J. Soc. Cosmetic Chemists, 18, 769-775 (Dec. 9, 1967) Hand Degerming Evaluation Utilizing A Split-Use Method JAMES BROWN, JR., M.S., RONALD .J. ERIKSSON, B.S., FRANK YACKOVICH, Ph.D., and DAVID TABER, Ph.D.* Presented November $0, 1066, New York City Synopsis--Utilizing a modified split-use method, two baeteriostatie soaps were evaluated for their utility in degerming the hands. One soap contained 0.75% (by weight) of hexaehloro- phene and 0.75• of 3,4,4'-triehloroearbanilide the other consisted of equal parts by weight of 3,5-di- and 3,4', 5-tribromosalieylanilides, 4,4'-diehloro-3- (trifiuoromethyl)earbanilide, and 3,4,4'-triehloroearbanilide for a total concentration of 2%. A significant reduction in bac- terial counts was achieved by both soaps as compared to a nonmedicated soap. It is empha- sized that rigorous handling of data requires that the confidence interval be identified xvhen per cent reduction is used as a basis for describing degerming efficiency. INTRODUCTION To investigators in the field of soap germicides, many techniques are available for evaluating skin degerming after use of an antibacterial soap. Among these are clinical observations, tape strippings, swab methods, contact plate methods, and plate counts obtained from hand- washings. Four of these methods involve counting bacterial colonies, while clinical trials involve observations of the progress of bacterial dis- eases of the skin. The moderation or the prevention of skin diseases is one of the at- tributes of an effective bacteriostatic soap. However, for the initial evaluation of a new bacteriostatic system in soap, the length of time needed for a meaningful clinical study makes this tool of questionable value. * Armour Grocery Products Company, 3115 S. Benson St., Chicago, Ill. 60609. 769

77O JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Tape stripping as used by Updegraff (1) involves applying an ad- hesive tape to the skin surface then removing the tape with an adhering layer of skin containing colonies of bacteria. This method allows one to determine the distribution of bacterial colonies in relation to area and depth of the epidermal layers. Skin swabbing (2) is performed with cotton or calcium alginate swabs. The swabs are placed in water or hexametaphosphate solution, the suspension is shaken thoroughly to distribute the organisms, and an aliquot is plated bacteriologically. Variations in bacterial counts can occur because of nonreproducibility in the pressure used in applying the swabs to the skin and because the number of bacteria removed from the swabs may vary with the e•ciency of the shaking. A more reproducible swabbing technique is utilized by Pachtman, et al. (3). An aliquot of a 0.1ø-/o aqueous solution of Triton X-100 ©* is piperted into a glass cylinder 23 mm in diameter pressed firmly against the skin. The skin is abraded gently with a glass rod or Teflon police- man for two minutes, then the solution is removed, diluted, and plated bacteriologically. Contact plates are made by adding liquefied nutrient agar to a Rodac plate• or small container, allowing the agar to harden, then pressing the plate with uniform pressure to the skin area to be tested. Plates are incubated at 37 øC for 48 hours, whereupon colonies are counted. Ulrich (2) stated that the method is reproducible for the first five plates taken sequentially from the same area of skin. Only bacteria on the surface of the skin are enumerated by this method. This paper deals primarily with handwashing as a technique for eval- uating skin degerming. Price (4) developed a procedure whereby bacteria are removed from the hands and forearms by scrubbing with a surgical scrub brush in a series of basins containing a standard volume of water. Bacteria are removed at a decreasing rate as determined by counting the bacteria in each basin, plotting a curve which can be used to calculate the total bacterial flora on the area tested. Counts are taken on ten to fourteen basins. If an antibacterial soap is used, the reduction in bacterial count as compared to the number obtained when a nonmedicated soap is used gives a measure of the effectiveness of the antibacterial product. * Iso-octyl phenoxy polyethoxy ethanol. Registered trade mark of Rohm & Haas Co., Philadelphia, Pa. t Distributed by Baltimore Biological Laboratories, Inc., Baltimore, Md. 21218.