Intracutaneous transport of orally administered fluconazole to the stratum corneum

Fluconazole administered at 150 mg/week for 1-5 weeks is effective orally against dermatophytes and yeast in stratum corneum. Clinical and mycological cure rates approach 90%, but the precise distribution of the drug within various layers of skin is uncertain. We administered fluconazole at 150 mg/week for 2 weeks to 5 volunteers. Distribution of fluconazole in biopsies of skin was imaged by energy dispersive analysis of X-rays (EDX) and transmission electron microscopy, and in cells by electron energy-loss spectroscopy (EELS). Eight hours after a second dose, EDX showed fluconazole highest and homogeneously distributed in stratum corneum, lower in the rest of the epidermis, and lowest in dermis. The highest fluconazole levels detected by EELS were in cytoplasmic inclusions of sweat and sebaceous glands and less in keratinocytes and dermal collagen. We conclude that fluconazole delivered to stratum corneum by direct diffusion from capillaries and in sweat is also in all likelihood transported in sebum.