title: Absorption of topical tacrolimus (FK506) in vitro through human skin: comparison with cyclosporin A.
abstract: Cyclosporin A (CsA) is efficacious in many dermatoses as an oral but not as a topical form, while tacrolimus (FK506) has been shown to be effective in both forms. As inadequate skin absorption has been proposed as the reason for inefficacy of topical CsA, factors contributing to percutaneous absorption of FK506 and CsA were studied. Partitioning of FK506 and CsA between octanol and water, stratum corneum and water, and stratum corneum and isopropyl myristate was determined. Absorption of FK506 and CsA through dermatomed human cadaver skin was determined with in vitro flow-through cells. In partitioning experiments, CsA was more lipophilic than FK506. Both drugs were seen in comparable amounts in skin layers, but FK506 permeated the skin to a greater extent than CsA.
authors.affiliation: Department of Dermatology, University of California, School of Medicine, San Francisco, USA.
authors.forename: A I
authors.initials: AI
authors.lastname: Lauerma
authors.forename: C
authors.initials: C
authors.lastname: Surber
authors.forename: H I
authors.initials: HI
authors.lastname: Maibach
mesh_terms: D000287:Administration, Topical; D000328:Adult; D016572:Cyclosporine / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000493:pharmacokinetics*; D066298:In Vitro Techniques; D012869:Skin Absorption; D016559:Tacrolimus / Q000493:pharmacokinetics*
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine; D016559:Tacrolimus