USE OF AUTORADIOGRAPHY TO STUDY LOCALIZATION OF GERMICIDES IN SKIN

SUMMARY.— An autoradiographic technique for studying skin deposition and localization is described and applied to a study of germicides in surfactants. The method involves the use of unfixed frozen sections exposed to dry emulsion‐coated slides. The radioactive germicides carboxy‐14C‐3,4,4′‐trichlorocarbanilide (TCC) in soap containing non‐soap detergent (NSD) and zinc or zirconium pyridine‐2‐thione‐1‐N‐oxide (PTO) in a shampoo were applied to the skin of guinea‐pigs. Auto‐radiograms of the skins showed that from soap, TGC was deposited on the stratum corneum, around the entrances to hair follicles, and was seen in the epidermis and dermis, but not in the follicles or sebaceous glands. From the NSD, TCC was seen in addition in the follicles and sebaceous glands. In one human subject, TCC from NSD was seen on the corneum, in the epidermis and dermis, hair follicles and sebaceous glands and also in the sweat glands. From the shampoo ZnPTO and ZrPTO were seen in guinea‐pig skin on the corneum and in the follicles but whereas ZrPTO was in the epidermis and dermis, ZnPTO was not. In all vehicles the largest proportion of germicide was deposited on the corneum. ZnPTO was shown to be soluble in sebum and to penetrate from sebum into only the hair follicles of guinea‐pigs. Scintillation counting of sections of guinea‐pig skin treated with TCC, ZnPTO and ZrPTO supported the autoradiographic evidence that most of the germicide remained on the corneum. Copyright © 1969, Wiley Blackwell. All rights reserved