The Use of Autoradiography to Study the Localization of Germicides in Skin

The study utilized autoradiography to examine the localization of germicides in skin, specifically focusing on carboxy-14C-3,4,4′-trichlorocarbanilide (TCC) and zinc or zirconium pyridine-2-thione-1-N-oxide (PTO) in guinea pigs and one human subject. TCC from soap was found on the stratum corneum, around hair follicle entrances, and in the epidermis and dermis, but not in follicles or sebaceous glands. In contrast, TCC from non-soap detergent (NSD) was also present in follicles and sebaceous glands. In the human subject, TCC from NSD was observed in the corneum, epidermis, dermis, hair follicles, sebaceous glands, and sweat glands. ZnPTO and ZrPTO from shampoo were located on the corneum and in follicles, with ZrPTO also in the epidermis and dermis, unlike ZnPTO. The largest germicide proportion was on the corneum, and ZnPTO was soluble in sebum, penetrating only hair follicles. Scintillation counting confirmed that most germicide remained on the corneum.