DEPOSITION OF HEXACHLOROPHENE ON SKIN 533 water. Analysis o[ the alcohol extractions of the arms prodcued the following results: Concentration of Hexachlorophene on Arms Procedure Total (mg) 3,/cm '• Shower 1.34-1.66 2.2-2.7 Bath 1.48-1.56 2.4-2.5 These data show that approximately equivalent amounts of hexa- ½hlorophene are retained by the skin from both procedures. It is interesting to observe that the skin retained about 7.5% of the total hexachlorophene applied (20.0 mg in 1.0 g of 2.0% hexachlorophene soap). Bath Tests During these studies it was found that significant quantities of hexachlorophene would be retained by the skin after immersion in a bath containing low concentrations of the compound. Aliquots of a 10.0% hexachlorophene solution in 50% ethanol were added to a bath containing 5000 ml of warm water. The forearm was moistened in the bath, washed with a nonmedicated soap, then reimmersed in the bath for a period of five to ten minutes. Immediately after bathing the arms were immsered in alcohol the extract was condensed and analyzed for hexachlorophene. The results are listed in Table VII with each of the figures representing an individual test conducted on a single arm in a bath with the specified hexachlorophene content. The data clearly demonstrate that substantial quantities of hexachlorophene are depos- ited on the skin from baths containing relatively low concentrations of the compound. Bathing in water containing 4.0 mg/1 of hexachlorophene deposits approximately the same amount of compound on the skin Table V i i Bath Tests Hexachlorophene Concentration in Bath (mg/1) Hexachlorophene Concentration on Skin (-•/cm 2) 4.0 20.0 40.0 0.87, 0.87, 1.08, 1.26 1.35, 1.61, 1.77, 1.77,2.10 3.39, 4.19, 4.35, 5.00 5.65, 5.81 9.35, 9.35, 10.00

534 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table VIII Bath Oil Tests Product Hexachlorophene Concentration in Bath (rag/l) Hexachlorophene Concentration on Arm (T/cm 2) Bath Oil "A" (3.0% Hex.) Bath Oil "B" (4.0% Hex.) Bath Oil "C" (1.0% Hex.) Bath Oil "D" (3.0% Hex.) 6.0 4.2-8.2 12.0 10.6-17.4 3.0 2.7-4.2 10.0 5.2-6.8 as a single washing with a 2.0% hexachlorophene soap. Raising the hexachlorophene content of the bath results in an increased deposition on the skin. Several of these tests were repeated without washing with the nonmedicated soap, and analogous results were obtained. Bath Oils Skin retention tests were conducted in baths containing various bath oils [ormulated with hexachlorophene. Results of these tests, listed in Table VIII, demonstrate the relatively large quantities of hexachlorophene that can be put on the skin by use of these products. The wide spread in results for a given product can be attributed to non- uniform distribution of the floating oils through the bath. DISCUSSION AND SUMMARY Previous studies of hexachlorophene on the skin have employed bioassay (3), radioactive techniques (4), and ultraviolet analysis of alcohol extracts (5). Shemano and Nickerson (4) found that hexachloro- phene accumulated on the skin during the first three or four washes and remained relatively constant thereafter. Compeau (5) showed that hexachlorophene builtup during the first five to ten minutes of scrubbing but then accumulated no further after additional washing. He sug- gested that hexachlorophene was adsorbed on the skin through an ionic reaction with the cationic proteins of the skin. Recently, Parran (9) suggested the analogy between retention of antimicrobials on the skin and the problem of soil redeposition during the laundering of clothes. This study determined the hexachlorophene content of skin by a colorimetric analysis of concentrated alcohol extracts of the skin. It was found that the quantity of hexachlorophene applied to the skin was a major factor in controlling the amount retained. Increasing quantities were deposited by the following methods: