in clinical and physiological literature have used the words "sweat" and "per- spiration" as synonymous terms. This laxity in nomenclature is de- plorable inasmuch as it has given rise to states of misapprehension and confusion in reference to the chemi- cal composition of the excreta of the skin as distinguished from the diverse constituents of the cu- taneous mantle many of which have been derived from extraneous sources. As a prerequisite to an intelligen t appreciation of the differ- entiation between metabolic odors eliminated through the skin and the putrid odors resulting from putre- factire reactions initiated by bac- teria in the cutaneous mantle, it was deemed advisable to give suc- cinct definitions of the term "sweat" and "perspiration" as they have been used throughout this report. Sweat is the mixture of excretory products, including water, of the coil glands (or eccrine glands) of the skin. Since the collection of pure sweat in quantitiek adequate for comprehensive analyses presents many practical and frequently in- surmountable difficulties (1), the accumulated knowledge of the chemical composition of this excre- tion is, at best, very fragmentary. All that is known concerning the constituents of sweat may be sum- marized briefly in the following statements. Sweat has a specific gravity only slightly greater than that of distilled water (between 1.001 and 1.0015) it contains prac- tically the same metabolites as does the urine but in significantly lower concentrations the principal solid components are sodium chlo- ride, sugar, urea, ammonia, amino acids, lactic acid, uric acid, phos- phates, and sulfates (2, 3, 8, 9, 10, and 11). Excretory functions of the sweat glands are very responsive to incre- ments in body temperature resulting from either rises in temperatures of the environment or increases in internal temperature of the body. The critical range of skin surface temperature, at which the acceler- ated rate of excretion of sweat re- sults in the accumulation of gross moisture on the skin's surface, is between 33 ø and 33.5 ø C. (4 and 5). Thermal stimulation of sweating is the procedure which has been adopted by most experimentalists for purposes of collecting sweat (2 and 6). Although samples col-