J. Soc. Cosmet. Chem., 32, 223-229 (July/August 1981) Percutaneous penetration of hair dyes HOWARD I. MAIBACH, Department of Dermatology, School of Medicine, University of California, San Francisco, CA 94143 and LESZEKJ. [VOLFRAM, Clairol Inc., Stamford, CT 06922 Received May 21, 1981. Synopsis Scalp penetration of diaminoanisole (DAA), p-phenylenediamine (PPD), and N4,N4-Bis-(2-hydroxyethyl)- N'-methyl-2-nitro-p-phenylenediamine (HC Blue #1) that occurs under conditions of hair dye usage was evaluated for both Rhesus monkey and man using •4C labeled materials. Both species showed a remarkably similar pattern of dye penetration. Thus the average dose excretion of DAA in the Rhesus monkey was 0.02% and in man 0.015% PPD excretion in monkey and man was 0.14% and HC Blue #1 excretion in the monkey was 0.12% and in man, 0.09%. INTRODUCTION Hair dyes have been in use for several decades yet even recent studies of their skin penetration potential have been restricted primarily to their evaluation in rats and dogs (1-4). Although useful, these results are difficult to relate to man and thus the uncertainty as to •the extent of penetration under practical use conditions of the fully formulated products continues. Kiese and Rausher (5) studied the absorbtion of p-toluenediamine in human skin but their analytical approach, based on the excretion in vivo of N,N'-diacetyl-p-toluenediamine, did not allow for conclusive quantification of the penetration data. Qualitative studies in man suggested that penetration occurred but could offer no quantitation (6). Subsequent investigation raised the question of whether thin layer chromatographic data were real or artifacts (7). We have conducted investigations into the percutaneous absorbtion in vivo of three commonly used hair dye ingredients in rhesus monkey and man. The methodology was patterned after the procedure developed by Feldmann and Maibach (8) for measurement of percutaneous absorbtion in man. This method involves quantifying absorbtion on the basis of the percent of radiactivity excreted in the urine for at least five days following application of a known amount of the labeled compound. EXPERIMENTAL 1. DYE PREPARATION. Commercially available hair dye products were labeled with radioactive materials (ICN Pharmaceuticals, Inc., Irvine, CA). Oxidative hair colors were enriched as follows: 223

224 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 2,4-diaminoanisole (DAA, ring •4C, specific activity 104/xCi/mg) was added to Miss Clairol Creme Formula//52, Black Azure, containing 1.74% DAA p-phenylenediamine (PPD, ring •4C, specific activity 203 /xCi/mg) was added to Nice'n Easy//124, Blue Black, containing 2.7% of PPD. Semi-permanent hair color was enriched with N4,N4-Bis-(2-hydroxyethyl)-N'-methyl-2-nitro-p-phenylenediamine (HC Blue //1, ring •4C, specific activity 113.6 /xCi/mg) in Loving Care Lotion //795, Darkest Brown, containing 1.48% of HC Blue//1. 2. DYEING PROCEDURE Process instructions, specific for each hair color product, were followed. Net weights of single application hair coloring products vary between 3 (semi-permanent dyes) and 4 fl. oz. (oxidative, permanent dyes). While this is sufficient to color up to 120g of hair, the average weight of female scalp hair 4 inches long is about 60g. The lotion/hair ratio commonly operative during hair coloring is thus 1.5-2.0 and the latter value was ,chosen to arrive at the quantity of the dye mixture that should be used in the studies with Rhesus monkey (the larger the lotion/hair ratio the greater is the availability of the dye for scalp penetration). A. Rhesus Monkeys Animals were anesthetized with 0.2 ml of ketamine and placed comfortably in a supine position on a laboratory bench top. The head of each monkey was rested on a specially designed sink support to facilitate the coloring process and assure quantitative collection of the rinse water. The dye lotion (total of 5g, in the case of oxidative dyes consisting of 2.5g of the dye solution and 2.5g of 6% aqueous hydrogen peroxide) was worked into the dry scalp hair until all the dye mixture was used (•3 min). The operator wore vinyl disposable gloves. Twenty minutes were allowed for the dyeing process to proceed (30 min in the case of the semi-permanent dye where a plastic turban was also used). After dyeing, the hair was rinsed with a microshower until the rinsing water was free of color. The excess water remaining on the hair was blotted with a paper towel and the dyed hair was shaven with electric clippers. B. Human Volunteers The coloring was performed with one subject at a time. The subject was seated in a chair having his head rested on a specially constructed sink support for comfort and easy collection of rinse water. The dye mixture (---110g for the oxidative color and T88g for the semi-permanent) was applied to dry hair and worked gently into the hair mass over a period of 5-8 min and left on the hair for an additional 20 (permanent color) or 30 (semi-permanent color) min. In the latter case, a plastic turban was wrapped around the hair for the dyeing period. The dyed hair was thoroughly rinsed, towel blotted, and shaven off with an electric clipper. 3. URINE COLLECTION A. Rhesus Monkeys After the dyeing procedure was completed, all of the monkeys were restrained in ophthalmological chairs, thus preventing their touching the scalp area. Urine samples